Developmental
Endocrinology Section, Laboratory of Toxicology, Environmental Toxicology
Program, Division of Intramural Research, National Institute of
Environmental Health Sciences, Research Triangle Park, North Carolina
27709 [R. R. N., E. P. B., W. N. J.], and Department of Pathology,
Wake Forest University School of Medicine, Wake Forest University,
Winston-Salem, North Carolina 27157 [B. B.]
Cancer
Causes & Control. 12(9):837-845, 2001 Nov. Hatch
EE. Herbst AL. Hoover RN. Noller KL. Adam
E. Kaufman RH. Palmer JR. Titus-Ernstoff L. Hyer
M. Hartge P. Robboy SJ.
Methods:
A cohort comprising 3899 DES-exposed and 1374 unexposed daughters
was followed for 13 years (1982-1995) for pathology-confirmed diagnoses
of high-grade squamous intraepithelial neoplasia (HSIL) of the genital
tract. Poisson regression analysis was used to compute relative
risks (RR) and 95% confidence intervals (95% CI), adjusting for
age, calendar year, and other covariates.
Results:
The RR (95% CI) among DES-exposed versus unexposed, based on 111
cases of high-grade disease, was 2.1 (1.2-3.8). Adjustment for screening
history estimated by the number of years since the last Pap smear
had little effect. Risk estimates were higher with earlier intrauterine
exposure; the RR (95% CI) for exposure within 7 weeks of the last
menstrual period was 2.8 (1.4-5.5). Only two cases of invasive squamous
cervical cancer occurred in total, precluding separate analysis.
Journal
of Pharmaceutical Sciences 64 (4) 535-598, 1975.
The
world population explosion has pointed out the need for new and
effective contraceptive agents...
...it
can be seen that 565 species of plants are known to have a folkloric
reputation for use as abortifacients, ecbolics, or emmenagogues.
Of this 565 species, 225 have been shown to elicit a stimulant response
when tested againsts uterine muscle either in vitro or in vivo.
Department
of Pediatrics, North Shore University Hospital, Manhasset and Department
of Pediatrics, Cornell University Medical College, New York.
We
have evaluated the hypothesis of a protective effect of human milk
on the development of insulin dependent diabetes mellitus (IDDM).
We studied the feeding histories of 95 diabetic children and compared
them with controls consisting of their non-diabetic siblings and
a pair matched group of non-diabetic peers of the same age, sex,
geographical location and social background. The incidence
of breast feeding in diabetic children was 18%. This was similar
to the control group. The duration of breast feedings was
also similar among all three groups. There was no difference
in the age of introduction of solid food between diabetic and non-diabetic
children. Twice as many diabetic children, however, received
soy containing formula in infancy as compared to control children.
The mean age of onset of IDDM was not related to the type of feeding
during infancy. The incidence of positive thyroid antibodies
was two and one half times higher in formula-fed diabetic children
that in breast-fed ones. In our studies we were unable
to document any relationship between the history of breast feeding
and subsequent development of IDDM in children.
1.
Breast-feeding
is strongly endorsed as the primary source of nutrition during the
first year of life for all infants.
2. In
families with a strong history of IDDM, particularly if a sibling
has diabetes, breast-feeding and avoidance of commercially available
cow’s milk and products containing intact cow’s milk protein during
the first year of life are strongly encouraged.
3. Since
the antigenicity of infant formulas and cow’s milk may be different
and there is no evidence against the use of formula for infants
whose mothers do not breast-feed, commercial infant formulas utilising
cow’s milk protein remain the approved alternate.
Wood-derived estrogens: studies
in vitro with breast cancer cell lines and in vivo in trout.
Toxicol Appl Pharmacol
1996 Feb;136(2):381-8
Mellanen P, Petanen T, Lehtimaki
J, Makela S, Bylund G, Holmbom B, Mannila E, Oikari A, Santti
R.
Institute
of Biomedicine, University of Turku, Finland.
The wood-derived compound, beta-sitosterol (purity > 90%),
was shown to be estrogenic in fish. It induced the expression
of the vitellogenin gene in the liver of juvenile and methyltestosterone-treated
rainbow trout. Structural similarities to beta-sitosterol notwithstanding,
cholesterol, citrostadienol, beta-sitostanol, and 5-androstene-3
beta,17 beta-diol, an estrogenic member of the androstenic steroid
group, were inactive. An abietic acid mixture (37% abietic acid,
6% dehydroabietic acid, and a remainder of unknown compounds)
showed slight hormonal activity in feed, but it was completely
inactive when given intraperitoneally in implants. The estrogenic
component of the abietic acid preparation was not identified.
In addition, to beta-sitosterol and abietic acid, several other
wood-derived compounds including betulin, isorhapontigenin, isorhapontin,
and pinosylvin were estrogenic in breast cancer cells (MCF-7 or
T-47D). However, betulin and pinosylvin, available in sufficient
amounts for in vivo testing, did not induce the expression of
the vitellogenin gene. Differences in the primary sequences of
human and fish estrogen receptors (hormone as well as DNA-binding
regions) or uptake and metabolism of the compounds may explain
the discrepancy between the two estrogen bioassays. Wood-derived
compounds such as beta-sitosterol, present in pulp and paper mill
effluents, may account for the weak estrogenicity of debarking
effluent seen at the vitellogenin expression bioassay.
Quotes
Fish exposed to
bleached pulp mill effluent (BKME) showed reduced plasma sex steroid
levels, decreased egg and gonad size, decreased occurrence of
secondary sexual characteristics, and an increased age to maturation.
Wood itself may
also be a source of contaminants responsible for endocrine abnormalities.
The presence of
high amounts of phytoestrogens in plants used for animal feed
and the deleterious effect of excessive exposure of animals to
phytoestrogens have been recognised for several decades.
The wood-derived
compounds studied, β-sitosterol and abeitic acid mixture,
were found to be estrogenic in juvenile and methyltestosterone-treated
fish.
In addition to
interaction with estrogen receptor, dietary estrogens or structurally
related compounds may compete with endogenous hormones for active
sites of metabolising enzymes, and thus reduce the concentrations
of biologically active endogenous hormones.
Pulping processes
Interscience Publishing,
1965, pp 226-227 & 826-827.
Rydholm, SA
Quotes
The unsaponifiable
neutral substances of the wood extractives contain higher fatty
alcohols such as lignoceryl alcohol, as well as plant hormones,
the phytosterols, mainly β-sitosterol, CXXXIV, and β-sitostanol,
CXXXV, in the approximate proportions of 30:63:7.
Their utilization
in the production of sex hormones has been investigated on a fairly
large scale, but was not found to be competitive with the alternative
source, cholosterol from wool fat.
It further contains
phytosterols, mainly β-sitosterol and β-sitostanol,
which have been subject to interest for commercial production
of sex hormones otherwise made from cholosterol.
Hormonally Active Agents in the
Environment
National Research
Council of the American Academyof Sciences,
National
AcademyPress 1999, pp 78 & 85.
Quotes
Potential exposure
to plant estrogens found in wood has been assessed by various
in vitro and in vivo bioassays. Wood-derived estrogens,
such as beta-sitosterol, could represent environmental hormone
exposures, particularly from pulp and paper mill effluents, downstream
of wood-processing facilities. Mellanen et al. (1996) used
two breast-cancer cell lines in vitro (MCF7 and T-47D) and expression
of the vitellogenin gene in rainbow-trout livers to estimate estrogenic
activity of wood-derived compounds. Some compounds, such
as beta-sitosterol, were estrogenic in human and fish bioassays,
but some phytoestrogens, such as betulin and pinosylvin, were
estrogenic only in humans.
Estrogen-specific 17 beta-hydroxysteroid oxidoreductase type 1
(E.C. 1.1.1.62) as a possible target for the action of phytoestrogens.
Proc Soc Exp Biol
Med 1995 Jan;208(1):51-9
Makela S, Poutanen M, Lehtimaki
J, Kostian ML, Santti R, Vihko R.
Institute of Biomedicine, University
of Turku, Finland.
Several plant estrogens, especially coumestrol and genistein,
were found to reduce the conversion of [3H]estrone to [3H] 17
beta-estradiol catalyzed by estrogen-specific 17 beta-hydroxysteroid
oxidoreductase Type 1 (E.C. 1.1.1.62) in vitro. Coumestrol, the
most potent inhibitor in our experiments, is the best inhibitor
of the enzyme known to date. All compounds with inhibitory effects
were also estrogenic. However, structural demands for 17 beta-HSOR
Type 1 inhibition and estrogenicity of tested compounds in breast
cancer cells (judged by increased cell proliferation) were not
identical. Zearalenone and diethylstilbestrol, both potent estrogens,
did not inhibit 17 beta-HSOR Type 1. Thus, changes in the estrogen
molecule may discriminate between active sites of 17 beta-HSOR
Type 1 and estrogen binding sites of the ER. The effects of these
compounds in vivo cannot be predicted on the basis of these results.
Inhibition of 17 beta-HSOR Type 1 enzyme could lead to a decrease
in the availability of the highly active endogenous estrogen.
However, these compounds are estrogenic per se, and they may thus
replace endogenous estrogens. Additional studies are needed
to further understand the role of these plant estrogens in the
etiology of hormone-dependent cancers. It is not easily conceivable
how the chemopreventive action of Asian diets, possibly mediated
by phytoestrogens in soya products, can be based on the inhibition
of estrone reduction at the target cells by phytoestrogens or
related compounds, unless they are "incomplete estrogens"
(i.e., unable to induce all effects typical of endogenous estrogens).
Quotes
Compounds with
high binding affinities for ER (a specific intracellular endocrine
receptor) are generally the most active biologically and enhance
proliferation of estrogen-responsive tumor cells.
None of the
phytoestrogens we studied earlier (coumestrol, genistein, biochanin
A, and zearalenone reduced the proliferation rate of 17β-estradiol-stimulated
breast cancer cells...
In addition
to their interaction with ER (a specific intracellular endocrine
receptor), dietary estrogens or structurally related compounds
might compete with endogenous estrogens for the active site of
the estrogen biosynthesizing and metabolizing enzymes and thus
reduce the concentration of biologically active endogenous estrogens.
Tumor Sterols
Metabolism 969;
18 (8): 646-651.
Day EA, Gray T, Beeler M, Beeler
MF.
Tumor tissue, including
breast cancer, thyroid carcinoma, uterine carcinoma and granulosal
thecal cell ovarian tumor, from twelve different patients, was
analysed for sterol content by thin-layer and gas-liquid chromatography.
Cholesterol was present in large amounts in all. A sterol
with the retention time of desmosterol was present in 11; one
with the retention time of stigmasterol in 3; of which, 2 also
contained a sterol with the retention time of campesterol, and
1 of B-sitosterol. Thus, the finding of osteolytic sterols
in breast cancer by Gordan and associates is partially confirmed
and extended.
Quotes
The present
study tends to confirm, in part, reports by Gordan and associates
of the presence of osteolytic phytosterols in breast cancers,
postulated by them to account for the frequent serious degree
of hypercalcemia seen in these patients. We have demonstrated
evidence for their presence in one of eight breast cancers as
well as in a follicular carcinoma of the thyroid metastatic to
the lung, and in a malignant mixed Mullerian tumor of the uterus.
We found no
evidence of the presence of these sterols in normal tissue.
Identification
of osteolytic sterols in human breast cancer
Transactions of
the Association of American Physicians 1967; 53: 183-189
Gordan GS, Fitzpatrick
ME, Lubich WP.
Quotes
Hypercalcemia
is a serious, life-threatening emergency. The most common
cause of hypercalcemia is malignancy, and the one tumor accounting
for two-thirds of all cases of the hypercalcemia of malignancy
is breast cancer. In most cases, the hypercalcemia of breast
cancer is associated with osteolytic metastases. As with
other malignancies, however, hypercalcemia occasionally occurs
in the absence of osseous lesions.
Hypercalcemia
is a frequent cause of death and disability in breast cancer,
occasionally even in the absence of osseous metastases
It is not caused
by parathyroid hormone or vitamin D
A series of
plant sterols has been identified in breast cancer extracts and
in the plasma of patients with breast cancer. Some of these,
campesterol, stigmasterol and sitosterol, are also found in normal
plasma. Breast cancer is characterised by an abnormality
of sterol metabolism leading to the accumulation of sterol esters,
especially the osteolytic, short chained fatty acid acid esters
of stigmasterol and 7-dehydrositosterol. Either or both
was found in the plasma of all 25 cases - 19 disseminated and
6 local. They were not found in normal non-lactating women.
It is suggested
that the esters of stigmasterol and of 7-dehydrositosterol may
play a role in the hypercalcemia of breast cancer.
Significance of dietary plant sterols in man and experimental
animals
Mayo Clin. Proc.
1971; 46: 549-559
M. T Ravi Subbiah.
Quotes
Plant sterols
and their esters have been isolated from plasma and breast extracts
of a number of patients with breast cancer in concentrations much
higher than is found in normal persons. This has been confirmed
in patients with thyroid or renal carcinoma. Indeed, the
esters of certain plant sterols have been shown to possess high
osteolytic activity.
Taber's
Cyclopedic Medical Dictionary
18th edition, 1999
pp 1367
Hypercalcemia
An excessive amount of calcium in the blood.
The causes of this condition include primary hyperthyroidism,
lithium therapy, malignancies including solid tumors and hematological
malignancies, vitamin D intoxication, hyperthyroidism, vitamin
A intoxication, aluminium intoxication; and milk-alkali syndrome.
The
Merck Manual of Diagnosis and Therapy
17th edition, 1999
pp 145-151
M. H Beers, R.
Berkow, Editors
Hypercalcemia Quotes
Hypercalcemia usually results from excessive bone
resorption of which the principle causes are;
- Parathyroid hormone excess
|
- Humoral hypercalcemia of malignancy
|
- Malignancy with bone metastases
|
| |
| |
| |
| |
The clinical
manifestations of hypercalcemia include constipation, anorexia,
nausea and vomiting, abdominal pain and ileus.
Elevation
of plasma Ca is associated with emotional lability, confusion,
delirium, psychosis, stupor and coma. Neuromuscular involvement
may cause prominent skeletal muscle weakness.
Phytosterols
in Aortic Tissue in Adults and Infants.
J.
Lab. Clin. Med. 88 (6) December 1976: pp914-921
M.
J. Mellies, T. T. Ishikawa, C. J. Glueck, K. Bove, J. Morrison
Quotes
Plant sterols
are structurally similar to cholesterol, all having a cyclopentenophenanthrene
ring with 3-beta hydroxy substitution and a 5-6 double bond.
Beta-sitosterol is proportionately the predominant plant sterol
in dible oils and grains, with smaller amounts of campesterol
and stigmasterol. In adult diets, plant sterols are estimated
to account for about one tenth of 1 per cent of total calories
and 20 per cent of total sterols. Studies in adults using
labelled beta-sitosterol suggest that less than 5 per cent of
orally administered sitosterols are absorbed, representing about
one thenth of the amount of cholesterol absorbed under similare
conditions.
There is
however an apparent increase in absorption of dietary phytosterols
in infancy and childhood. In infants and children fed diets
rich in phytosterols, plasma phytosterols rose from less than
2 to 9 mg. per 100 mL. The implications of long-term three-
to fivefold elevations of the plasma phytosterols in infancy and
childhood are unknown.
In adults
with mature atheromatous lesions, plant sterols are present in
appreciable amounts. The implications of these findings
are unknown and their relationship to deposition of cholesterol
in atheromatous and in normal aortic tissues remains to be elucidated.
Although
balance studies of phytosterol absorption have not been done in
human infants, it appears that phytosterol-rich diets induce elevations
of plasma phytosterol five- to 15-fold above that observed in
adults. Once abserbed, phytosterols are catabolised, esterified,
and handled in a fashion similar to, but not exactly the same
as cholesterol. ...there is no endogenous synthesis
of beta-stiosterol.
...the correlation
between cholesterol and phytosterols (excluding campesterol) suggests
parallel accumulation of these sterols.
...it is
speculated that phytosteols may accumulate in infants faster than
cholesterol.
In contrast,
the ratio of plasma cholesterol to plant sterol in vegetable-oil
formula-fed infants was considerably lower than relative tissue
ratios. The early increments of aortic tissue phytosterol
in infants on phytosterol-rich diets might be speculatively related
to relatively low cholesterol and relatively high plasma phytosterol.
In the mature
adult atheromatous lesion, where large amounts of cholesterol
were present, there were notable increases in plant sterols.
Adverse
effects of phytoestrogens-7. Effect of beta-sitosterol treatment
on follicular development, ovarian structure and uterus in the
immature female sheep.
Cell Mol
Biol 1980;26(3):255-66
El
Samannoudy FA, Shareha AM, Ghannudi SA, Gillaly GA, El Mougy SA.
Abstract
The daily
subcutaneous injection of β-sitosterol for 20 days in the
immature female sheep resulted in a preliminary increase in the
ovarian and uterine weights, which was then followed at a dose
of 20 mg by a marked reduction in their weights. In the
ovary, with increase in the dose of β-sitosterol, follicular
growth was inhibited and large Graaffian follicle exhibited sigh=ns
of atresia or induced ovulation. Petechial haemorrhages
were evident in the ovarian structure and on the outer layer of
the uterine endothelium. Disturbances in the alkaline phosphatase
distribution were seen in the zona pellucida and interstitial
gland of the ovary. In the uterus, the alkaline phosphatase
distribution increased in the uterine glands and endothelium at
doses of 0.5 and 1 mg. At a dose of 20 mg there was a sudden
significant decrease in the uterine alkaline phosphatase distribution.
The activity of the acid phosphatase decreased continuously with
dose and time of β-sitosterol injection. Moreover,
there was a slight modification in the reactivity of the oxidative
enzymes (SD.NADH2-TR and NADPH2-TR) as well as the cholinesterases
after β-sitosterol injection.
Quotes
From the
developing egg to the delivery of a foetus, the female reproductive
cycle is a complex and delicately balanced interplay of events,
any one of which, if distorted, may interrupt the succeeding processes.
Therefore the addition of steroids to the body imposes alterations
on the reproductive system.
...observations
that increasing the dose of oestradiol beyond the optimal levels
result in a decreased uterine growth response and that continued
treatment with high doses of oestrogen first leads to a disproportionate
overgrowth of the myometrium and eventually to a refractory state
during which both endometrium and myometrium undergo atrophy.
This was an obvious observation in our case with the use of β-sitosterol.
The similarity
between β-sitosterol and oestrogen on the uterus does not
hold with the effect of β-sitosterol on the ovary.
The present result of the general significant decrease of sheep
ovarian weight under the influence of β-sitosterol is a repetition
for a previous picture on the effect of β-sitosterol on the
rabbit ovarian weight...
Yet in our
experiment, β-sitosterol inactivated the process of follicular
development.
The antifertility
effectiveness of phytoestrogens has been thought to reside in
their ability to suppress ovulation by interference with the normal
interactions of the hypothalamus and pituitary, which results
in alterations in the secretion of gonadotrophins. These
findings have been substantiated. Thus the β-sitosterol
action, as demonstrated by failure of growth of the follicles,
increased percentage of atresia and the formulation of cyctic
ovaries (which could resemble the multiple cycsts of Stein-Loeventhal
ovary in humans) could be explained on the basis that β-sitosterol
could have blocked the synthesis or/and production of gonadotrophins
from the pituitary or their releasing factors from the hypothalamus.
Therefore,
β-sitosterol will disturb the cell permeability and the absorption
of nutrient material by the uterine cells, through the disturbance
occurring on the alkaline phosphatase which is responsible for
such an action.
In addition, the influence of β-sitosterol
on the milieu medic of the uterus presumably affects the transmission
of nerve impulses in the uterus.
Masculinization
of female mosquitofish by exposure to plant sterols and Mycobacterium
smegmatis.
Bull Environ
Contam Toxicol 1985 Nov;35(5):627-32
Denton
TE, Howell WM, Allison JJ, McCollum J, Marks B
A study by
Howell et al. (1980) revealed a population of the sexually dimorphic
poeciliid mosquitofish, Gambusia affininis Holbrooki,
in a stream receiving papermill effluents. In this population,
the females were strongly masculinised showing both physical secondary
sex characteristics and reproductive behaviour of males.
It is well
documented that plant sterols are widespread within the plant
kingdom, especially among pine trees used in the pulping industry,
and that sitosterols are the most abundant of these sterols.
At one time,
the bioconversion of soybean sterols to β-sitosterol, campesterol,
and stigmasterol was considered an alternative source of intermediates
for steroid manufacture.
Howell et
al. (1980) found masculinised Gambusia affininis Holbrooki
as far downstream as 4 miles from the location where pulp
chemicals were being discharged. Masculinised forms were
not found above the point where papermill effluents were entering
the stream.
It is well
known that the quantity of plant sterols are greatly elevated
in papermill effluents. The majority of the sitosterols
are found in the resin fractions of conifers.
All Gambusia
exposed to plant sterols and Mycobacterium developed male-like
gonopodia.
These characteristics
did not regress when transformed fish were removed to their natural
environment which was free of plant sterol products.
It is our
considered opinion that both B-sitosterol and stigmastanol are
capable of being degraded by Mycobacterium into substances capable
of modifying anal fin rays of Gambusia. Both of these substances
are present in different amounts in the two soybean extracts used
in this study.
It is probable
that all three compunds are degraded into androstane-like compounds.
The removal
of sitosterols during the pulping process presents great difficulty
as they are only slightly hydrophyllic at all pH levels.
Papermill effluents released into settling ponds can possibly
contain enough sitsterols and micro-organisms to produce androgens
which are released into streams.
Gonopodial
Morphogenesis in Female Mosquitofish, Gambusia affinis affinis,
Masculinized By Exposure to Degradation Products From Plant Sterols..
Environmental
Biology of Fishes 1989 24(1):43-51
Howell
WM, Denton TE
Female mosquitofish,
Gambusia affinis affinis, were masculinised by exposure
to degradation products (presumably steroids) of the plant sterol,
stigmasterol.
In 1980,
a puzzling situation was presented regarding a population of Gambia
affinis holbrooki inhabiting a stream polluted by pulp wastes
from a paper-mill (Howell et al. 1980). All females within
this population were abnormal in that they possessed a well-developed,
male-like gonopodium and displayed typical male reproductive behaviour.
For example
tall oil, an abundant substance in papermill effluent, contains
3% plant sterols, consisting of 17 different compounds, of which
sitosterol and campesterol comprise 85%. Laboratory experiments
have duplicated the same masculinising effects that occur in female
Gambusia living in streams receiving wastes from pulping
of pinewood chips.
We know of
no hormone treatment system that will product the 3-4-5 termination
complex in female Gambusia as rapidly as exposure to biodegraded
stigmastanol. The degraded stigmastanol apparently acts
as a stimulus to turn on specific inactive gene complexes which
otherwise would never be active during the life of a female
Gambusia. This would never occur in a normal female
Gambusia. Animal behaviourists could use this model
to investigate changes in behaviour and social interactions in
masculinised female Gambusia.
Effect
of beta-sitosterol on uterine biochemistry: a comparative study
with estradiol and progesterone.
Biochem Mol
Biol Int 1993 Nov;31(4):659-68
Malini
T, Vanithakumari G.
Department
of Endocrinology, Dr. ALM Post Graduate Institute of Basic Medical
Sciences, Taramani, Madras, India.
Administration of estradiol/progesterone to ovariectomized animals
significantly increased the uterine weight, RNA, DNA and protein
concentrations. Similarly, administration of beta-sitosterol alone
or in combination with estradiol caused a marked increase in the
above parameters and the maximum influence was evident only after
median and high dose treatments. However, administration of median/high
dose of beta-sitosterol along with progesterone accentuated only
the RNA and protein concentrations but exerted an inhibitory effect
on sitosterol-induced increment in uterine weight and DNA concentrations.
It is well-established
that mammalian uterus is both an estrogen and progesterone responsive
organ. Endogenous steroids as well as synthetis estrogens,
progestins and androgens are effective in stimulating the growth
of uterus. ...it is also well known that depending on dose
and time of administration, one steroid may augment or antagonise
the activity of another sex steroid.
In the present
study also, estradiol administration induced a significant increase
in the uterine weight, associated with hyperemia and hyperplasia
of the uterine tissue. B-sitosterol provoked a similar increase
in uterine wet weight, suggesting the possible estrogenicity of
the compound. The observation confirms and extends the reports
from earlier workers. Further the uterine growth response
to B-sitosterol was found to be dose-dependent and only a high
dose produced a greater increase in uterine weight with massive
oedema comparable to that of estradiol stimulation.
THe observed
increase in tissue wet weights of rats treated with B-sitosterol
either individual or concurrently with estradiol may primarily
be attributed to the hypertrophy and hyperplasia of uterine tissue
as evidenced histologically
Goitrogenic
and estrogenic activity of soy isoflavones.
Environ
Health Perspect 2002 Jun;110 Suppl 3:349-53 Doerge
DR, Sheehan DM.
Division
of Biochemical Toxicology, National Center for Toxicological Research,
Jefferson, Arkansas, USA. Soy
is known to produce estrogenic isoflavones. Here, we briefly review
the evidence for binding of isoflavones to the estrogen receptor,
in vivo estrogenicity and developmental toxicity, and estrogen
developmental carcinogenesis in rats. Genistein, the major
soy isoflavone, also has a frank estrogenic effect in women.
We then focus on evidence from animal and human studies suggesting
a link between soy consumption and goiter, an activity independent
of estrogenicity. Iodine deficiency greatly increases soy antithyroid
effects, whereas iodine supplementation is protective. Thus, soy
effects on the thyroid involve the critical relationship between
iodine status and thyroid function. In rats consuming genistein-fortified
diets, genistein was measured in the thyroid at levels that produced
dose-dependent and significant inactivation of rat and human thyroid
peroxidase (TPO) in vitro. Furthermore, rat TPO activity was dose-dependently
reduced by up to 80%. Although these effects are clear and reproducible,
other measures of thyroid function in vivo (serum levels of triiodothyronine,
thyroxine, and thyroid-stimulating hormone; thyroid weight; and
thyroid histopathology) were all normal. Additional factors appear
necessary for soy to cause overt thyroid toxicity. These clearly
include iodine deficiency but may also include additional soy
components, other defects of hormone synthesis, or additional
goitrogenic dietary factors. Although safety testing of natural
products, including soy products, is not required, the possibility
that widely consumed soy products may cause harm in the human
population via either or both estrogenic and goitrogenic activities
is of concern. Rigorous, high-quality experimental and human research
into soy toxicity is the best way to address these concerns.
Similar studies in wildlife populations are also appropriate.
The effect of neonatal exposure
to diethylstilbestrol, coumestrol, and beta-sitosterol on pituitary
responsiveness and sexually dimorphic nucleus volume in the castrated
adult rat.
Proc Soc Exp
Biol Med 1995 Jan;208(1):72-7
Register B, Bethel MA, Thompson N, Walmer D, Blohm P, Ayyash L,
Hughes C Jr.
Department of Obstetrics and Gynecology, Duke University Medical
Center, Durham, North Carolina 27710.
The neonatal hormone environment influences the sexually differentiated
patterns of development. Estrogens, derived from intracerebral
aromatization, promote male pattern development of the central
nervous system. The purpose of this study was to determine the
effects of neonatal exposure to environmental estrogens on luteinizing
hormone (LH) secretion and development of the sexually dimorphic
nucleus of the medial preoptic area (SDN-POA) in castrated adult
rats. Neonatal rats of both sexes received injections of either
corn oil, 0.1 microgram diethylstilbestrol (DES), 3 micrograms
beta-sitosterol (B1), 30 micrograms beta-sitosterol (B2), 0.1
microgram coumestrol (C1), 1 microgram coumestrol (C2), or 10
micrograms coumestrol (C3) on Day 1-10 of life and were castrated
on Day 21. Right heart catheters were placed on Day 42, and GnRH
(50 ng/kg) was administered. Blood was sampled for LH at 0-, 5-,
10-, 15-, and 30-min intervals. All doses of beta-sitosterol and
coumestrol elicited increased basal levels of LH in females. In
males, B1, B2, C2, and C3 increased basal levels of LH. The GnRH-induced
LH increase was prevented in females treated with diethylstilbestrol
and 10 micrograms of coumestrol. Males in all treatment groups
exhibited GnRH-induced LH surges. The animals were sacrificed
by decapitation on Day 49. Volumes of the SDN-POA of the groups
were compared. Treatment with the agents did not result in significantly
increased SDN volume in females; nor was there a difference in
SDN size among the male groups. These data show that exposure
to environmental estrogens early in development alters both postpubertal
pituitary response to GnRH and basal LH secretion in females
and alters only basal LH secretion in males. No significant enlargement
(i.e., masculinization) of the SDN-POA was exhibited.
Safety Issues of Soy Phytoestrogens in
Breast Cancer Patients
J
Clin Oncol, Volume 20(13).July 1, 2002.3040-3041
de
Lemos, M.
To the Editor:
The results of Van Patten et al confirmed previous findings
that soy phytoestrogens have minimal efficacy for menopausal symptoms
in breast cancer patients. However, I am concerned that patients
in neither study were apparently informed of the potential stimulatory
effects of phytoestrogens on breast tumor. Similar omission
would have raised ethical concerns if pharmaceutical drugs were
involved.
At concentrations below 10 µmol/L, phytoestrogens can stimulate
breast tumor growth and antagonize the antitumor effects
of tamoxifen, particularly in an environment of low endogenous
estrogen. In contrast, phytoestrogens inhibit breast tumor
growth and enhance the antitumor effects of tamoxifen at concentrations
above 10 µmol/L. In humans, serum phytoestrogen concentrations
attained after acute or chronic intake of phytoestrogens were
much lower than 10 µmol/L.
Without long-term human data, cancer risk assessments need to
be cautious and assume that substances that promote tumor growth
in preclinical studies may pose similar risks clinically.
Hence, to weigh the potential risks versus benefits before using
phytoestrogens for unproven indications, breast cancer patients
should be informed that phytoestrogens have the potential to stimulate
tumor growth.
Mário de Lemos
Effects of the dietary phytoestrogens
daidzein and genistein on the incidence of vulvar carcinomas in
129/J mice.
Cancer
Detect Prev 2001;25(6):527-32
Thigpen
JE, Locklear J, Haseman JK, Saunders H, Grant MF, Forsythe DB.
Comparative
Medicine Branch, National Institute of Environmental Health Sciences,
Research Triangle Park, North Carolina 27709, USA.
The objective of
this study was to determine the effect of dietary phytoestrogens
on the incidence of spontaneous vulvar carcinomas in 129/J mice
using three natural ingredient diets and two purified diets containing
predetermined levels of daidzein and genistein. Eighty weanling
female mice without clinical evidence of vulvar carcinomas were
randomly assigned 16 per diet to each of 5 test diets. Mice were
clinically examined for vulvar masses weekly for 3 months and
at monthly intervals thereafter. Vulvar carcinomas in representative
groups of mice were confirmed using routine histological procedures.
The incidence of vulvar carcinomas increased sharply in mice on
all test diets during the first 2 months with minor changes during
the remainder of the study. Within one month, the incidence
of vulvar carcinomas in mice fed the AIN-76A modified soy protein
diet was significantly (P < .05) increased over those of mice
fed the AIN-76A modified casein diet, the #5K96, or the # 5058
diet. At three months, the incidence of vulvar carcinomas
in mice fed the soy protein diet was significantly (P < .05)
increased over those of mice fed the NIH-31 diet or the PMI #5K96
diet. There was a marginally significant (P < .10) correlation
between the total daidzein and genistein levels in the five test
diets and the incidence of vulvar carcinomas in mice as determined
by clinical examination. We concluded that dietary levels of
daidzein and genistein were associated with an increase in the
incidence of vulvar carcinomas in mice and that the 129/J
mouse may provide an animal model for studying the development
of vulvar carcinomas.
Effects of soy phytoestrogens genistein
and daidzein on breast cancer growth.
Ann
Pharmacother 2001 Sep;35(9):1118-21.
de
Lemos ML
Provincial
Systemic Therapy Program, British Columbia Cancer Agency, Vancouver,
Canada
OBJECTIVE: To determine
whether genistein and daidzein, the major phytoestrogens in soy,
can stimulate breast cancer growth. DATA SYNTHESIS: Systematic
search through primary English-language literature on MEDLINE
(1966-January 2001), EMBASE (1982-January 2001) and Current Contents
(1998-January 2001). DATA SOURCES: Genistein and daidzein at low
concentrations were found to stimulate breast tumor growth in
in vitro and in vivo animal studies, and antagonize the antitumor
effect of tamoxifen in vitro. At high concentrations, genistein
inhibited tumor growth and enhanced the effect of tamoxifen in
vitro. CONCLUSIONS: Genistein and daidzein may stimulate existing
breast tumor growth and antagonize the effects of tamoxifen. Women
with current or past breast cancer should be aware of the risks
of potential tumor growth when taking soy products.
Infant feeding with soy formula milk:
effects on the testis and on blood testosterone levels in marmoset
monkeys during the period of neonatal testicular activity.
Hum
Reprod 2002 Jul;17(7):1692-703
Sharpe
RM, Martin B, Morris K, Greig I, McKinnell C, McNeilly AS, Walker
M.
MRC Human
Reproductive Sciences Unit, Centre for Reproductive Biology, 37
Chalmers Street, Edinburgh EH3 9ET, UK.
BACKGROUND: This
study has addressed concerns about possible effects of feeding
human infants soy formula milk (SFM). METHODS: This is a feeding
study in marmosets, using a mainly co-twin design. From 4-5 until
35-45 days of age, co-twin males were fed by hand with either
standard (cow) formula milk (SMA = controls) or with SFM for approximately
8 h each day (2 h at weekends) and intake related to bodyweight.
Blood samples were collected at 18-20 and at 35-45 days of age
in 13 sets of co-twins plus two non-twin males per group and,
at the later age, seven sets of co-twins were killed and the testes
and pituitary gland fixed for cell counts. RESULTS: Weight gain
and formula intake were similar in both feeding groups. SMA-fed
males had mean testosterone levels of 2.8-3.1 ng/ml, typical of
the 'neonatal testosterone rise', whereas SFM-fed males
exhibited consistently lower mean levels (1.2-2.6 ng/ml); paired
comparison in SMA-and SFM-fed co-twins at day 35-45 revealed 53-70%
lower levels in 11 of 13 co-twins fed with SFM (P = 0.004).
Further evidence for suppression of testosterone levels in
SFM-fed males came from comparison of the frequency of low testosterone
levels (<0.5 ng/ml). In historical controls aged 35-45 days,
two out of 22 values were <0.5 ng/ml, a similar frequency as
found in control SMA-fed males (one out of 15 values <0.5 ng/ml).
In contrast, 12 out of 15 values for SFM-fed males were
<0.5 ng/ml (P < 0.001). There was no consistent relationship
between SFM intake/g and testosterone levels. Paradoxically, the
mean number of Leydig cells per testis was increased by 74% (P
< 0.001) in co-twins fed SFM, when compared with their SMA-fed
brothers, whereas no significant changes were found in numbers
of Sertoli and germ cells. Because of the lack of gonadotrophin
assays, the number of immunopositive LHbeta and FSHbeta cells
in the pituitary gland, and their ratio, were determined but no
consistent difference was found between SMA- and SFM-fed twins.
CONCLUSIONS: Based on the average isoflavone content of the
SFM brand used, intake of isoflavones was estimated at 1.6-3.5
mg/kg/day in the SFM-fed marmosets which is 40-87% of that reported
in 4 month human infants fed on a 100% SFM diet. It is therefore
considered likely that similar, or larger, effects to those shown
here in marmosets may occur in human male infants fed with SFM.
Whether the changes described result in longer-term effects is
under investigation.
The effect of phytoestrogens
on the female genital tract.
J
Clin Pathol 2002 Jun;55(6):401-7
Burton
JL, Wells M.
Section of
Oncology and Pathology, Division of Genomic Medicine, University
of Sheffield Medical School, Beech Hill Road, S10 2RX, UK. j.l.burton@shef.ac.uk
Environmental
oestrogens have been implicated in the pathogenesis of hormonally
treated cancers (such as breast and prostate cancer), male infertility,
and abnormalities of the male and female reproductive tracts.
They may be derived from plants (phytoestrogens), pharmaceuticals,
or other synthetic compounds not originally intended to have oestrogenic
activity (including soy based infant formulas). This review
will discuss the evidence from both animal studies and humans
for an effect of these ubiquitous compounds on the development
of the human female genital tract, in addition to prolonging the
menstrual cycle, alleviating symptoms of the menopause, and protecting
against the development of endometrial carcinoma.
Some Take Home Messages
Environmental oestrogens have been implicated in the pathogenesis
of hormonally treated cancers (such as breast and prostate cancer),
male infertility, and abnormalities of the male and female reproductive
tracts.
Environmental oestrogens may be derived from plants (phytoestrogens),
pharmaceuticals, or other synthetic compounds not originally intended
to have oestrogenic activity.
Exposure to these compounds results in structural and functional
abnormalities in the female genital tract of fish, rodents, and
livestock.
The
age at first exposure and the duration of exposure are important,
neonatal exposure having the potential to produce lasting morphological
abnormalities and a persistent (gonad independent) oestrous state.
The
human diet is rich in phytoestrogens, and such compounds are also
present in soy based infant formulas, which may be a cause for
concern.
To
date, there is little evidence that such compounds affect human
female genital tract development or fertility, probably because
of the ubiquitous nature of such compounds in the environment
and a lack of investigation, rather than the absence of a correlation.
Dietary genistein negates the inhibitory
effect of tamoxifen on growth of estrogen-dependent human breast
cancer (MCF-7) cells implanted in athymic mice.
Cancer
Res 2002 May 1;62(9):2474-7
Ju
YH, Doerge DR, Allred KF, Allred CD, Helferich WG.
Department
of Food Science and Human Nutrition, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61801, USA.
The use of dietary
isoflavone supplements by postmenopausal women with breast cancer
is increasing. We investigated interactions between the soy
isoflavone, genistein, and an antiestrogen, tamoxifen (TAM), on
the growth of estrogen (E)-dependent breast cancer (MCF-7) cells
implanted in ovariectomized athymic mice. We hypothesized that
weakly estrogenic genistein negate/overwhelm the inhibitory effect
of TAM on the growth of E-dependent breast tumors. Six treatment
groups were used: control (C); 0.25 mg estradiol (E2) implant
(E); E2 implant + 2.5 mg TAM implant (2.5 TE); E2 implant + 2.5
mg TAM implant + 1000 ppm genistein (2.5 TEG); E2 implant + 5
mg TAM implant (5 TE), and E2 implant +5 mg TAM implant +1000
ppm genistein (5 TEG). Treatment with TAM (2.5 TE and 5 TE) suppressed
E2-stimulated MCF-7 tumor growth in ovariectomized athymic mice.
Dietary genistein negated/overwhelmed the inhibitory effect
of TAM on MCF-7 tumor growth, lowered E2 level in plasma, and
increased expression of E-responsive genes (e.g., pS2, PR, and
cyclin D1). Therefore, caution is warranted for postmenopausal
women consuming dietary genistein while on TAM therapy for E-responsive
breast cancer.
Physiological concentrations of dietary
genistein dose-dependently stimulate growth of estrogen-dependent
human breast cancer (MCF-7) tumors implanted in athymic nude mice.
J
Nutr 2001 Nov;131(11):2957-62
Ju
YH, Allred CD, Allred KF, Karko KL, Doerge DR, Helferich WG.
Department
of Food Science and Human Nutrition, University of Illinois at
Urbana-Champaign, Urbana, IL 61801, USA.
Previously our
laboratory has shown that the soy isoflavone, genistein, stimulates
growth of human breast cancer (MCF-7) cells in vivo and in vitro.
In this study, the dose-response analysis of genistein at the
physiologically achievable concentration range between 125 and
1,000 microg/g in the diet was conducted in ovariectomized athymic
nude mice implanted with MCF-7 cells. We hypothesized that genistein
at this concentration range can stimulate dose-dependently the
breast tumor growth, cell proliferation and an estrogen-responsive
pS2 gene induction. Tumor size and body weight were monitored
weekly. At completion of the study, we analyzed cellular proliferation
of tumors using incorporation of BrdU, pS2 expression of tumors
using a Northern blot analysis and total genistein level in plasma
using liquid chromatography-isotope dilution mass spectrometry
(LC-ES/MS). Dietary genistein (> or = 250 microg/g) increased
tumor size in a dose-dependent manner [8.4x the negative control
(NC) group in the 250 microg/g group, 12.0x in the 500 microg/g
group, 20.2x in the 1,000 microg/g group and 23.2x in the positive
control (PC) group]. The percentage of proliferating cells
was significantly increased by genistein at and above 250 microg/g
(5.3x the NC group in the 250 microg/g, 5.6x in the 500 microg/g,
5.0x in the 1,000 microg/g and 4.8x in the PC group). Expression
of pS2 mRNA was also significantly increased with increasing dietary
genistein levels (11.25x the NC group in the 500 microg/g group
and 15.84x in the 1,000 microg/g group). Total plasma genistein
concentrations were between 0.39 and 3.36 micromol/L in mice fed
between 125 and 1,000 microg/g genistein. In conclusion, dietary
treatment with genistein at physiological concentrations produces
blood levels of genistein sufficient to stimulate estrogenic effects,
such as breast tumor growth, cellular proliferation and pS2 expression
in athymic mice in a dose-responsive manner similar to that seen
in vitro.
Dietary genistin stimulates growth
of estrogen-dependent breast cancer tumors similar to that observed
with genistein.
Carcinogenesis
2001 Oct;22(10):1667-73
Allred
CD, Ju YH, Allred KF, Chang J, Helferich WG.
Department
of Food Science and Human Nutrition and Division of Nutritional
Sciences, University of Illinois, at Urbana-Champaign, IL 61801,
USA.
The estrogenic
soy isoflavone, genistein, stimulates growth of estrogen-dependent
human breast cancer (MCF-7) cells in vivo. Genistin is the
glycoside form of genistein and the predominant form found in
plants. It is generally believed that genistin is metabolized
to the aglycone genistein in the lower gut. However, it is unclear
if the rate of metabolism of genistin to genistein is sufficient
to produce a level of genistein capable of stimulating estrogen-dependent
breast cancer cell growth. Our hypothesis was that dietary genistin
would stimulate tumor growth similar to that observed with genistein
in athymic mice. To test this hypothesis, genistin or genistein
was fed to athymic mice containing xenografted estrogen-dependent
breast tumors (MCF-7). Mice were fed either genistein at 750 p.p.m.
(parts per milllion) or genistin at 1200 p.p.m., which provides
equal molar concentrations of aglycone equivalents in both diets.
Tumor size was measured weekly for 11 weeks. At completion of
the study, half of the animals per treatment group were killed
and tumors collected for evaluation of cellular proliferation
and estrogen-responsive pS2 gene expression. Incorporation of
bromo-deoxyuridine into cellular DNA was utilized as an indicator
of cellular proliferation. Dietary genistin resulted in increased
tumor growth, pS2 expression and cellular proliferation similar
to that observed with genistein. The remaining mice were switched
to diets free of genistin and genistein. When mice were placed
on isoflavone free diets, tumors regressed over a span of 9 weeks.
Next, we examined how effectively and where metabolism of genistin
to genistein occurred in the digestive tract. We present evidence
that demonstrates conversion of genistin to its aglycone form
genistein begins in the mouth and then continues in the small
intestine. Both human saliva and the intestinal cell-free extract
from mice converted genistin to genistein. In summary, the
glycoside genistin, like the aglycone genistein, can stimulate
estrogen-dependent breast cancer cell growth in vivo. Removal
of genistin or genistein from the diet caused tumors to regress.
Soy diets containing varying amounts
of genistein stimulate growth of estrogen-dependent (MCF-7) tumors
in a dose-dependent manner.
Cancer
Res 2001 Jul 1;61(13):5045-50
Allred
CD, Allred KF, Ju YH, Virant SM, Helferich WG.
Department
of Food Science and Human Nutrition, University of Illinois, Urbana,
Illinois 61801, USA.
We have demonstrated
that the isoflavone, genistein, stimulates growth of estrogen-dependent
human breast cancer (MCF-7) cells in vivo (C. Y. Hsieh et
al., Cancer Res., 58: 3833-3838, 1998). The isoflavones are a
group of phytoestrogens that are present in high concentrations
in soy. Whether consumption of genistein from soy protein will
have similar effects on estrogen-dependent tumor growth as pure
genistein has not been investigated in the athymic mouse tumor
implant model. Depending on processing, soy protein isolates vary
widely in concentrations of genistein. We hypothesize that soy
isolates containing different concentrations of genistein will
stimulate the growth of estrogen-dependent cells in vivo in a
dose-dependent manner. To test this hypothesis we conducted experiments
in which these soy protein isolates were fed to athymic mice implanted
s.c. with estrogen-dependent tumors. Genistein content (aglycone
equivalent) of the soy isolate diets were 15, 150, or 300 ppm.
Positive (with 17beta-estradiol pellet implant) and negative (no
17beta-estradiol) control groups received casein-based (isoflavone-free)
diets. Tumor size was measured weekly. At completion of the study
animals were killed and tumors collected for evaluation of cellular
proliferation and estrogen-dependent gene expression. Incorporation
of bromodeoxyuridine into cellular DNA was used as an indicator
of cell proliferation, and pS2 mRNA was used as an estrogen-responsive
gene. Soy protein diets containing varying amounts of genistein
increased estrogen-dependent tumor growth in a dose-dependent
manner. Cell proliferation was greatest in tumors of animals given
estrogen or dietary genistein (150 and 300 ppm). Expression
of pS2 was increased in tumors from animals consuming dietary
genistein (150 and 300 ppm). Here we present new information
that soy protein isolates containing increasing concentrations
of genistein stimulate the growth of estrogen-dependent breast
cancer cells in vivo in a dose-dependent manner.
Detection of phytoestrogens in samples
of second trimester human amniotic fluid.
Toxicol
Lett 2002 Mar 28;129(3):199-205
Foster
WG, Chan S, Platt L, Hughes CL Jr.
Center
for Women's Health, Cedars-Sinai Medical Center, Los Angeles,
CA, USA. fosterw@mcmaster.ca
There is widespread
concern that fetal exposure to hormonally active chemicals may
adversely affect development of the reproductive tract. Therefore,
the present study was performed to develop the necessary analytical
methods and test the hypothesis that dietary phytoestrogens can
be quantified in second trimester human amniotic fluid. Amniotic
fluid samples (n=59) from women (n=53) undergoing routine amniocentesis
between 15 and 23 weeks of gestation were analyzed by gas chromatography/mass
spectrometric (GC/MS). Analytes included the phytoestrogens daidzein,
genistein, formononetin, biochanin A, and coumestrol. Dietary
phytoestrogens were quantified in 96.2% of second trimester amniotic
fluid samples tested. The mean (+/- standard deviation (S.D.))
concentration of daidzein and genistein in amniotic fluid was
1.44 +/- 1.34 and 1.69 +/- 1.48 ng/ml with maximum levels of 5.52
and 6.54 ng/ml, respectively. Second trimester amniotic fluid
contains quantifiable levels of dietary phytoestrogens and thus
is a marker of mid pregnancy fetal exposure.
Acute and chronic effects of genistein,
tyrphostin and lavendustin A on steroid synthesis in luteinized
human granulosa cells.
Hum
Reprod 2002 Mar;17(3):589-94
Whitehead
SA, Cross JE, Burden C, Lacey M.
Department
of Physiology, St George's Hospital Medical School, Cranmer Terrace,
London SW17 0RE, UK. s.whitehead@sghms.ac.uk
BACKGROUND:
Phytoestrogens, including genistein and other inhibitors of
tyrosine kinases (TKs), inhibit specific steroidogenic enzymes.
This study was designed to compare the effects of genistein, with
two other TK inhibitors, on steroid synthesis in human granulosa
luteal (GL) cells and to identify which steroidogenic enzymes
they may affect. METHODS: GL cells, obtained from women undergoing
IVF procedures, were cultured for various periods of time with
and without substrates for progesterone and estradiol synthesis,
in the presence or absence of the TK inhibitors. RESULTS: The
TK inhibitors significantly suppressed progesterone and estradiol
synthesis in a dose-dependent manner over a 48 h culture period.
Progesterone production in the presence of 10(-7) mol/l pregnenolone
during a 4 h period was inhibited by both acute (4 h) and chronic
(24 h) exposure of GL cells to 50 micromol/l genistein (P <
0.05) whilst no significant effects of 50 micromol/l tyrphostin
A23 were observed. Genistein (4 and 24 h exposure) inhibited the
production of estradiol using 10(-7) mol/l estrone as a substrate,
but inhibition of estradiol synthesis using androstenedione or
testosterone as substrates was only observed after a 24 h exposure.
In contrast, tyrphostin acutely stimulated estradiol synthesis
when androstenedione and testosterone were used as substrates
(P < 0.05) but not estrone. CONCLUSIONS: Genistein directly
inhibits 3 and 17beta-hydroxysteroid dehydrogenase activity, whilst
tyrphostin has an acute stimulatory effect on aromatase activity.
Over a longer time (24 and/or 48 h period), both TK inhibitors
suppress steroid synthesis.
Neonatal exposure to genistein
reduces expression of estrogen receptor alpha and androgen receptor
in testes of adult mice.
Endocr
J 2001 Dec;48(6):655-63
Shibayama
T, Fukata H, Sakurai K, Adachi T, Komiyama M, Iguchi T, Mori C.
Core
Research for Evolutional Science and Technology, Japan Science
and Technology Corporation, Kawaguchi, Saitama.
We investigated
the long-term estrogenic influence of genistein on the male reproductive
system in mice. Newborn ICR male mice were treated with genistein
(10, 100, or 1,000 microg/mouse) for neonatal 5 days. As positive
control, administration of diethylstilbestrol (0.5-50 microg/mouse)
was carried out. In mice exposed to genistein, we examined weight
of testes, sperm counts, sperm motility, and mRNA expression levels
of estrogen receptor a (ERalpha) and androgen receptor (AR) at
4, 8 or 12 weeks after birth. Moreover, at 12 weeks of age, we
evaluated protein level of ERalpha. In our conventional reproductive-toxicological
study (weight of testes, sperm counts and sperm motility), neonatal
transient exposure to genistein did not show adverse effects on
the male reproductive system in 4, 8 or 12 week old mice. However,
in mice treated with genistein mRNA expression levels of ERa and
AR were reduced at 8 weeks. This reduction was recovered at 12
weeks in mice treated with a lower dose (10 microg) of genistein
but not in those with higher doses (100 microg and 1,000 microg).
In addition, ERa protein levels tended to decrease in 12 weeks
of adulthood. Our results exhibited that the disruption of
gene expression continued for long term such as 3 months after
administration of genistein, even if no effect was found at conventional
reproductive-toxicological level. We have shown that neonatal
administration of weak estrogenic compound (genistein) affects
male reproductive organs at molecular levels in adulthood.
Dietary soy phytoestrogen effects
on brain structure and aromatase in Long-Evans rats.
Neuroreport
2001 Nov 16;12(16):3451-5
Lephart
ED, Adlercreutz H, Lund TD.
Phytoestrogens
are estrogen-like (plant-derived) molecules that protect against
age-related diseases (cardiovascular disease and osteoporosis),
hormone-dependent (breast and prostate) cancers and selectively
bind estrogen receptors. However, little is known about the influence
of phytoestrogens on brain. Using diets containing either high
phytoestrogen levels, derived from soy, or very low phytoestrogens
we quantified phytoestrogen concentrations of daidzein, genistein
and equol in brain. We found that dietary phytoestrogens: significantly
decrease body and prostate weights, do not alter brain aromatase
levels and significantly change during adulthood the structure
of the sexually dimorphic brain region (i.e. anteroventral periventricular
nucleus; AVPV) in male, but not in female rats. Since most
commercial animal diets contain significant concentrations of
phytoestrogens their influence on brain structure should be considered.
The effect of isoflavone extract ingestion,
as Trinovin, on plasma steroids in normal men.
Steroids
2002 Jan;67(1):25-9
Lewis
JG, Morris JC, Clark BM, Elder PA.
Steroid
& Immunobiochemistry Laboratory, Canterbury Health Laboratories,
Christchurch, New Zealand.
johnl2@chhlth.govt.nz
Plasma testosterone,
dihydrotestosterone, androstenedione, dehydroepiandrosterone sulfate,
androsterone and epiandrosterone sulfates, cortisol and sex hormone
binding globulin were measured in six adult men before and during
daily isoflavone extract ingestion (40 mg) in the form of Trinovin
tablets. Although modest plasma genistein levels were achieved
following three weeks of Trinovin ingestion (106-356 nmol/l) there
were no significant changes in most of the analytes tested. However
plasma levels of dihydrotestosterone showed an increase that reached
significance when combined basal levels were compared to levels
following Trinovin treatment. The results suggest that the daily
ingestion of isoflavones in the form of Trinovin (1 tablet/day),
over a short term, does not alter most plasma steroid levels.
We therefore question the value of Trinovin, at the recommended
dosage, as offering protective effects against prostate disease
by mechanisms involving either significant modulation of plasma
steroid or SHBG levels. In contrast the increase in dihydrotestosterone
plasma levels could be seen as possibly detrimental.
Oxidative metabolism and genotoxic
potential of major isoflavone phytoestrogens.
J
Chromatogr B Analyt Technol Biomed Life Sci 2002 Sep 25;777(1-2):211
Kulling
S, Lehmann L, Metzler M.
Institute
of Food Chemistry and Toxicology, University of Karlsruhe, P.O.
Box 6980, D-76128, Karlsruhe, Germany
The soy isoflavones
daidzein, genistein and glycitein are extensively metabolized
by rat liver microsomes to a variety of catechol metabolites.
Hydroxylated metabolites of daidzein and genistein have also
been demonstrated in incubations with human hepatic microsomes
and in the urine of humans after ingestion of soy food. Although
the microsomal metabolism of formononetin and biochanin A is dominated
by demethylation to daidzein and genistein, respectively, catechols
of the parent isoflavones and of the demethylation products are
also formed. Thus, oxidative metabolism appears to be common
among isoflavones and may have implications for their biological
activities. As genistein but not daidzein exhibits clastogenic
activity in cultured mammalian cells, the role of oxidative metabolism
for the genotoxicity of isoflavones is of particular interest.
Reproductive effects in male and female
rats of neonatal exposure to genistein.
Reprod
Toxicol 2001 Jul-Aug;15(4):399-411
Nagao
T, Yoshimura S, Saito Y, Nakagomi M, Usumi K, Ono H.
Department
of Reproductive and Developmental Biology, Hatano Research Institute,
Food and Drug Safety Center, Hadano, Kanagawa, Japan. nagaot@kb3.so-net.ne.jp
Sprague-Dawley
rats were administered genistein orally at doses of 12.5, 25,
50, or 100 mg/kg on postnatal days 1 through 5 to examine its
effects on reproductive function after puberty. In addition, preputial
separation and vaginal opening as endpoints of sexual maturation,
estrous cycling, sperm count, serum testosterone concentration,
and histopathologic changes of reproductive organs of male and
female rats were examined. Body weights of male and female
rats exposed to genistein at any dose level examined were lower
than those of controls. Timing of preputial separation in
males and timing of vaginal opening were not affected by genistein
treatment. The number of females showing estrous cycle irregularities
was increased by genistein treatment. The fertility of female
rats exposed neonatally to genistein at 100 mg/kg was disrupted,
while neonatal exposure to genistein did not affect male fertility.
Neither sperm counts nor serum testosterone concentration were
changed by neonatal exposure to genistein. Female rats exposed
neonatally to genistein at 100 mg/kg showed histopathologic changes
in the ovaries and uterus, while male rats showed no histopathologic
alterations in the gonads. The results of this study indicate
that early neonatal exposure to genistein caused dysfunction of
postpubertal reproductive performance as well as abnormal development
of gonads in female but not in male rats.
Developmental estrogenization and
prostatic neoplasia.
Prostate
1994;24(2):67-78
Santti
R, Newbold RR, Makela S, Pylkkanen L, McLachlan JA.
Department
of Anatomy, University of Turku, Finland.
The association
of estrogens with benign prostatic hyperplasia and prostatic cancer
has been widely studied, but no conclusive evidence exists for
a role of estrogens in prostatic disease. This paper reviews the
literature and describes studies which have sought to show a correlation
of estrogens and alterations in the prostates of humans and experimental
animal models. Using the developmentally estrogenized mouse model,
we propose an alternative role for estrogens as a predisposing
factor for prostatic diseases: estrogen exposure during development
may initiate cellular changes in the prostate which would require
estrogens and/or androgens later in life for promotion to hyperplasia
or neoplasia. Thus, the critical time for estrogen action would
be during the development of the prostatic tissue. We further
suggest that estrogen-sensitive cells may remain in the prostate
and be more responsive to estrogens later in life or less responsive
to the normal controlling mechanisms of prostatic growth.
Neurobehavioral effects of dietary
soy phytoestrogens.
Neurotoxicol
Teratol 2002 Jan-Feb;24(1):5-16
Lephart
ED, West TW, Weber KS, Rhees RW, Setchell KD, Adlercreutz H, Lund
TD.
Neuroscience
Center, 633 WIDB, Brigham Young University, Provo, UT 86402, USA.
edwinlephart@byu.edu
Phytoestrogens,
plant-derived nonsteroidal estrogens found in high abundance in
most soy food products, have been studied for their potential
beneficial effects against hormone-dependent cancers and age-related
diseases. However, little is known about the influence of phytoestrogens
on the brain or behavior. This brief review describes mainly our
own studies in rodents that have examined the influence of dietary
soy isoflavones on certain aspects of brain structure, learning,
memory and anxiety along with the brain androgen-metabolizing
enzyme, aromatase. These studies used a commercially available
diet rich in phytoestrogens (Phyto-rich) vs. a custom diet relatively
free of phytoestrogens (Phyto-free). The phytoestrogen content
of each diet was determined by high-performance liquid chromatography
analysis, circulating plasma phytoestrogen levels were quantified
by gas chromatography mass spectroscopy and concentrations of
phytoestrogens in specific brain regions were measured by time-resolved
fluoroimmunoassay (TR-FIA). Our studies showed that brain aromatase
levels were not significantly altered by phytoestrogen diet treatments
in perinatal, maternal or adult rats. However, volumes of the
sexually dimorphic nucleus of the preoptic area (SDN-POA) were
significantly affected by the Phyto-free diet treatment in male
rats during adulthood, where SDN-POA volumes were smaller compared
to Phyto-rich male values. Additionally, the Phyto-rich diet fed
to adult male and female rats produced anxiolytic effects as assessed
in the elevated plus maze vs. Phyto-free fed animals. Finally,
when learning and memory parameters were examined in a radial
arm maze testing visual-spatial memory (VSM), the diet treatments
significantly changed the typical sexually dimorphic pattern of
VSM. Specifically, adult Phyto-rich fed females outperformed Phyto-free
fed females, while in males on the same diets, the opposite pattern
of maze performance was observed. When female vs. male performance
was compared, Phyto-rich females executed the VSM task in a manner
similar to that of Phyto-free fed males, while Phyto-free fed
female's VSM was comparable to Phyto-rich males. These results
indicate that consumption of dietary phytoestrogens resulting
in very high plasma isoflavone levels (in many cases over a relatively
short interval of consumption in adulthood) can significantly
alter sexually dimorphic brain regions, anxiety, learning and
memory. The findings of these studies identify the biological
actions of phytoestrogens, specifically isoflavones and their
metabolites, found in animal soy-containing diets on brain and
behavior and implicate the importance of phytoestrogens given
the recognized significance of estrogens in brain and neural disorders,
such as Alzheimer's disease, especially in women.
Inactivation of thyroid peroxidase
by soy isoflavones, in vitro and in vivo.
J
Chromatogr B Analyt Technol Biomed Life Sci 2002 Sep 25;777(1-2):269
Doerge
D, Chang H.
Division
of Biochemical Toxicology, National Center for Toxicological Research,
3900 NCTR Road, 72079, Jefferson, AR, USA
Soy-containing
foods and dietary supplements are widely consumed for putative
health benefits (e.g. cancer chemoprevention, beneficial effects
on serum lipids associated with cardiovascular health, reduction
of osteoporosis, relief of menopausal symptoms). However, studies
of soy isoflavones in experimental animals suggest possible adverse
effects as well (e.g. enhancement of reproductive organ cancer,
modulation of endocrine function, anti-thyroid effects). This
paper reviews the evidence in humans and animals for anti-thyroid
effects of soy and its principal isoflavones, genistein and daidzein.
Estrogen
and spermatogenesis.
Endocr
Rev 2001 Jun;22(3):289-318
O'Donnell
L, Robertson KM, Jones ME, Simpson ER.
Prince
Henry's Institute of Medical Research, Victoria, Australia. liza.odonnell@med.monash.edu.au
Although it has
been known for many years that estrogen administration has deleterious
effects on male fertility, data from transgenic mice deficient
in estrogen receptors or aromatase point to an essential physiological
role for estrogen in male fertility. This review summarizes the
current knowledge on the localization of estrogen receptors and
aromatase in the testis in an effort to understand the likely
sites of estrogen action. The review also discusses the many studies
that have used models employing the administration of estrogenic
substances to show that male fertility is responsive to estrogen,
thus providing a mechanism by which inappropriate exposure to
estrogenic substances may cause adverse effects on spermatogenesis
and male fertility. The reproductive phenotypes of mice deficient
in estrogen receptors alpha and/or beta and aromatase are also
compared to evaluate the physiological role of estrogen in male
fertility. The review focuses on the effects of estrogen administration
or deprivation, primarily in rodents, on the hypothalamo-pituitary-testis
axis, testicular function (including Leydig cell, Sertoli cell,
and germ cell development and function), and in the development
and function of the efferent ductules and epididymis. The requirement
for estrogen in normal male sexual behavior is also reviewed,
along with the somewhat limited data on the fertility of men who
lack either the capacity to produce or respond to estrogen. This
review highlights the ability of exogenous estrogen exposure to
perturb spermatogenesis and male fertility, as well as the emerging
physiological role of estrogens in male fertility, suggesting
that, in this local context, estrogenic substances should also
be considered "male hormones."
The phenotype of the aromatase
knockout mouse reveals dietary phytoestrogens impact significantly
on testis function.
Endocrinology
2002 Aug;143(8):2913-21
Robertson
KM, O'Donnell L, Simpson ER, Jones ME.
Prince
Henry's Institute of Medical Research, Clayton, 3168 Victoria,
Australia.
Estrogen is synthesized
in the testis, both in Leydig cells and seminiferous epithelium,
and its importance in spermatogenesis is highlighted by the phenotype
of the aromatase knockout (ArKO) mouse. These mice are unable
to synthesize endogenous estrogens. The males develop postmeiotic
defects by 18 wk of age. We hypothesized that maintenance of spermatogenesis
in younger animals may be mediated by exogenous estrogenic substances.
Dietary soy meal, contained in almost all commercial rodent diets,
provides a source of estrogenic isoflavones. We thus investigated
spermatogenesis in wild-type and ArKO mice raised on a diet containing
soy, compared with a soy-free diet, to elucidate the biological
action of phytoestrogens on the testis. In ArKO mice, dietary
phytoestrogens could partially prevent disruptions to spermatogenesis,
in that they prevented the decline in germ cell numbers. They
also seemed to maintain Sertoli cell function, and they blocked
elevations in FSH. The impairment of spermatogenesis seen in soy-free
ArKOs occurred in the absence of a decreased gonadotropic stimulus,
suggesting that the effects of dietary phytoestrogens are independent
of changes to the pituitary-gonadal axis. Our study highlights
the importance of estrogen in spermatogenesis and shows that relatively
low levels of dietary phytoestrogens have a biological effect
in the testis.
Hot flushes and other menopausal symptoms
in relation to soy product intake in Japanese women.
Climacteric
1999 Mar;2(1):6-12
Nagata
C, Shimizu H, Takami R, Hayashi M, Takeda N, Yasuda K.
Department
of Public Health, Gifu University School of Medicine, 40 Tsukasa-machi,
Gifu 500-8705, Japan.
OBJECTIVE: To examine
the relationships between dietary intake of soy products and hot
flushes and other menopausal symptoms. METHODS: Subjects were
284 women aged 40-59 years who attended a health check-up program
provided by a general hospital in Gifu, Japan. They completed
a health questionnaire including the Kupperman test of menopausal
distress. Diet was assessed by a semiquantitative food frequency
questionnaire. RESULTS: Fermented soy product intake but not total
soy product intake was significantly negatively correlated with
hot flush severity (r = -0.16, p = 0.01) after controlling for
age and menopausal status. Neither total soy product intake nor
fermented soy product intake was significantly correlated with
menopausal index score. Estimated isoflavone intake from total
and fermented soy products was significantly lower by 15% (p =
0.02) and 19% (p = 0.01), respectively, in women with hot flushes,
compared to those without hot flushes after controlling for covariates.
CONCLUSION: The data support a hypothesis that intake of fermented
soy products alleviates the severity of hot flushes.
Early exposure to genistein exerts
long-lasting effects on the endocrine and immune systems in rats.
Mol
Med 2002 Nov;8(11):742-9
Klein
SL, Wisniewski AB, Marson AL, Glass GE, Gearhart JP.
The
W. Harry Feinstone Department of Molecular Microbiology and Immunology,
The Johns Hopkins Bloomberg School of Public Health, Baltimore,
Maryland, USA.
Background: Although
the immunologic effects of endogenous and synthetic estrogens
are well studied, few studies have examined the hormonal effects
of phytoestrogens (i.e., plant-derived estrogens) on the immune
system. The primary goal of this study was to compare the effects
of perinatal exposure with life-long exposure to genistein, an
estrogenic compound in soy, on the endocrine and immune system
in adulthood. Materials and Methods: Pregnant female rats were
exposed to no, low (5 mg/kg diet), or high (300 mg/kg diet) genistein
diets throughout gestation and lactation. At weaning, male offspring
exposed to genistein perinatally were either switched to the genistein-free
diet or remained on the genistein-dosed diets. At 70 days of age,
immune organ masses, lymphocyte subpopulations, cytokine concentrations,
and testosterone concentrations were assessed in male offspring.
Results: Data were analyzed based on the diets that males were
exposed to during gestation and lactation because life-long exposure
to genistein had no additional effect on any of the dependent
measures. Relative thymus masses were greater among males exposed
to the high genistein diet than among males exposed to no genistein.
Although the proportions of splenic and thymic CD4+ T cells were
not altered by genistein, the percentages of CD4+CD8+ thymocytes,
CD8+ splenocytes, and total T cells in the spleen were higher
and the percentages of CD4-CD8- thymocytes were lower among males
exposed to genistein than among males not exposed to genistein.
Synthesis of interferon-gamma (IFN-gamma) was marginally higher
and testosterone concentrations were lower among genistein-exposed
than genistein-free males. Discussion: These data illustrate
that exposure to genistein during pregnancy and lactation exerts
long-lasting effects on the endocrine and immune systems in adulthood.
Whether exposure to phytoestrogens during early development affects
responses to infectious or autoimmune diseases, as well as cancers,
later in life requires investigation.
Exposure to Genistein During Gestation
and Lactation Demasculinizes the Reproductive System in Rats.
J
Urol 2003 Apr;169(4):1582-1586
Wisniewski
AB, Klein SL, Lakshmanan Y, Gearhart JP.
PURPOSE: Exposure
to the phytoestrogen genistein (Indofine Chemical Co., Somerville,
New Jersey) can disrupt normal male sexual differentiation.
To determine if perinatal (that is gestation and lactation) genistein
exposure at doses common in human diets alters masculinization
we examined the development of the external genitalia, testes,
wolffian ducts and sexual behavior in male rats exposed to genistein
supplemented diets during early development. MATERIALS AND METHODS:
Female rats were fed a phytoestrogen-free diet supplemented with
no genistein (free), a low genistein dose (low) or a high genistein
dose (high) throughout gestation and lactation. Anogenital distance
of male offspring was measured weekly from postnatal days 2 to
21. At puberty (postnatal day 40 to 45) preputial separation,
and testis length and width of male offspring were measured. At
age 70 days reproductive organ masses, plasma testosterone concentration,
sperm counts and sexual behavior were assessed in male offspring.
RESULTS: Exposure to genistein resulted in temporary, prepubertal
urogenital abnormalities at postnatal days 21 and 40. Males
exposed to genistein had smaller anogenital distance and testis
size, and delayed preputial separation. Perinatal exposure to
genistein also caused long-term dysfunction in reproductive behavior,
in which adult males exposed to genistein were less likely to
mount, intromit and ejaculate during mating tests. Males exposed
to genistein also had lower testosterone concentrations in adulthood.
CONCLUSIONS: Perinatal genistein exposure results in transient
and lasting alterations in masculinization of the reproductive
system. These results extend our knowledge of the effects of early
genistein exposure on male development and may have implications
for human health in terms of potential relationships of endocrine
disrupters and urogenital abnormalities thought to be increasing
in incidence in boys and men.
The soya isoflavone content of rat
diet can increase anxiety and stress hormone release in the male
rat.
Psychopharmacology
(Berl) 2003 Mar 5;
Hartley
DE, Edwards JE, Spiller CE, Alom N, Tucci S, Seth P, Forsling
ML, File SE.
Psychopharmacology
Research Unit, Centre for Neuroscience, Hodgkin Building, Kings
College London, Guy's Campus, SE1 1UL, London, UK.
RATIONALE. Most
commercial rodent diets are formulated with soya protein and therefore
contain soya isoflavones. Isoflavones form one of the main
classes of phytoestrogens and have been found to exert both oestrogenic
and anti-oestrogenic effects on the central nervous system. The
effects have not been limited to reproductive behaviour, but include
effects on learning and anxiety and actions on the hypothalamo-pituitary
axis. It is therefore possible that the soya content of diet could
have significant effects on brain and behaviour and be an important
source of between-laboratory variability. OBJECTIVES. To determine
whether behaviour in two animal tests of anxiety, and stress hormone
production, would differ between rats that were fed a diet which
was free of soya isoflavones and other phytoestrogens (iso-free)
and those that were fed a diet which contained 150 &mgr;g/g
of the isoflavones genistein and daidzein (iso-150). This controlled
diet has an isoflavone concentration similar to that in the maintenance
diet routinely used in our institution. METHODS. Male rats were
randomly allocated to the iso-free and iso-150 diets and their
body weights and food and water consumption were recorded for
14 days. They were then maintained on the same diets, but housed
singly for 4 days, before testing in the social interaction and
elevated plus-maze tests of anxiety. Corticosterone concentrations
in both dietary groups were determined under basal conditions
and after the stress of the two tests of anxiety. Vasopressin
and oxytocin concentrations were determined after brief handling
stress. RESULTS. The groups did not differ in food or water intake,
body weight or oxytocin concentrations. Compared with the rats
fed the iso-free diet, the rats fed the iso-150 diet spent significantly
less time in active social interaction and made a significantly
lower percentage of entries onto the open arms of the plus-maze,
indicating anxiogenic effects in both animal tests. The groups
did not differ in their basal corticosterone concentrations, but
the iso-150 group had significantly elevated stress-induced corticosterone
concentrations. Stress-induced plasma vasopressin concentrations
were also significantly elevated in the iso-150 diet group compared
with the iso-free rats. CONCLUSIONS. Major changes in behavioural
measures of anxiety and in stress hormones can result from the
soya isoflavone content of rat diet. These changes are as striking
as those seen following drug administration and could form
an important source of variation between laboratories.
Effects of Genistein
Isoflavone (4',5',7-Trihydroxyisoflavone) and Dexamethasone on
Functional Characteristics of Spermatozoa.
J
Med Food 2001 Spring;4(1):39-47
Kumi-Diaka
J, Townsend J.
Florida
Atlantic University, Department of Biological Sciences, College
of Liberal Arts and Sciences, 2912 College Avenue, Davie, FL 33314.
Caudal epididymal
spermatozoa were used to study the influence of genistein isoflavone
and dexamethasone (dxm) on the functional characteristics of spermatozoa.
The effects of genistein alone and in combination with dxm on
sperm motility, sperm morphology, spontaneous acrosome reaction
(AcR), and ionophore A23187-induced AcR were investigated. The
FITC-PSA/Hoechst 33258 staining procedure was used to assess sperm
cell viability and AcR status and thus to differentiate between
true AcR and acrosome degeneration. The overall results indicated
that (1) lower doses of genistein alone, or in combination with
dxm, did not significantly influence sperm motility or sperm morphology;
(2) ionophore A23187 induced AcR in rat spermatozoa; (3) there
appeared to be no direct correlation between sperm motility and
AcR, (4) higher doses of genistein, alone or in combination
with dxm, significantly interfered with percentage sperm motility
and caused significant detachment of sperm heads but did not cause
morphological defects; and (5) higher doses of genistein caused
significant decrease in sperm acrosome reactivity with long duration
of exposure. In view of the fact that sperm capacitation and
AcR are physiological prerequisites for successful fertilization
of oocytes, the findings suggest that chronic exposure of spermatozoa
to high doses of genistein could be associated with infertility
problems through suppression/inhibition of AcR and sperm motility.
Dexamethasone did not appear to influence the effect of genistein
on the functionality of postspermatogenic spermatozoa.
Cytotoxic potential of the phytochemical
genistein isoflavone (4',5',7-trihydroxyisoflavone) and certain
environmental chemical compounds on testicular cells.
Biol
Cell 1999 Sep;91(7):515-23
Kumi-Diaka
J, Nguyen V, Butler A.
Florida
Atlantic University, Department of Biology, College of Liberal
Arts & Sciences, Davie 33314, USA.
The effects of
genistein (Gn), sodium azide (naz), and dexamethasone (dxm) on
testicular cells TM3, TM4 and GC-1 spg were studied in vitro.
First, a series of experiments were performed to assess the response
of the cells to the exposure of Gn, naz, dxm, a combination of
Gn with naz and Gn with dxm. Trypan blue exclusion assay was used
to determine the percentage of viability, and LDH-cytotoxicity
test was used to assess the degree of treatment-induced cytotoxicity
on each cell type. A second series of experiments were performed
to study cytomorphology and determine the type and percentage
of treatment-induced cell death (apoptosis and necrosis) on each
cell line, using fluorescent dye technique to detect apoptotic
and necrotic cells, and tunnel assay to confirm apoptosis. The
results from the data obtained demonstrated: i) that incubation
of testis cells with each of the agents (Gn, dxm, naz) alone and
in two combinations (Gn-dxm, and Gn-naz) induced significant testicular
cell death; ii) that both genistein and dexamethasone mostly and
significantly induced apoptotic cell death while sodium azide
induced necrotic cell death; iii) that addition of dexamethasone
to genistein demonstrated synergism in apoptosis on testis cells;
and iv) that combination of naz with Gn demonstrated synergism
in necrosis on testis cells even though Gn alone did not induce
significant necrosis. It is concluded that the synergistic
actions of genistein and dxm, and of genistein + sodium azide
in induction of apoptosis and/or necrosis may be of clinical and
pathophysiological research interest considering the chemopreventive
and chemotherapeutic potential of genistein; and the clinico-pharmacological
application of dexamethasone and sodium azide.
Influence of genistein (4',5,7-trihydroxyisoflavone)
on the growth and proliferation of testicular cell lines.
Biol
Cell 1998 Jul;90(4):349-54
Kumi-Diaka
J, Rodriguez R, Goudaze G.
Florida
Atlantic University, Department of Biology, College of Liberal
Arts & Sciences, Davie 33314, USA.
The effects of
genistein on testicular cells, TM3, TM4, and GC-1 spg, were studied
in vitro. First, each cell line was cultured with pre-determined
concentrations of genistein for a maximum of 72 h to assess the
effects of genistein on in vitro growth of the test cells. A second
series of experiments were performed to determine the degree of
genistein-induced apoptosis in these cells, using Apop-Tag kit
reagents, to detect apoptotic cells in situ by specific end labeling,
and detection of DNA fragments produced by the apoptotic process.
The results obtained indicate that: i) genistein inhibits the
growth and proliferation of testicular cells; ii) growth inhibition
and proliferation is dose- and exposure-time dependent; iii) there
is significant difference in sensitivity of the different testicular
cells to genistein; iv) genistein induces apoptosis in testicular
cells in a concentration-dependent manner. Genistein-induced
apoptosis identifies genistein as a potential diagnostic and therapeutic
tool in testicular pathophysiological research.
Impact of exposure to endocrine
disrupters in utero and in childhood on adult reproduction.
Best
Pract Res Clin Endocrinol Metab 2002 Jun;16(2):289-309
Norgil
Damgaard I, Main KM, Toppari J, Skakkebaek NE.
Department
of Growth and Reproduction, Copenhagen University Hospital, Rigshospitalet,
Blegdamsvej 9, 2100, Copenhagen, Denmark.
Recent reports
have demonstrated a decline in human male reproductive health:
high and probably increasing prevalence of cryptorchidism and
hypospadias, low and probably decreasing semen quality, a rising
incidence of testicular cancer and a growing demand for assisted
reproduction. These changes seem to be interrelated and may
be symptoms of a common underlying entity, the testicular dysgenesis
syndrome, with foundations in fetal life due to adverse environmental
influences. Wildlife experience and animal studies have provided
evidence that fetal or perinatal exposure to endocrine disrupters
results in disturbed sexual differentiation and urogenital malformations
followed by decreased reproductive health in adult life. This
chapter reviews existing evidence for a connection between (i)
exposure to endocrine disrupters in fetal life and childhood and
(ii) adult reproductive health in humans. This topic is not only
relevant to basic scientists but also to clinical endocrinologists,
who should also be encouraged to participate in research concerning
this problem.
Regulation of male sex hormone levels
by soy isoflavones in rats.
Nutr
Cancer 2002;42(2):206-10
Yi MA,
Son HM, Lee JS, Kwon CS, Lim JK, Yeo YK, Park YS, Kim JS.
Department
of Animal Science and Biotechnology, Kyungpook National University,
Taegu 702-701, South Korea.
Several studies
have suggested that soybean intake is associated with a lower
risk of prostate cancer. However, the mechanism of prostate cancer
prevention by soybeans remains unclear. Because prostate cancer
is reported to have an association with an increased level of
dihydrotestosterone (DHT) and soybean isoflavones are known to
inhibit 5 alpha-reductase, which is involved in the conversion
of testosterone to DHT, the effects of soybean extract and isoflavones
on the plasma levels of male sex hormones were investigated using
male rats. In Experiment I, Sprague-Dawley rats were fed diets
with and without soy flour; in Experiment II, rats were fed diets
containing 2% soy methanol extract or 0.2% semipurified isoflavones
or a control diet. The study showed a reduction of plasma DHT
along with an increase in total plasma androgen in rats fed soy
flour or semipurified isoflavones for 1 wk. These results suggest
that soy isoflavone intake may reduce plasma DHT level.
Dietary soy and increased risk of bladder
cancer: the Singapore Chinese Health Study.
Cancer
Epidemiol Biomarkers Prev. 2002 Dec;11(12):1674-7.
Sun CL,
Yuan JM, Arakawa K, Low SH, Lee HP, Yu MC.
USC/Norris
Comprehensive Cancer Center, University of Southern California
Keck School of Medicine, Los Angeles, California 90089, USA. canlan@hsc.usc.edu
The association
between soyfood consumption and subsequent bladder cancer risk
was investigated in a population-based cohort study, the Singapore
Chinese Health Study. As of December 31, 2000, 329,848 person-years
of follow-up were accrued. Sixty-one histologically confirmed
incident bladder cancer cases were identified. Information on
soyfood consumption at baseline was obtained through in-person
interviews using a validated dietary questionnaire. Relative risks
and 95% confidence intervals were calculated using the Cox proportional
hazard regression method. High intake of soyfood was statistically
significantly related to an elevated risk of bladder cancer.
Relative to the lowest quartile of energy-adjusted total soy intake
(<36.9 g/1000 Kcal), the highest quartile of total soy intake
(> or =92.5 g/1000 Kcal) was associated with a 2.3-fold increase
in bladder cancer risk (95% confidence interval = 1.1-5.1) after
adjustment for cigarette smoking and level of education. Similar
results were obtained for intakes of soy protein and soy isoflavones.
The soyfood-bladder cancer risk association did not differ
significantly between men and women and was not explained by other
dietary factors. The soy-cancer relationship became stronger when
the analysis was restricted to subjects with longer (> or =3
years) duration of follow-up. To our knowledge, this is the
first epidemiological report on the effect of dietary soy on bladder
cancer risk.
Phytoestrogen supplements for the treatment
of hot flashes: the Isoflavone Clover Extract (ICE) study: a randomized
controlled trial.
JAMA.
2003 Jul 9;290(2):207-14.
Tice JA,
Ettinger B, Ensrud K, Wallace R, Blackwell T, Cummings SR.
Division
of General Internal Medicine, Department of Medicine, University
of California, San Francisco 94143, USA.
CONTEXT: Clinical
trials demonstrating increased risk of cardiovascular disease
and breast cancer among women randomized to hormone replacement
therapy have increased interest in other therapies for menopausal
symptoms. Dietary supplements containing isoflavones are widely
used as alternatives to hormonal therapies for hot flashes, but
there is a paucity of data supporting their efficacy. OBJECTIVE:
To compare the efficacy and safety of 2 dietary supplements derived
from red clover with placebo in symptomatic menopausal women.
DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind, placebo-controlled
trial of menopausal women, aged 45 to 60 years, who were experiencing
at least 35 hot flashes per week. The study was conducted between
November 1999 and March 2001 at 3 US medical centers and included
women who were recently postmenopausal (mean [SD], 3.3 [4.5] years
since menopause) experiencing 8.1 hot flashes per day. Women were
excluded if they were vegetarians, consumed soy products more
than once per week, or took medications affecting isoflavone absorption.
INTERVENTION: After a 2-week placebo run-in, 252 participants
were randomly assigned to Promensil (82 mg of total isoflavones
per day), Rimostil (57 mg of total isoflavones per day), or an
identical placebo, and followed-up for 12 weeks. MAIN OUTCOME
MEASURE: The primary outcome measure was the change in frequency
of hot flashes measured by participant daily diaries. Secondary
outcome measures included changes in quality of life and adverse
events. RESULTS: Of 252 participants, 246 (98%) completed the
12-week protocol. The reductions in mean daily hot flash count
at 12 weeks were similar for the Promensil (5.1), Rimostil (5.4),
and placebo (5.0) groups. In comparison with the placebo group,
participants in the Promensil group (41%; 95% confidence interval
[CI], 29%-51%; P =.03), but not in the Rimostil group (34%; 95%
CI, 22%-46%; P =.74) reduced hot flashes more rapidly. Quality-of-life
improvements and adverse events were comparable in the 3 groups.
CONCLUSION: Although the study provides some evidence for a
biological effect of Promensil, neither supplement had a clinically
important effect on hot flashes or other symptoms of menopause.
Dietary topoisomerase II-poisons:
contribution of soy products to infant leukemia?
EXCLI
Journal 2002;1:8-14
Jan G.
Hengstler, Carolin K. Heimerdinger1, Ilka B. Schiffer1, Susanne
Gebhard1, Jens Sagemüller1, Berno Tanner2, Hermann M. Bolt3, Franz
Oesch1
Institute of Legal Medicine, Department of Molecular Toxicology,
University of Leipzig, Johannisallee 28, 04103 Leipzig, Germany,
Telephone: 0049 6131 231721, Fax: 0049 6131 230506, 1Institute
of Toxicology and 2Department of Gynecology, University of Mainz,
Obere Zahlbacher Str. 67, 55131 Mainz, Germany, 3Institute of
Occupational Physiology at the University of Dortmund; Ardeystraße
67, D- 44139 Dortmund, Germany
DNA topoisomerases
are nuclear enzymes inducing transient breaks in the DNA allowing
DNA strands or double helices to pass through each other. The
clinically used DNA topoisomerase II-poison etoposide is known
to induce DNA double strand breaks leading to chromosomal aberrations
and leukemias. Recently, some alarming studies have been published,
suggesting that maternal exposure to low doses of dietary topoisomerase
II poisons, including bioflavonoids such as genistein or quercetin,
may contribute to the development of infant leukemia: approximately
80% of infants with acute myelogenous leukemia (AML) and acute
lymphoblastic leukemia (ALL) have chromosome translocations involving
the MLL (mixed lineage leukemia) gene. It has been shown that
antineoplastic chemotherapy with the leukemogenic topoisomerase
II-poison etoposide induced identical chromosomal aberrations
involving the MLL gene compared to children with infant leukemia.
Interestingly, the MLL cleavage sites induced by etoposide colocalized
with the cleavage sites observed in infant leukemia. In addition,
an almost 10-fold higher risk of infant AML has been reported
for mothers consuming relatively high levels of topoisomerase
II-poison containing foods. These observations are relevant,
since many foods contain topoisomerase IIpoisons, predominantly
soy and soy products, but also coffee, wine, tea, cocoa, as well
as some fruits and vegetables. Further studies on the role
of dietary topoisomerase II-poisons are urgently required. If
the causal relationship between dietary exposure to topoisomerase
IIpoisons and infant leukemia will be confirmed, care should be
taken to reduce exposure to critical foods during pregnancy.
Full Paper Available Here
Effect of soy-derived isoflavones
on hot flushes, endometrial thickness, and the pulsatility index
of the uterine and cerebral arteries.
Fertil
Steril 2003 May;79(5):1112-1117
Penotti
M, Fabio E, Modena AB, Rinaldi M, Omodei U, Vigano P.
Second
Department of Obstetrics and Gynecology of the University of Milan,
Milan, Italy
To determine the
effect of soy-derived isoflavones on hot flushes, endometrial
thickness, and the vascular reactivity of uterine and cerebral
arteries. Double-blind, randomized, placebo-controlled trial.Healthy
volunteers in an academic research environment.Sixty-two postmenopausal
women aged 45-60 years attending the Outpatient Menopause Clinic
of our gynecological departments. The patients were administered
72 mg of soy-derived isoflavones or placebo under double-blind
conditions. The daily number of hot flushes was recorded in a
diary. Endometrial thickness was measured by means of transvaginal
ultrasound; the uterine, internal carotid, and middle cerebral
arteries were evaluated using Doppler ultrasound. The daily number
of hot flushes, endometrial thickness, and arterial pulsatility
index (PI). Both treatments led to a 40% reduction in the number
of hot flushes. Soy-derived isoflavones had no effect on endometrial
thickness or the PI of the uterine and cerebral arteries. The
daily administration of 72 mg of soy-derived isoflavones is no
more effective than placebo in reducing hot flushes in postmenopausal
women. It also has no effect on endometrial thickness or the PI
of the uterine and cerebral arteries.
Dietary supplements of soya
flour lower serum testosterone concentrations and improve markers
of oxidative stress in men.
Eur
J Clin Nutr 2003 Jan;57(1):100-6
Gardner-Thorpe
D, O'Hagen C, Young I, Lewis SJ.
Department of Medicine, University Hospital of Wales, Cardiff,
Wales, UK.
OBJECTIVE:: We
examined the effects on serum sex steroids, lipids and markers
of oxidative stress of supplementing the diets of healthy male
volunteers with scones made with soya flour. DESIGN:: A randomized
placebo controlled cross-over trial. SETTING:: University Hospital
of Wales. SUBJECTS:: Twenty volunteers recruited by advertisement.
INTERVENTIONS:: Male volunteers ate three scones a day in addition
to their normal diet for a period of 6 weeks. The scones were
made with either wheat or soya flour (containing 120 mg/day of
isoflavones). Blood was analysed for sex steroids (testosterone,
dihydro-testosterone, oestradiol, oestrone, sex hormone binding
globulin, albumin and the concentration of non-protein bound sex
steroids were calculated), lipid profile (total cholesterol, high
density lipoprotein cholesterol and triglycerides) and measures
of oxidative stress (hydroperoxides, susceptibility of LDL to
oxidation with copper and myeloperoxidase). RESULTS:: The volunteers'
mean age was 35.6 (s.d. 11.2) y. Total serum testosterone fell
in volunteers taking the soya scones (19.3-18.2 nmol/l; 95% CI
1.01, 1.12; P=0.03). No significant changes were seen in the
concentrations of the other serum sex steroids, albumin or sex
hormone binding globulin throughout the study. Significant improvements
in two of the three markers of oxidative stress were seen in volunteers
taking soya scones. Lag time for myeloperoxidase rose from 55.0
to 68.0 min (95% CI -16.0, -3.5; P=0.009) and the presence of
hydroperoxides decreased from 2.69 to 2.34 micro mol/l (95% CI
0.12, 0.71; P=0.009). There were no changes seen in serum triglycerides
or cholesterol. CONCLUSIONS:: We have shown that soya supplements
reduce serum testosterone and improve markers of oxidative stress.
These findings provide a putative mechanism by which soya supplements
could protect against prostatic disease and atherosclerosis. Further
dietary studies with clinical end points are warranted. SPONSORSHIP::
The Mason medical research foundation.
Maternal exposure to potential inhibitors
of DNA topoisomerase II and infant leukemia (United States): a
report from the Children's Cancer Group.
Cancer
Causes Control. 1996 Nov;7(6):581-90.
Ross JA,
Potter JD, Reaman GH, Pendergrass TW, Robison LL.
Division of Pediatric Epidemiology and Clinical Research, University
of Minnesota, Minneapolis, USA.
Nearly 80 percent
of infant leukemias present with an abnormality involving the
MLL gene at 11q23. Moreover, secondary acute myeloid leukemias
(AML) that occur as the result of chemotherapy agents, which are
known to inhibit DNA topoisomerase II, often manifest the same
MLL abnormalities. It has been hypothesized that de novo infant
leukemias may occur as a result of maternal exposure to agents
in diet and medications that inhibit DNA topoisomerase II.
Three epidemiologic studies of childhood leukemia with similar
methodologies were conducted in the United States and Canada over
the past 10 years by the Children's Cancer Group (CCG). Of the
total 771 mothers of infants diagnosed at one year of age or less
(< 12.5 months) who originally were interviewed (303 infant
cases and 468 matched controls) across the three studies, follow-up
questionnaire data on maternal exposure to potential DNA topoisomerase
II inhibitors during pregnancy were available on 84 cases and
97 matched controls in the US. For maternal diet, a composite
variable was created that consisted of 10 foods identified alpha
priori as containing DNA topoisomerase II inhibitors. There were
no significant trends with increasing maternal consumption for
either the overall group, or the acute lymphoblastic leukemia
(ALL) stratum. However, within the AML stratum, there was a
statistically significant positive association (P trend = 0.04)
with increasing consumption of DNA topoisomerase II-inhibitor
containing foods (odds ratio [OR] = 9.8, 95 percent confidence
interval [CI] = 1.1-84.8; OR = 10.2, CI = 1.1-96.4; for medium
and high consumption, respectively). Other potential topoisomerase
II inhibitors were explored; no significant findings were found.
Results of this preliminary study, in combination with molecular
data, should be used in future investigations of childhood leukemia
(particularly, infant) to justify the incorporation of a detailed
dietary history.
The phytoestrogens coumoestrol and
genistein induce structural chromosomal aberrations in cultured
human peripheral blood lymphocytes.
Arch
Toxicol. 1999 Feb;73(1):50-4.
Kulling
SE, Rosenberg B, Jacobs E, Metzler M.
Institute of Food Chemistry, University of Karlsruhe, Germany.
The clastogenic
potential of the phytoestrogens coumoestrol (COUM), genistein
(GEN) and daidzein (DAI) has been studied in human peripheral
blood lymphocytes in vitro. After exposure of the cultured lymphocytes
to 50 to 75 microM COUM or 25 microM GEN for 6 h, a clear induction
of structural chromosomal aberrations was observed by cytogenetic
analysis. The major alterations were chromatid breaks, gaps and
interchanges. In contrast, DAI did not induce chromosome aberrations
even at 100 microM. These results, together with previously
published reports on the induction of micronuclei and DNA strand
breaks in cultured Chinese hamster V79 cells by COUM and GEN,
but not DAI, suggest that some but not all phytoestrogens have
the potential for genetic toxicity.
Cell-transforming activity and mutagenicity
of 5 phytoestrogens in cultured mammalian cells.
Int
J Cancer 2003 Jun 20;105(3):312-20
Tsutsui
T, Tamura Y, Yagi E, Someya H, Hori I, Metzler M, Barrett JC.
Department of Pharmacology, The Nippon Dental University, School
of Dentistry at Tokyo, Tokyo, Japan.
For the simultaneous
assessment of in vitro carcinogenicity and mutagenicity of phytoestrogens,
the abilities of 5 phytoestrogens, daidzein, genistein, biochanin
A, prunetin, and coumestrol, to induce cell transformation and
genetic effects were examined using the Syrian hamster embryo
(SHE) cell model. Cellular growth was inhibited by all phytoestrogens
in a concentration-related manner. The growth inhibitory effect
of the compounds was ranked: genistein, prunetin > coumestrol
> biochanin A > daidzein, which did not correspond to their
apoptosis-inducing abilities. Morphological transformation
in SHE cells was elicited by all phytoestrogens, except, prunetin.
The transforming activities were ranked as follows: genistein
> coumestrol > daidzein > biochanin A. Somatic mutations
in SHE cells at the Na(+)/K(+) ATPase and hprt loci were induced
only by genistein, coumestrol, or daidzein. Chromosome aberrations
were induced by genistein or coumestrol, and aneuploidy in the
near diploid range was occurred by genistein or biochanin A. Genistein,
biochanin A or daidzein induced DNA adduct formation in SHE cells
with the abilities: genistein > biochanin A > daidzein.
Prunetin was negative for any of these genetic endpoints.
Our results provide evidence that genistein, coumestrol, daidzein
and biochanin A induce cell transformation in SHE cells and that
the transforming activities of these phytoestrogens correspond
to at least 2 of the mutagenic effects by each phytoestrogen,
i.e., gene mutations, chromosome aberrations, aneuploidy or DNA
adduct formation, suggesting the possible involvement of mutagenicity
in the initiation of phytoestrogen-induced carcinogenesis.
A pilot study of the effects of phytoestrogen
supplementation on postmenopausal endometrium.
J
Soc Gynecol Investig 2002 Jul-Aug;9(4):238-42
Balk JL,
Whiteside DA, Naus G, DeFerrari E, Roberts JM.
Department of Obstetrics, Gynecology, and Reproductive Sciences,
Magee-Womens Hospital, University of Pittsburgh, Pennsylvania
15213, USA.
OBJECTIVE: This
study was designed to assess endometrial histology in postmenopausal
women not taking hormone replacement therapy, to evaluate side
effects and efficacy of phytoestrogens in treating menopause-associated
symptoms, and to determine whether 6 months of phytoestrogen supplementation
altered endometrial histology. METHODS: We performed a prospective,
double-blinded, randomized, placebo-controlled trial comparing
the effects of 6 months of dietary phytoestrogen supplementation
versus placebo in postmenopausal women. Baseline endometrial
biopsies were performed and, if adequate, nonhyperplastic, noncancerous,
and nonovulatory, subjects were randomly assigned to receive daily
placebo or soy cereal supplementation for 6 months. Study subjects
completed baseline and weekly dietary, symptom, and side effect
logs. Repeat endometrial biopsies were obtained at 6 months. RESULTS:
Subjects were recruited from January 1998 through June 2000. Twenty-seven
subjects were randomized, and 19 completed the study. One (3.7%)
baseline endometrial sample was weakly proliferative. All other
baseline and final biopsies were consistent with atrophic, inactive
endometrium. The maximum risk of endometrial stimulation with
phytoestrogens is 35%. Hot flushes, night sweats, and vaginal
dryness were significantly less severe at the final week of the
study compared with baseline in the placebo group. Insomnia was
more common in the treated group. There were no other statistically
significant differences in symptoms or side effects. CONCLUSION:
Phytoestrogens did not cause stimulation of the endometrium. Insomnia
was more frequent over the 6-month study in the soy group, whereas
hot flushes, night sweats, and vaginal dryness improved from baseline
in the placebo group but not in the soy group.
Soya phytoestrogens change cortical
and hippocampal expression of BDNF mRNA in male rats.
Neurosci Lett. 2003 Feb 27;338(2):135-8.
File SE,
Hartley DE, Alom N, Rattray M.
Psychopharmacology Research Unit and Biochemical Neuropharmacology
Group, Centre for Neuroscience Research, King's College London,
Hodgkin Building, Guy's Campus, SE1 1UL, London, UK.
Adult
male hooded Lister rats were either fed a diet containing 150
microg/g soya phytoestrogens or a soya-free diet for 18 days.
This concentration of phytoestrogens should have been sufficient
to occupy the oestrogen-beta, but not the oestrogen-alpha, receptors.
Using in situ hybridisation, significant reductions were found
in brain-derived neurotrophic factor (BDNF) mRNA expression in
the CA3 and CA4 region of the hippocampus and in the cerebral
cortex in the rats fed the diet containing phytoestrogens, compared
with those on the soya-free diet. No changes in glutamic acid
decarboxylase-67 or glial fibrillary acidic protein mRNA were
found. This suggests a role for oestrogen-beta receptors in regulating
BDNF mRNA expression.
This
abstract should be read in conjunction with that of Connor
et al. 1997 below.
Brain-derived neurotrophic factor
is reduced in Alzheimer's disease.
Brain
Res Mol Brain Res. 1997 Oct 3;49(1-2):71-81.
Connor
B, Young D, Yan Q, Faull RL, Synek B, Dragunow M.
Department of Pharmacology, Faculty of Medicine and Health Science,
University of Auckland, New Zealand.
Alzheimer's disease
may be due to a deficiency in neurotrophin protein or receptor
expression. Consistent with this hypothesis, a reduction in
BDNF mRNA expression has been observed in human post-mortem Alzheimer's
disease hippocampi. To further investigate this observation,
we examined whether the alteration in BDNF expression also occurred
at the protein level in human post-mortem Alzheimer's disease
hippocampi and temporal cortices using immunohistochemical techniques.
We observed a reduction in the intensity and number of BDNF-immunoreactive
cell bodies within both the Alzheimer's disease hippocampus and
temporal cortex when compared to normal tissue. These results
support and extend previous findings that BDNF mRNA is reduced
in the human Alzheimer's disease hippocampus and temporal cortex,
and suggest that a loss of BDNF may contribute to the progressive
atrophy of neurons in Alzheimer's disease.
Brain Aging and Midlife Tofu Consumption
Journal
of the American College of Nutrition, Vol. 19, No. 2, 242-255
(2000)
Lon R.
White, MD, MPH,,,, Helen Petrovitch, MD,, G. Webster Ross, MD,,
Kamal Masaki, MD,, John Hardman, MD, James Nelson, MD, Daron Davis,
MD and William Markesbery, MD
Objective:
To examine associations of midlife tofu consumption with brain
function and structural changes in late life.
Methods:
The design utilized surviving participants of a longitudinal study
established in 1965 for research on heart disease, stroke, and
cancer. Information on consumption of selected foods was available
from standardized interviews conducted 1965–1967 and 1971–1974.
A 4-level composite intake index defined "low-low" consumption
as fewer than two servings of tofu per week in 1965 and no tofu
in the prior week in 1971. Men who reported two or more servings
per week at both interviews were defined as "high-high"
consumers. Intermediate or less consistent "low" and
"high" consumption levels were also defined. Cognitive
functioning was tested at the 1991–1993 examination, when participants
were aged 71 to 93 years (n=3734). Brain atrophy was assessed
using neuroimage (n=574) and autopsy (n=290) information. Cognitive
function data were also analyzed for wives of a sample of study
participants (n=502) who had been living with the participants
at the time of their dietary interviews.
Results:
Poor cognitive test performance, enlargement of ventricles
and low brain weight were each significantly and independently
associated with higher midlife tofu consumption. A similar
association of midlife tofu intake with poor late life cognitive
test scores was also observed among wives of cohort members, using
the husband’s answers to food frequency questions as proxy for
the wife’s consumption. Statistically significant associations
were consistently demonstrated in linear and logistic multivariate
regression models. Odds ratios comparing endpoints among "high-high"
with "low-low" consumers were mostly in the range of
1.6 to 2.0.
Conclusions: In this population, higher midlife tofu consumption
was independently associated with indicators of cognitive impairment
and brain atrophy in late life.
Full Paper
Here
Aluminum and bone disorders: with
specific reference to aluminum contamination of infant nutrients.
J
Am Coll Nutr. 1988 Jun;7(3):199-214.
Koo WW,
Kaplan LA.
Department of Pediatrics, University of Alberta, Edmonton, Canada.
Aluminum (Al)
impairment of bone matrix formation and mineralization may be
mediated by its direct effect on bone cells or indirectly by its
effect on parathyroid hormone and calcium metabolism. Its toxic
effects are proportional to tissue Al load. Al contamination of
nutrients depends on the amount of Al present naturally in chemicals
or from the manufacturing process. Intravenous calcium, phosphorus,
and albumin solutions have high Al (greater than 500 micrograms/L),
whereas crystalline amino acid, sterile water, and dextrose water
have low Al (less than 50 micrograms/L) content. Enteral nutrients
including human and whole cow milk have low Al, whereas highly
processed infant formulas with multiple additives, such as soy
formula, preterm infant formula, and formulas for specific disorders
are heavily contaminated with Al. Healthy adults are in zero
balance for Al. The gastrointestinal tract excludes greater than
95% of dietary Al, and kidney is the dominant organ for Al excretion.
However, even with normal renal function, only 30-60% of an
Al load from parenteral nutrition is excreted in the urine, resulting
in tissue accumulation of Al. The risk for Al toxicity is
greatest in infants with chronic renal insufficiency, recipients
of long term parenteral nutrition, i.e., no gut barrier to Al
loading, and preterm infants with low Al binding capacity. The
rapid growth of the infant would theoretically potentiate Al toxicity
in all infants, although the critical level of Al loading causing
bone disorders is not known. To minimize tissue burden, Al
content of infant nutrients should be similar to "background"
levels, i.e., similar to whole milk (less than 50 micrograms/L).
Severe nutritional deficiencies
in toddlers resulting from health food milk alternatives.
Pediatrics. 2001 Apr;107(4):E45.
Carvalho
NF, Kenney RD, Carrington PH, Hall DE.
Scottish Rite Pediatric and Adolescent Consultants, Childrens
Healthcare of Atlanta, Atlanta, Georgia 30342-1600, USA. drnorm@aol.com
It is widely appreciated
that health food beverages are not appropriate for infants. Because
of continued growth, children beyond infancy remain susceptible
to nutritional disorders. We report on 2 cases of severe nutritional
deficiency caused by consumption of health food beverages. In
both cases, the parents were well-educated, appeared conscientious,
and their children received regular medical care. Diagnoses were
delayed by a low index of suspicion. In addition, nutritional
deficiencies are uncommon in the United States and as a result,
US physicians may be unfamiliar with their clinical features.
Case 1, a 22-month-old male child, was admitted with severe kwashiorkor.
He was breastfed until 13 months of age. Because of a history
of chronic eczema and perceived milk intolerance, he was started
on a rice beverage after weaning. On average, he consumed 1.5
L of this drink daily. Intake of solid foods was very poor. As
this rice beverage, which was fallaciously referred to as rice
milk, is extremely low in protein content, the resulting daily
protein intake of 0.3 g/kg/day was only 25% of the recommended
dietary allowance. In contrast, caloric intake was 72% of the
recommended energy intake, so the dietary protein to energy ratio
was very low. A photograph of the patient after admission illustrates
the typical features of kwashiorkor: generalized edema, hyperpigmented
and hypopigmented skin lesions, abdominal distention, irritability,
and thin, sparse hair. Because of fluid retention, the weight
was on the 10th percentile and he had a rotund sugar baby appearance.
Laboratory evaluation was remarkable for a serum albumin of 1.0
g/dL (10 g/L), urea nitrogen <0.5 mg/dL (<0.2 mmol/L), and
a normocytic anemia with marked anisocytosis. Evaluation for other
causes of hypoalbuminemia was negative. Therapy for kwashiorkor
was instituted, including gradual refeeding, initially via a nasogastric
tube because of severe anorexia. Supplements of potassium, phosphorus,
multivitamins, zinc, and folic acid were provided. The patient
responded dramatically to refeeding with a rising serum albumin
and total resolution of the edema within 3 weeks. At follow-up
1 year later he continued to do well on a regular diet supplemented
with a milk-based pediatric nutritional supplement. The mortality
of kwashiorkor remains high, because of complications such as
infection (kwashiorkor impairs cellular immune defenses) and electrolyte
imbalances with ongoing diarrhea. Children in industrialized countries
have developed kwashiorkor resulting from the use of a nondairy
creamer as a milk alternative, but we were unable to find previous
reports of kwashiorkor caused by a health food milk alternative.
We suspect that cases have been overlooked. Case 2, a 17-month-old
black male, was diagnosed with rickets. He was full-term at birth
and was breastfed until 10 months of age, when he was weaned to
a soy health food beverage, which was not fortified with vitamin
D or calcium. Intake of solid foods was good, but included no
animal products. Total daily caloric intake was 114% of the recommended
dietary allowance. Dietary vitamin D intake was essentially absent
because of the lack of vitamin D-fortified milk. The patient lived
in a sunny, warm climate, but because of parental career demands,
he had limited sun exposure. His dark complexion further reduced
ultraviolet light-induced endogenous skin synthesis of vitamin
D. The patient grew and developed normally until after his 9-month
check-up, when he had an almost complete growth arrest of both
height and weight. The parents reported regression in gross motor
milestones. On admission the patient was unable to crawl or roll
over. He could maintain a sitting position precariously when so
placed. Conversely, his language, fine motor-adaptive, and personal-social
skills were well-preserved. Generalized hypotonia, weakness, and
decreased muscle bulk were present. Clinical features of rickets
present on examination included: frontal bossing, an obvious rachitic
rosary (photographed), genu varus, flaring of the wrists, and
lumbar kyphoscoliosis. The serum alkaline phosphatase was markedly
elevated (1879 U/L), phosphorus was low (1.7 mg/dL), and calcium
was low normal (8.9 mg/dL). The 25-hydroxy-vitamin D level was
low (7.7 pg/mL) and the parathyroid hormone level was markedly
elevated (114 pg/mL). The published radiographs are diagnostic
of advanced rickets, showing diffuse osteopenia, frayed metaphyses,
widened epiphyseal plates, and a pathologic fracture of the ulna.
The patient was treated with ergocalciferol and calcium supplements.
The published growth chart demonstrates the dramatic response
to therapy. Gross motor milestones were fully regained within
6 months. The prominent neuromuscular manifestations shown by
this patient serve as a reminder that rickets should be considered
in the differential diagnosis of motor delay.
Hypocalcemic tetany in 'alternative'
soy milk nutrition in the first months of life
Klin
Padiatr. 1996 Nov-Dec;208(6):323-6.
Anil M,
Demirakca S, Dotsch J, Kiess W.
Abteilung Allgemeine Padiatrie und Neonatologie, Justus Liebig
Universitat Giessen.
A 14 weeks old
infant was admitted to the intensive care unit with life-threatening
hypocalcemic-hyperphosphatemic spasms. Hypocalcemia-hyperphosphatemia
was found to have been caused by feeding a high phosphate/ low
calcium soy milk. The daily uptake of calcium was calculated to
have been 3.3-6 mmol that of phosphate 30 mmol. The parents strongly
believed that soy milk formulas were equivalent to breast milk
and cow's milk formulas and lived on a strictly vegetarian diet.
Therapy with calcium (at an initial dose of 2.25 mmol/kg/day)
and 1.25 OH vitamin D3 (Rocaltrol, 0.25 microgram/day) normalized
Ca, PO4, vitamin D and parathyroid hormone levels rapidly. Vegetarian
feeding had led to life-threatening hypocalcemic hyperphosphatemic
spasms in the infant. We conclude that malnutrition and false
nutritional beliefs have to be included as a potential cause of
early hypocalcemia in infants.
Manipulation of prenatal hormones
and dietary phytoestrogens during adulthood alter the sexually
dimorphic expression of visual spatial memory.
BMC
Neurosci. 2001;2(1):21. Epub 2001 Dec 18.
Lund TD,
Lephart ED.
The
Neuroscience Center Brigham Young University, Provo, Utah 84602,
USA.
BACKGROUND:. In
learning and memory tasks, requiring visual spatial memory (VSM),
males exhibit higher performance levels compared to females (a
difference attributed to sex steroid hormonal influences). Based
upon the results from our companion investigation, this study
examined the influence of prenatal sex steroid hormone manipulations
on VSM in adulthood, as assessed in the radial arm maze. Additionally,
the influence of dietary soy phytoestrogens (i.e., the presence
of high or low estrogen-like compounds present in the animal's
diet) on VSM was examined in combination with the prenatal hormonal
manipulations. RESULTS:. Radial arm maze performance on a phytoestrogen-rich
diet: 1) females treated prenatally with testosterone were masculinized
and acquired/performed in a manner similar to control or oil-treated
males and 2) males treated prenatally with an androgen receptor
blocker (flutamide) were feminized and acquired/performed in a
fashion typical of control or flutamide-treated females. When
a diet change was initiated in adulthood, control phytoestrogen-rich
fed females outperformed control females switched to a phytoestrogen-free
diet. Whereas, in control males the opposite diet effect was identified.
Furthermore, flutamide-treated males fed a phytoestrogen-rich
diet outperformed flutamide-treated males switched to a phytoestrogen-free
diet. CONCLUSIONS:. These results suggest that prenatal hormonal
manipulations significantly sex-reverse the normal sexually dimorphic
expression of VSM. Specifically, VSM was enhanced in females treated
with testosterone and inhibited in males treated with flutamide.
Finally, dietary soy phytoestrogens set a bias on learning and
memory in these hormonally manipulated animals in a predictable
manner and these data confirm and extend the findings in our companion
paper.
Serum plant
sterols as a potential risk factor for coronary heart disease.
Metabolism.
2002 Dec;51(12):1519-21. Sudhop
T, Gottwald BM, von Bergmann K.
Department of Clinical
Pharmacology, University of Bonn, Bonn, Germany.
In patients with the inherited
disease of phytosterolemia, elevated concentrations of plant sterols
(eg, campesterol and sitosterol) have been implicated as a risk
factor for premature atherosclerosis. Whether plasma concentrations
of campesterol and sitosterol are risk factors for coronary heart
disease (CHD) in nonphytosterolemia subjects has not been established.
Therefore, the present study examined the role of plant sterols
in patients admitted for elective artery coronary bypass graft
(ACBG). Serum concentrations of campesterol and sitosterol, as
well as lathosterol, desmosterol, cholestanol, and lipoproteins
were analyzed in 42 men and 11 women without lipid-lowering treatment
during the past. Twenty-six patients reported a positive family
history in their first-degree relatives for CHD. Lipid profile
and other risk factors were comparable in both groups. Patients
with a positive family history for CHD had significant higher
plasma levels of campesterol (.50 +/-.17 v.38 +/-.16 mg/dL; P
=.011), sitosterol (.40 +/-.11 v.31 +/-.11 mg/dL; P =.004) and
their ratios to cholesterol. Lathosterol, desmosterol, cholestanol,
and their ratios to cholesterol were not significantly different.
Analysis of covariance (ANCOVA) analysis showed no influence of
sex, age, triglycerides, total-, low-density lipoprotein (LDL)-,
and high-density lipoprotein (HDL)-cholesterol on the results,
but confirmed a strong influence of plant sterols. These
findings support the hypothesis that plant sterols might be an
additional risk factor for CHD.
Review Article: Soy infant formula and phytoestrogens
Journal of Paediatrics
and Child Health Volume 39 Issue 6 Page 401 -
August 2003 PG Tuohy
Soy infant formula
contains high levels of the isoflavones, genistein and daidzein,
which are commonly referred to as phytoestrogens. These are
non-steroidal chemicals with structural similarities to estrogen.
Infants consuming soy formula have high levels of circulating
isoflavones. These are an order of magnitude greater than the
levels of isoflavones which have been shown to produce physiological
effects in adult women consuming a high soy diet. There is
conflicting evidence about the risks and benefits of soy phytoestrogens,
with research presenting a contradictory picture. Some reviewers
suggest that early exposure to soy may prevent cancer and
heart disease. However, there is very little research on the effects
of consumption of soy phytoestrogens by human neonates. Against
this generally positive view there is an increasing number of recent
reports that suggest that in experimental animals, phytoestrogens
have adverse effects with respect to carcinogenesis, reproductive
function, immune function, and thyroid disease. Despite the absence
of adequate scientific research that quantifies the level of risk
to infants, most would argue for a precautionary approach to be
taken in situations where there are potential developmental effects
from the consumption of pharmacologically active compounds in
infancy and childhood.
Dietary genistein inactivates
rat thyroid peroxidase in vivo without an apparent hypothyroid
effect.
Toxicol
Appl Pharmacol. 2000 Nov 1;168(3):244-52.
Chang
HC, Doerge DR.
Division
of Biochemical Toxicology, Jefferson, Arkansas 72079, USA.
Biological
effects of genistein are currently under investigation by the
National Toxicology Program because of widespread and increasing
soy consumption by humans and evidence for modulation of endocrine
function. Rats were exposed to genistein aglycone in soy-free
feed fortified at 0, 5, 100, and 500 ppm starting in utero through
20 weeks. Thyroid glands and serum were analyzed for total genistein
(aglycone + conjugates) using HPLC with electrospray mass spectrometric
detection. Microsomal thyroid peroxidase (TPO) activity was measured
spectrophotometrically. The total genistein content in rat serum
was as high as 8 microM, and significant dose-dependent increases
of genistein in thyroid tissue up to 1 pmol/mg were found in male
and female rats. The activity of TPO in male and female rats was
found to be reduced by up to 80% in a dose-dependent manner. Male
and female rats consuming a standard soy-based rodent diet (NIH
31) had TPO activity approximately 50% lower than rats consuming
a soy-free diet and this loss was commensurate with measured serum
levels of isoflavones. Suicide inactivation of rat, porcine, and
human TPO was observed in vitro at concentrations of genistein
aglycone comparable to those measured in rat thyroids. Thyroid
hormone levels (T3, T4, TSH) in serum, thyroid weights, and histopathology
showed no differences between treated and untreated groups. These
findings suggest that, even though substantial amounts of TPO
activity are lost concomitant to soy isoflavone consumption by
normal rats, the remaining enzymatic activity is sufficient to
maintain thyroid homeostasis in the absence of additional perturbations.
Neonatal exposure to genistein
induces estrogen receptor (ER)alpha expression and multioocyte
follicles in the maturing mouse ovary: evidence for ERbeta-mediated
and nonestrogenic actions.
Biol
Reprod. 2002 Oct;67(4):1285-96.
Jefferson
WN, Couse JF, Padilla-Banks E, Korach KS, Newbold RR.
Developmental Endocrinology Section, Laboratory of Molecular Toxicology,
Environmental Toxicology Program, National Institute of Environmental
Health Sciences, Research Triangle Park, North Carolina 27709,
USA.
Outbred
CD-1 mice were treated neonatally on Days 1-5 with the phytoestrogen,
genistein (1, 10, or 100 micro g per pup per day), and ovaries
were collected on Days 5, 12, and 19. Ribonuclease protection
assay analysis of ovarian mRNA showed that estrogen receptor beta
(ERbeta) predominated over ERalpha in controls and increased with
age. Genistein treatment did not alter ERbeta expression, however,
ERalpha expression was higher on Days 5 and 12. ERbeta was immunolocalized
in granulosa cells, whereas ERalpha was immunolocalized in interstitial
and thecal cells. Genistein treatment caused a dramatic increase
in ERalpha in granulosa cells. Genistein-treated ERbeta knockout
mice showed a similar induction of ERalpha, which is seen in CD-1
mice, suggesting that ERbeta does not mediate this effect. Similar
ERalpha induction in granulosa cells was seen in CD-1 mice treated
with lavendustin A, a tyrosine kinase inhibitor that has no known
estrogenic actions, which suggests that this property of genistein
may be responsible. As a functional analysis, genistein-treated
mice were superovulated and the number of oocytes was counted.
A statistically significant increase in the number of ovulated
oocytes was observed with the lowest dose, whereas a decrease
was observed with the two higher doses. This increase in ovulatory
capacity with the low dose coincided with higher ERalpha expression.
Histological evaluations on Day 19 revealed a dose-related
increase in multioocyte follicles (MOFs) in genistein-treated
mice. Tyrosine kinase inhibition was apparently not responsible
for MOFs because they were not present in mice that had been treated
with lavendustin; however, ERbeta must play a role, because mice
lacking ERbeta showed no MOFs. These data taken together demonstrate
alterations in the ovary following neonatal exposure to genistein.
Given that human infants are exposed to high levels of genistein
in soy-based foods, this study indicates that the effects of such
exposure on the developing reproductive tract warrant further
investigation.
Soy formula complicates management
of congenital hypothyroidism
Archives
of Disease in Childhood 2004;89:37-40
S C Conrad,
H Chiu and B L Silverman
Department
of Pediatrics, Northwestern University Medical School, Chicago,
IL, USA
Aims:
To test the hypothesis that feeding soy formula to infants with
congenital hypothyroidism (CH) leads to prolonged increase of
thyroid stimulating hormone (TSH).
Methods:
The study was a review of 78 patients seen during their first
year of life between 1990 and 1998. Data regarding clinical diagnosis,
date of treatment initiation, TSH, levothyroxine dose, weight,
length, and diet information from each visit were collected from
the charts.
Results:
There were eight patients in the soy diet group and 70 in the
non-soy diet group. There was no significant difference between
the two groups in the starting dose of levothyroxine or the change
in this dose over one year. There was a significant difference
between the two groups in the following areas: time to TSH normalisation,
first TSH on treatment, percentage with increased TSH at 4 months
of age, percentage with increased TSH throughout the first year
of life, and in the overall trend of TSH at each visit.
Conclusions:
Infants fed soy formula had prolonged increase of TSH when
compared to infants fed non-soy formula. These infants need close
monitoring of free thyroxine and TSH measurements, and they may
need increased levothyroxine doses to achieve normal thyroid function
tests.
Physiological concentrations of dietary
genistein dose-dependently stimulate growth of estrogen-dependent
human breast cancer (MCF-7) tumors implanted in athymic nude mice.
J
Nutr. 2001 Nov;131(11):2957-62.
Ju YH,
Allred CD, Allred KF, Karko KL, Doerge DR, Helferich WG.
Department
of Food Science and Human Nutrition, University of Illinois at
Urbana-Champaign, Urbana, IL 61801, USA.
Previously our
laboratory has shown that the soy isoflavone, genistein, stimulates
growth of human breast cancer (MCF-7) cells in vivo and in vitro.
In this study, the dose-response analysis of genistein at the
physiologically achievable concentration range between 125 and
1,000 microg/g in the diet was conducted in ovariectomized athymic
nude mice implanted with MCF-7 cells. We hypothesized that genistein
at this concentration range can stimulate dose-dependently the
breast tumor growth, cell proliferation and an estrogen-responsive
pS2 gene induction. Tumor size and body weight were monitored
weekly. At completion of the study, we analyzed cellular proliferation
of tumors using incorporation of BrdU, pS2 expression of tumors
using a Northern blot analysis and total genistein level in plasma
using liquid chromatography-isotope dilution mass spectrometry
(LC-ES/MS). Dietary genistein (> or = 250 microg/g) increased
tumor size in a dose-dependent manner [8.4x the negative control
(NC) group in the 250 microg/g group, 12.0x in the 500 microg/g
group, 20.2x in the 1,000 microg/g group and 23.2x in the positive
control (PC) group]. The percentage of proliferating cells
was significantly increased by genistein at and above 250 microg/g
(5.3x the NC group in the 250 microg/g, 5.6x in the 500 microg/g,
5.0x in the 1,000 microg/g and 4.8x in the PC group). Expression
of pS2 mRNA was also significantly increased with increasing dietary
genistein levels (11.25x the NC group in the 500 microg/g
group and 15.84x in the 1,000 microg/g group). Total plasma genistein
concentrations were between 0.39 and 3.36 micromol/L in mice fed
between 125 and 1,000 microg/g genistein. In conclusion, dietary
treatment with genistein at physiological concentrations produces
blood levels of genistein sufficient to stimulate estrogenic effects,
such as breast tumor growth, cellular proliferation and pS2 expression
in athymic mice in a dose-responsive manner similar to that seen
in vitro.
Increased aggressive behavior and decreased
affiliative behavior in adult male monkeys after long-term consumption
of diets rich in soy protein and isoflavones.
Horm
Behav. 2004 Apr;45(4):278-84.
Simon
NG, Kaplan JR, Hu S, Register TC, Adams MR.
Department of Biological Sciences, Lehigh University, Bethlehem,
PA 18015, USA.
Estrogen produced by aromatization of gonadal androgen has an
important facilitative role in male-typical aggressive behavior
that is mediated through its interaction with estrogen receptors
(ER) in the brain. Isoflavones found in soybeans and soy-based
dietary supplements bind ER and have dose- and tissue-dependent
effects on estrogen-mediated responses. Yet, effects of isoflavone-rich
diets on social and aggressive behavior have not been studied.
We studied the effects of long-term (15 months) consumption of
diets rich in soy isoflavones on spontaneous social behavior among
adult male cynomolgus macaques (Macaca fascicularis) (n = 44)
living in nine stable social groups. There were three experimental
conditions which differed only by the source of dietary protein:
casein and lactalbumin (no isoflavones), soy protein isolate containing
0.94 mg isoflavones/g protein, and soy protein isolate containing
1.88 mg isoflavones/g protein. In the monkeys fed the higher
amount of isoflavones, frequencies of intense aggressive (67%
higher) and submissive (203% higher) behavior were elevated relative
to monkeys fed the control diet (P's < 0.05). In addition,
the proportion of time spent by these monkeys in physical contact
with other monkeys was reduced by 68%, time spent in proximity
to other monkeys was reduced 50%, and time spent alone was increased
30% (P's < 0.02). There were no effects of treatment on
serum testosterone or estradiol concentrations or the response
of plasma testosterone to exogenous gonadotropin-releasing hormone
(GnRH). The results indicate that long-term consumption of a diet
rich in soy isoflavones can have marked influences on patterns
of aggressive and social behavior.
beta-Sitosterol,
beta-Sitosterol Glucoside, and a Mixture of beta-Sitosterol and
beta-Sitosterol Glucoside Modulate the Growth of Estrogen-Responsive
Breast Cancer Cells In Vitro and in Ovariectomized Athymic Mice.
J
Nutr. 2004 May;134(5):1145-1151.
Ju YH,
Clausen LM, Allred KF, Almada AL, Helferich WG.
Department
of Food Science and Human Nutrition and. Department of Animal
Sciences, University of Illinois at Urbana-Champaign, Urbana,
IL 61801. Department of Physiology, University of Kentucky, Lexington,
KY 40536. IMAGINutrition and MetaResponse Science, Laguna Niguel,
CA 92677.
We hypothesized
that the phytosterols beta-sitosterol (BSS), beta-sitosterol glucoside
(BSSG), and Moducare (MC; BSS:BSSG = 99:1) could modulate the
growth of estrogen-dependent human breast cancer cells in vitro
and in vivo. The present study evaluated the estrogenic and antiestrogenic
effects of BSS, BSSG, and MC (0.001 to 150 micro mol/L) on the
proliferation of Michigan Cancer Foundation 7 (MCF-7) cells in
vitro. Both BSS (>1 micro mol/L) and MC (>50 micro mol/L)
increased MCF-7 cell proliferation. Treatment with 150 micro mol/L
of BSS and MC increased cell growth by 2.4 and 1.5 times, respectively,
compared to the negative control (NC) group. However, BSSG had
no effect at the concentrations tested. The effects of dietary
BSS, BSSG, and MC on the growth of MCF-7 cells implanted in ovariectomized
athymic mice were also evaluated. Estrogenic effects of the phytosterols
were evaluated in the NC, BSS, BSSG, and MC treatment groups,
and antiestrogenic effects were evaluated in the 17beta-estradiol
(E(2)), E(2) + BSS, E(2) + BSSG, and E(2) + MC treatment groups.
Mice were treated with dietary BSS (9.8 g/kg AIN93G diet), BSSG
(0.2 g/kg diet), or MC (10.0 g/kg diet) for 11 wk. Dietary BSS,
BSSG, and MC did not stimulate MCF-7 tumor growth. However, dietary
BSS, BSSG, and MC reduced E(2)-induced MCF-7 tumor growth by 38.9%
(P < 0.05), 31.6% (P = 0.08), and 42.13% (P < 0.05), respectively.
The dietary phytosterols lowered serum E(2) levels by 35.1, 30.2,
and 36.5% in the E(2) + BSS, E(2) + BSSG, and E(2) + MC groups,
respectively (P < 0.05), compared to that of the E(2) treatment
group. Estrogen-responsive pS2 mRNA expression in tumors did not
differ among groups, but expression of the antiapoptotic marker
B-cell lymphoma/leukemia-2 (bcl-2) in tumors from the E(2) + MC
group was downregulated, compared to that of the E(2) treatment
group. In summary, BSS and MC stimulated MCF-7 cell growth in
vitro. Although BSSG comprises only 1% of MC, BSSG made MC less
estrogenic than BSS alone in vitro. However, dietary BSS and MC
protected against E(2)-stimulated MCF-7 tumor growth and lowered
circulating E(2) levels.
Paediatric group position
statement on the use of soya protein for infants.
J
Fam Health Care. 2003;13(4):93
The British
Dietetic Association.
Breast feeding
should be strongly encouraged as providing the safest, most nutritionally
adequate form of feeding for most infants. Dietitians should discourage
the use of soya protein in children with atopy or cow's milk allergy
in the first six months of life to avoid sensitisation to soya
protein and exposure to phytoestrogens while organ systems remain
at their most vulnerable. This would include soy infant formula
and soya products such as desserts etc. When a soy-based infant
formula is used, parents should be informed of current findings
relating to phytoestrogens and health and on the clinical need
for soy formula. Any parent choosing to refuse soya for their
infant should be supported in their decision. More research into
the long-term effects of phytoestrogen exposure in infants is
needed and into whether any adverse effects are dose related.
This position statement will be updated as further evidence becomes
available.
New guidelines on infant feeding in the first
12 months of life.
J
Fam Health Care. 2003;13(4):89-90.
More J.
Royal
London Hospital, London.
Paediatric
dietitian Judy More discusses several recent directives and guidelines
on infant feeding in the first year of life. These include recommendations
that babies should be fed exclusively on breast milk for their
first six months and that soy formulae should normally be avoided
for babies under six months old. There is also specific new advice
on restricting salt intake for infants.
Adrenocortical effects of oral estrogens
and soy isoflavones in female monkeys.
J
Clin Endocrinol Metab. 2004 May;89(5):2319-25.
Wood CE,
Cline JM, Anthony MS, Register TC, Kaplan JR.
Comparative
Medicine Clinical Research Center, Wake Forest University School
of Medicine, Winston-Salem, North Carolina 27157-1040, USA.
The goal of this
study was to evaluate the long-term adrenocortical effects of
premenopausal oral contraceptives (OC) and postmenopausal conjugated
equine estrogens (CEE) and soy isoflavones in a female cynomolgus
monkey model. Half of the animals received a triphasic OC for
a period of 26 months, after which all monkeys were ovariectomized
and randomized to one of three diet groups for 36 months: 1).
isoflavone-depleted soy protein (control) (n = 54); 2). soy protein
with isoflavones (129 mg/d equivalent) (SPI+) (n = 56); or 3).
isoflavone-depleted soy protein with CEE (0.625 mg/d equivalent)
(n = 59). In the premenopausal phase, OC treatment resulted in
significantly higher cortisol (F) and lower dehydroepiandrosterone
sulfate, androstenedione, and testosterone relative to intact
controls. In the postmenopausal phase, CEE treatment resulted
in significantly higher basal F and lower dehydroepiandrosterone
sulfate, androstenedione, and testosterone when compared with
control and SPI+ diets. Serum F and androgens in the SPI+ group
did not differ significantly from the control group. The SPI+
group had significantly lower adrenal weight than either control
or CEE groups, and this effect was localized primarily to the
zona fasciculata region of the adrenal cortex. These findings
suggest that long-term estrogen treatment may contribute to an
androgen-deficient and hypercortisolemic state.
Endometrial effects of long-term treatment
with phytoestrogens: a randomized, double-blind, placebo-controlled
study.
Fertil
Steril. 2004 Jul;82(1):145-8.
Unfer
V, Casini ML, Costabile L, Mignosa M, Gerli S, Di Renzo GC.
A.G.UN.CO.,
Obstetrics and Gynecology Centre, Rome, Italy.
OBJECTIVE:
To determine the effects of 5 years of treatment with soy phytoestrogens
on histological characteristics of endometrium in postmenopausal
women. DESIGN: Randomized, double-blind, placebo-controlled study.
SETTING: Centre of Perinatal and Reproductive Medicine, Department
of Gynecological, Obstetrical, and Pediatric Sciences, University
of Perugia, Italy. PATIENT(S): Three hundred seventy-six postmenopausal
healthy women, all with intact uterus. INTERVENTION(S): Women
were distributed in two different groups using randomized criteria:
group A (n = 179) patients received soy tablets (150 mg of isoflavones
per day) for 5 years; group B (n = 197) patients received identical
appearing placebo tablets for 5 years. MAIN OUTCOME MEASURE(S):
Results of endometrial histology from biopsies obtained at baseline,
30 months, and 5 years after the beginning of the treatment. RESULT(S):
Two hundred ninety-eight women completed the 5-year treatment.
No cases of malignancy were detected during biopsy. Seventy percent
of women undergoing treatment with soy phytoestrogens had an endometrium
classified as atrophic or nonassessable versus 81% receiving placebo.
The occurrence of endometrial hyperplasia was significantly higher
in group A (3.37% vs. 0%). CONCLUSION(S): Long-term treatment
(up to 5 years) with soy phytoestrogens was associated with an
increased occurrence of endometrial hyperplasia. These findings
call into question the long-term safety of phytoestrogens with
regard to the endometrium.
More Here
Effect of soy protein containing
isoflavones on cognitive function, bone mineral density, and plasma
lipids in postmenopausal women: a randomized controlled trial.
JAMA.
2004 Jul 7;292(1):65-74.
Kreijkamp-Kaspers
S, Kok L, Grobbee DE, de Haan EH, Aleman A, Lampe JW, van der
Schouw YT.
The
Julius Center for Health Sciences and Primary Care, University
Medical Center Utrecht, The Netherlands.
CONTEXT:
Postmenopausal estrogen therapy has been posited to have some
beneficial effects on aging processes, but its use has risks.
Isoflavones, estrogenlike compounds naturally occurring in plant
foods, might confer positive effects with fewer adverse effects.
OBJECTIVE: To investigate whether soy protein with isoflavones
improves cognitive function, bone mineral density, and plasma
lipids in postmenopausal women. DESIGN, SETTING, AND PARTICIPANTS:
Double-blind, randomized, placebo-controlled trial of 202 healthy
postmenopausal women aged 60 to 75 years, recruited from a population-based
sample in the Netherlands, conducted between April 2000 and September
2001. INTERVENTION: Participants were randomly assigned to receive
25.6 g of soy protein containing 99 mg of isoflavones (52 mg genistein,
41 mg daidzein, and 6 mg glycetein or total milk protein as a
powder on a daily basis for 12 months. MAIN OUTCOME MEASURES:
Cognitive function was assessed using the following instruments:
dementia, Mini-Mental State Examination; memory, Rey Auditory
Verbal Learning Test, immediate recall, delayed recall, and recognition,
the Digit Span forward and reversed, and the Doors test; complex
attention tasks, Digit Symbol Substitution and Trailmaking, A1,
A2, and B; and verbal skills, Verbal Fluency A and N, animals
and occupations, and the Boston Naming Task. Bone mineral density
of the hip and lumbar spine was assessed using dual-energy x-ray
absorptiometry scanning. Lipid assessment included lipoprotein(a),
total cholesterol, low-density lipoprotein, high-density lipoprotein,
and triglycerides. RESULTS: A total of 175 women completed the
baseline and at least 1 postintervention analysis and were included
in the modified intent-to-treat analysis. Adherence was good (median
plasma genistein levels, 17.2 and 615.1 nmol/L for placebo and
soy group, respectively). Cognitive function, bone mineral density,
or plasma lipids did not differ significantly between the groups
after a year. CONCLUSION: This double-blind randomized trial
does not support the hypothesis that the use of soy protein supplement
containing isoflavones improves cognitive function, bone mineral
density, or plasma lipids in healthy postmenopausal women when
started at the age of 60 years or later.
Evidence for genistein mediated
cytotoxicity and apoptosis in rat brain.
Life
Sci. 2004 Jun 11;75(4):499-509.
Choi EJ,
Lee BH.
Medicinal
Science Division, Korea Research Institute of Chemical Technology,
#100, Jang-dong, Yusong, Taejon 305-343, South Korea.
The
effects of chronic treatment with high doses of genistein, a major
isoflavone of soybeans and soy-based products, have yet to be
determined and what is known remains controversial. The present
study was undertaken to investigate the cytotoxic effects of chronic
ingestion of genistein on rat brain in vivo and the observations
were compared with results from in vitro studies with primary
cultures of cortical neurons. Sprague-Dawley rats were given 2
or 20 mg/day genistein (p.o.) for four weeks. The high dose
of genistein (20 mg/day) significantly increased lactate dehydrogenase
(LDH) in rat brain tissue homogenates, whereas the low dose of
genistein (2 mg/day) decreased LDH. In addition, DNA fragmentation
was detected in homogenates of brain tissue from rats receiving
either dose of genistein. These results are consistent with those
of in vitro studies indicating that high concentrations of genistein
caused cytotoxicity and DNA ladder formation in primary cultures
of cortical neurons. Genistein decreased the expression of
the 32 kDa caspase-3 precursor and increased the levels of cleaved
caspase-3 (18 kDa) in both rat brain tissue homogenates and in
primary cultures of cortical neurons. Furthermore, expression
of poly (ADP-ribose) polymerase (PARP) was also decreased in both
experimental systems. These results suggest that chronic administration
of genistein at high doses may induce cytotoxicity and apoptosis
in the rat brain.
The effect of soy protein isolate
on bone metabolism.
Menopause.
2004 May-Jun;11(3):290-8.
Gallagher
JC, Satpathy R, Rafferty K, Haynatzka V.
Bone
Metabolism Unit, School of Medicine and the Osteoporosis Research
Center, Creighton University, Omaha, NE, USA.
OBJECTIVE: This
double-blind, 15-month pilot study was designed to investigate
the effect of soy protein isolate with varying concentrations
of isoflavones on early postmenopausal bone loss and lipids. DESIGN:
A total of 65 women, with a mean age of 55 years and 7.5 years
since menopause, were randomized to one of three groups; soy protein
with 96 mg isoflavones/day, soy with 52 mg isoflavones/day, or
soy without isoflavones (< 4 mg isoflavones/day). Soy was given
for 9 months and then discontinued; participants were followed
for an additional 6 months. Bone mineral density (BMD) and blood
lipids were measured during this time. RESULTS: Measurement of
serum isoflavones at 3 months showed dose-related increases in
the three groups. There was no significant effect of the soy supplements
on BMD of the spine or femoral neck in any of the three groups.
BMD increased significantly in the trochanter at 9 months (P =
0.0219) and at 15 months (P < 0.05) in the group given isoflavone-free
soy compared with the other two groups. There was no significant
effect of soy on lipid metabolism at the end of the intervention.
CONCLUSION: The present study did not find a significant positive
effect of soy protein isolate supplemented with isoflavones on
BMD and the serum lipid profile in early postmenopausal women.
Genistein at a concentration
present in soy infant formula inhibits Caco-2BBe cell proliferation
by causing G2/M cell cycle arrest.
J
Nutr. 2004 Jun;134(6):1303-8.
Chen AC,
Donovan SM.
Division
of Nutritional Sciences, University of Illinois at Urbana-Champaign,
Urbana, IL 61801, USA.
Fifteen percent
of all U.S. infants are fed soy formulas containing up to 47 mg/L
of isoflavones (>65% as genistin + genistein); thus, these
infants' intestines are exposed to a high dose of genistein, a
phytoestrogen and tyrosine kinase inhibitor. Little attention
has been focused on genistein's impact on the developing intestine.
We hypothesized that a high dose of genistein would inhibit intestinal
cell growth. Caco-2BBe human intestinal cells were exposed to
0, 3.7, and 111 micro mol/L (0, 1, and 30 mg/L) genistein in DMEM
+ 0.5% fetal bovine serum for 24-48 h. Cell number, thymidine
incorporation, apoptosis, and cell cycle analyses were performed.
The low genistein concentration increased intestinal cell proliferation
by 28% (P = 0.001), but did not affect cell number or caspase-3
activity compared to the control. Furthermore, the addition of
ICI, an estrogen receptor antagonist, negated the proliferative
effect of the low genistein. In contrast, the high genistein concentration
reduced cell number by 40%, proliferation by 94%, and caspase-3
activity by 50% compared to the control (P < 0.05). Cell cycle
analysis after 48 h exposure to high genistein revealed 37% of
cells in G0/G1 and 35% in G2/M vs. 71% in G0/G1 and 17% in G2/M
for the control and low genistein groups. Thus, a biphasic
effect of genistein was seen with a low dose stimulating intestinal
cell proliferation through the estrogen receptor, whereas a high
dose of genistein inhibited intestinal cell proliferation and
altered cell cycle dynamics. A high dose of genistein may potentially
compromise intestinal growth.
Bioavailability of zinc in milk
and soy protein-based infant formulas.
J
Nutr. 1976 Jul;106(7):913-7.
Momcilovic
B, Belonje B, Giroux A, Shah BG.
Total
femur zinc of young rats was used to evaluate the biological availability
of zinc in milk and soy protein-based infant formulas. A zinc
deficient diet (0.8 mug Zn/g) containing egg white protein was
supplemented with graded levels of zinc from zinc sulfate, milk
and soy protein-based infant formulas. A plot of total femur zinc
(log) after feeding the diet for 3 weeks versus the zinc added
to the diet gave a linear relationship over the range of 0, 3,
6, 9 and 12 mug/g added zinc. By using a slope-ratio bioassay
model, the relative biological availability of endogenous and
added zinc in milk-based formula was estimated to be 0.86 and
that of soy-based formula 0.67 (zinc sulphate = 1.00) with corresponding
95% fiducial limits being 0.82 to 0.91 and 0.62 to 0.71. Thus,
to provide equivalent amounts of available zinc, the total zinc
content of the soy protein-based formula would need to be at least
20% higher than that of the formula containing milk protein.
Genotoxicity of the isoflavones
genistein, daidzein and equol in V79 cells.
Toxicol
Lett. 2004 Jun 15;151(1):151-62.
Di Virgilio
AL, Iwami K, Watjen W, Kahl R, Degen GH.
Institut
fur Arbeitsphysiologie an der Universitat Dortmund, Ardeystr,
67, D-44139 Dortmund, Germany.
Hormonally
active chemicals in the human diet, such as man-made estrogenic
chemicals or plant-derived compounds (phytoestrogens), have become
a matter of public concern. A significant part of human exposure
to phytoestrogens is attributable to soy isoflavones. Besides
their estrogenic properties, soy isoflavones also exert genotoxic
actions. In this paper, the micronucleus (MN) assay in V79 cells
was used to study chromosomal genotoxicity. Genistein caused a
clear dose-related induction of MN within the range of 5-25 microM;
MN rates were declining at higher genistein concentrations. This
was probably due to cytotoxicity of genistein since reduced neutral
red uptake and MTT formation with an IC(50) of about 75 microM
occurred. Daidzein induced a comparatively shallow increase in
the number of MN between 25 and 100 microM. In contrast, the daidzein
metabolite equol caused an increase in the number of MN up to
25 microM with no further increase at higher concentrations. Additional
staining with anti-kinetochore (CREST) antibodies served to determine
if the micronuclei contain whole chromosomes or acentric fragments.
Genistein induced mostly CREST(-) micronuclei, i.e. MN with chromosomal
fragments, thus indicative of a clastogenic mode of action. MN
induced by high concentrations of daidzein were partly CREST(+)
and CREST(-), whilst equol induced mostly CREST(+) micronuclei
indicative of an aneugenic action. These results point to a differential
genotoxicity of phytoestrogens.
Dietary soy and increased risk of bladder
cancer: A prospective cohort study of men in Shanghai, China.
Int
J Cancer. 2004 Nov 1;112(2):319-23.
Sun CL,
Yuan JM, Wang XL, Gao YT, Ross RK, Yu MC.
USC/Norris
Comprehensive Cancer Center, University of Southern California
Keck School of Medicine, Los Angeles, CA, USA.
To
verify our previous finding of a positive association between
dietary soy and bladder cancer risk, we examined the association
in a second, geographically distinct prospective cohort of Chinese
subjects, the Shanghai Cohort Study. Briefly, 18,244 men aged
45-64 years were recruited between January 1986 and September
1989. As of December 31, 2002, 61 incident bladder cancer cases
were identified. Information on soy consumption was obtained through
in-person interviews at baseline using a food frequency questionnaire.
Cox proportional hazard regression methods were used to estimate
relative risks (RR) and their corresponding 95% confidence intervals
(CI), with adjustment for age (years) at baseline interview, level
of education and other potential confounders. Compared to men
consuming soy less than once a week, the RR (95% CI) for those
who consumed soy 1-<3 times per week, 3-<7 times a week
and daily were 2.05 (0.80-5.29), 2.45 (0.89-6.76) and 4.61 (1.57-13.51),
respectively (p for trend = 0.004), after adjustment for age,
cigarette smoking and level of education. The soy-bladder
cancer risk associations in smokers and non-smokers were comparable.
The soy-bladder cancer relationship became stronger when the analysis
was restricted to subjects with 2 or more years of follow-up.
Effects of Soy-Derived Isoflavones
and a High-Fat Diet on Spontaneous Mammary Tumor Development in
Tg.NK (MMTV/c-neu) Mice.
Nutr
Cancer. 2004;50(1):46-54.
Luijten
M, Thomsen AR, van den Berg JA, Wester PW, Verhoef A, Nagelkerke
NJ, Adlercreutz H, van Kranen HJ, Piersma AH, Sorensen IK, Rao
GN, van Kreijl CF.
Phytoestrogens
such as isoflavonoids and lignans have been postulated as breast
cancer protective constituents in soy and whole-grain cereals.
We investigated the ability of isoflavones (IFs) and flaxseed
to modulate spontaneous mammary tumor development in female heterozygous
Tg.NK (MMTV/c-neu) mice. Two different exposure protocols were
applied, either from 4 wk of age onward (postweaning) or during
gestation and lactation (perinatal). In the postweaning exposure
study, mice were fed IFs or flaxseed in a high-fat diet. In addition,
flaxseed in a low-fat diet was tested. Postweaning exposure to
IFs and flaxseed tended to accelerate the onset of mammary adenocarcinoma
development, although tumor burden at necropsy was not changed
significantly. Perinatal IF exposure resulted in enhanced mammary
gland differentiation, but palpable mammary tumor onset was not
affected. However, tumor burden at necropsy in the perinatal exposure
study was significantly increased in the medium- and high-IF dose
groups. Comparison of both exposure scenarios revealed a strongly
accelerated onset of tumor growth after perinatal high-fat diet
exposure compared with the low-fat diet. This study shows that
breast cancer-modulating effects of phytoestrogens are dependent
both on the background diet and on the timing of exposure in the
life cycle.
Mammary gland morphology in Sprague-Dawley
rats following treatment with an organochlorine mixture in utero
and neonatal genistein.
Toxicol
Sci. 2004 Jan;77(1):91-100
Foster
WG, Younglai EV, Boutross-Tadross O, Hughes CL, Wade MG.
Department
of Obstetrics and Gynecology, McMaster University and Health Sciences
Centre, Hamilton, Ontario, Canada.
In a related reproductive
toxicology study designed to investigate the effects of in utero
exposure to environmental toxicants and potential interaction
with postnatal genistein, gross enlargement of thoracic mammary
glands was observed in female offspring at 200 days of age. Therefore,
the objective of this study was to analyze the effect of in utero
exposure to a mixture of toxicants on mammary gland morphology.
Time-mated Sprague-Dawley rats were treated on days 9-16 of gestation
with vehicle or a mixture of environmental toxicants at 1x the
acceptable daily intake. Furthermore, it is unclear whether postnatal
exposure to phytoestrogens in soy formulas poses breast cancer
benefit or risk, and potential interactions with environmental
toxicants are unknown. Therefore, half the female pups from each
treatment group received either subcutaneous vehicle or genistein
(10 microg/g body weight [bw]/day) on postnatal days 2-8. Following
necropsy at 200 days of age, a pathologist, blinded to treatment
groups, examined mammary gland histopathology. Only mild histological
changes were found in mammary glands of rats exposed to the mixture
in utero while pronounced ductal hyperplasia, lactational changes,
and fibrosis were observed in mammary glands from the genistein
group and were more prominent in the mixture + genistein group.
Mammary glands of the control group were histologically normal.
Collectively, our results reveal that postnatal exposure to
pharmacological levels of genistein induces profound morphological
changes in the mammary glands of adult female rats, and that high
levels of phytoestrogens possess the potential to modulate the
toxicological effects of toxicant mixtures.
Dietary soy protein and isoflavones
have no significant effect on bone and a potentially negative
effect on the uterus of sexually mature intact Sprague-Dawley
female rats.
Menopause.
2005 May-Jun;12(3):291-8.
Nakai
M, Cook, L, Pyter, LM, Black M, Sibona, J, Turner RT, Jeffery
EH, Bahr JM.
Departments
of Animal Sciences, University of Illinois, Urbana, IL, USA.
OBJECTIVE:
To evaluate the effect of dietary soy protein and isoflavones
on bone and the reproductive tract in premenopausal rats. DESIGN:
Three-month-old intact Sprague-Dawley female rats (N = 50) were
fed diets containing casein, soy protein, or casein with isoflavone
extract for 12 weeks. The amount of casein, soy protein, and extract
(per kilogram diet) in each group was: (1) 200 g casein (control);
(2) 100 g casein plus 100 g soy protein (low soy); (3) 200 g soy
protein (high soy); 4) 200 g casein plus 17.2g extract (low extract);
and (5) 200 g casein plus 34.4 g extract (high extract). Diet
consumption, body weight, uterine wet weight, urinary deoxypyridinoline
concentration, and bone mineral density of the femur and lumbar
vertebrae were measured. Femur rigidity was evaluated by histomorphometry.
The uterus and vagina were studied histologically. RESULTS: Rats
in all treatment groups had lower body weights and lower deoxypyridinoline
concentrations compared with controls, but none of the differences
was statistically significant. There was no significant difference
in femur and lumbar bone mineral density, uterine wet weights,
or histomorphometry between the control and treatment groups.
Histologically, uteri and vaginae were normal in all groups
except that 1 of 10 rats in the high-soy group and 2 of 10 rats
in the high-extract group showed extensive squamous metaplasia
in the uterine gland. CONCLUSION: These results suggest that dietary
isolated soy protein and isoflavones have no effect on bone and
the vagina during premenopausal period, but may have an adverse
effect on the uterus.
Pet
Abstracts
Effect of dietary soy on serum thyroid
hormone concentrations in healthy adult cats.
Am
J Vet Res. 2004 May;65(5):586-91
White
HL, Freeman LM, Mahony O, Graham PA, Hao Q, Court MH.
Department
of Clinical Sciences, School of Veterinary Medicine, Tufts University,
North Grafton, MA 01536, USA.
OBJECTIVE:
To compare effects of short-term administration of a soy diet
with those of a soy-free diet on serum thyroid hormone concentrations
in healthy adult cats. ANIMALS: 18 healthy adult cats. PROCEDURE:
Cats were randomly assigned to receive either a soy or soy-free
diet for 3 months each in a crossover design. Assays included
CBC, serum biochemical profile, thyroid hormone analysis, and
measurement of urinary isoflavone concentrations. RESULTS: Genistein,
a major soy isoflavone, was identified in the urine of 10 of 18
cats prior to dietary intervention. Compared with the soy-free
diet, cats that received the soy diet had significantly higher
total thyroxine (T4) and free T4 (fT4) concentrations, but unchanged
total triiodothyronine (T3) concentrations. The T3/fT4 ratio was
also significantly lower in cats that received the soy diet. Although
the magnitudes of the increases were small (8% for T4 and 14%
for fT4), these changes resulted in an increased proportion of
cats (from 1/18 to 4/18) that had fT4 values greater than the
upper limit of the laboratory reference range. There was no significant
effect of diet on any other measured parameter. CONCLUSIONS AND
CLINICAL RELEVANCE: Short-term administration of dietary soy
has a measurable although modest effect on thyroid hormone homeostasis
in cats. Increase in T4 concentration relative to T3 concentration
may result from inhibition of 5'-iodothyronine deiodinase or enhanced
T3 clearance. Soy is a common dietary component that increases
serum T4 concentration in cats
Induction of micronuclei,
DNA strand breaks and HPRT mutations in cultured Chinese hamster
V79 cells by the phytoestrogen coumoestrol.
Food
Chem Toxicol. 1997 Jun;35(6):605-13.
Kulling
SE, Metzler M.
Institute
of Food Chemistry, University of Karlsruhe, Germany.
Coumoestrol
(COUM), genistein (GEN) and daidzein (DAI) are major phytoestrogens
present in numerous plants eaten by humans and food-producing
animals. Little is known about the genotoxicity of these natural
compounds. The effects of COUM, GEN and DAI were studied in
cultured Chinese hamster V79 cells at various endpoints. None
of the substances affected the cytoplasmic microtubule complex
or the mitotic spindle. However, COUM and GEN but not DAI proved
to be strong inducers of DNA strand breaks and micronuclei containing
acentric fragments, as shown with antikinetochore antibodies.
The clastogenicity of GEN may be due to its non-intercalative
inhibitory effect on topoisomerase II, whereas COUM may act through
topoisomerase II inhibition and/or DNA intercalation. COUM was
also a clear inducer of hypoxanthine guanine phosphoribosyltransferase
(HPRT) mutations in V79 cells; GEN was only marginally active
and DAI inactive at this endpoint. This is the first report on
the clastogenicity and mutagenicity of COUM in mammalian cells.
Phytoestrogens: adverse effects
on reproduction in California quail.
Science.
1976 Jan 9;191(4222):98-100.
Leopold
AS, Erwin M, Oh J, Browning B.
Phytoestrogens,
largely formononetin and genistein, are produced in the leaves
of stunted desert annuals in a dry year. When ingested by California
quail, these compounds apparently inhibit reproduction and prevent
the production of young that will not have adequate food. In a
wet year, forbs grow vigorously and phytoestrogenic substances
are largely absent. Quail then breed prolifically and the abundant
seed crop carries the enlarged population through the winter.
Evaluation of environmental, nutritional,
and host factors in cats with hyperthyroidism.
J
Vet Intern Med 1999 Jul-Aug;13(4):323-9
Kass PH,
Peterson ME, Levy J, James K, Becker DV, Cowgill LD.
Department
of Population Health and Reproduction, School of Veterinary Medicine,
University of California, Davis 95616-8746, USA. phkass@ucdavis.edu
The
pathologic changes associated with hyperthyroidism (adenomatous
hyperplasia, adenoma of the thyroid gland) have been well characterized
in cats, but the pathogenesis of these changes remains unclear.
In this research, we undertook a case-control study to search
for potential risk factors for this disease. Owners of 379 hyperthyroid
and 351 control cats were questioned about their cats' exposure
to potential risk factors including breed, demographic factors,
medical history, indoor environment, chemicals applied to the
cat and environment, and diet. The association between these hypothesized
risk factors and outcome of disease was evaluated by conditional
logistic regression. Two genetically related cat breeds (ie, Siamese
and Himalayan) were found to have diminished risk of developing
hyperthyroidism. Cats that used litter had higher risk of developing
hyperthyroidism than those that did not. Use of topical ectoparasite
preparations was associated with increased risk of developing
hyperthyroidism. Compared with cats that did not eat canned
food, those that ate commercially prepared canned food had an
approximate 2-fold increase in risk of disease. When these
4 variables (breed, use of cat litter, consumption of canned cat
food, and use of topical ectoparasite preparations) from the univariate
analysis were selected for further study as candidate risk factors
and analyzed by multivariate conditional logistic regression,
a persistent protective effect of breed (ie, Siamese or Himalayan)
was found. In addition, results suggested a 2- to 3-fold increase
in risk of developing hyperthyroidism among cats eating a diet
composed mostly of canned cat food and a 3-fold increase in risk
among those using cat litter. In contrast, the use of commercial
flea products did not retain a strong association. The results
of this study indicate that further research into dietary and
other potentially important environmental factors (eg, cat litter)
is warranted.
Identification of phytoestrogens
in the urine of male dogs.
J
Steroid Biochem 1988 Dec;31(6):987-94
Juniewicz
PE, Pallante Morell S, Moser A, Ewing LL.
Department
of Population Dynamics, Johns Hopkins School of Hygiene and Public
Health, Baltimore, MD 21205.
It
is becoming increasingly apparent that dietary factors may play
a role in the etiology of hormone dependent neoplasias. It has
been hypothesized that estrogens play some role in the etiology
of benign prostatic hyperplasia (BPH) in the canine. The presence
of estrogen receptor binding activity in a fraction of canine
urine purified by high performance liquid chromatography (HPLC)
that did not correspond to estriol, estradiol, estrone or any
of their primary metabolites was observed in the present study.
We used thermospray-mass spectrometry and GC-MS to identify
the phytoestrogens daidzein, equol, formononetin and genistein
in HPLC purified fractions of urine obtained from male beagles.
Using the same techniques we also confirmed the presence of daidzein
and genistein in the commercial diet fed to these same dogs.
Using the immature rat uterine cytosol estrogen receptor assay,
relative binding affinities of 0.08, 1.1, less than 0.01 and 3.9%
were obtained for daidzein, equol, formononetin and genistein,
respectively when compared to estradiol (100%). In conclusion,
phytoestrogens are present in urine of male beagles. Moreover,
the commercial diet fed to these dogs contains isoflavones which
can be converted to equol by intestinal microflora. These
results suggest the need for investigations of phytoestrogens
(e.g. equol) excreted into the urine daily and its relationship
to the incidence and severity of BPH in the dog.
Identification and concentration
of soy isoflavones in commercial cat foods.
Am
J Vet Res 2002 Feb;63(2):181-5
Court
MH, Freeman LM.
Department
of Pharmacology and Experimental Therapeutics, School of Medicine,
Tufts University, Boston, MA 02111, USA.
OBJECTIVE:
To determine the absolute and relative soy isoflavone content
in commercial cat foods. SAMPLE POPULATION: 14 dry, 6 semimoist,
and 22 moist commercial cat foods. PROCEDURE: Soy isoflavone content
of each food was determined by use of acid-methanol hydrolysis
and high-pressure liquid chromatography with ultraviolet absorbance
detection. Isoflavones were identified and quantified by reference
to authentic standards. RESULTS: Genistein and daidzein were the
major soy isoflavones identified in 24 of 42 foods, with concentrations
ranging from 1 to 163 microg/g of food. Foods labeled as containing
soybean solids (16/42) had isoflavone concentrations > 11 microg/g.
More dry (13/14) and semimoist (6/6) foods contained isoflavones
than moist foods (5/22). Isoflavone content and food cost were
negatively correlated for dry and semimoist foods but not for
moist foods. Total amount of isoflavone consumed by cats fed these
soy-containing foods as a sole maintenance diet was estimated
to be between 0.6 and 4.5 mg/kg of body weight/d, which is comparable
to concentrations in humans that result in a measurable although
modest effect on serum concentrations of steroid and thyroid hormones.
CONCLUSIONS AND CLINICAL RELEVANCE: Genistein and daidzein
are common constituents of commercial cat foods. Predictors of
isoflavone content included ingredient labeling, food type, and
food cost. Soy isoflavones in some commercial cat foods were detected
in amounts predicted to have a biological effect.
Effects of the protein phosphorylation
inhibitor genistein on maturation of pig oocytes in vitro.
J
Reprod Fertil 1993 Jul;98(2):529-35
Jung T,
Fulka J Jr, Lee C, Moor RM.
Department
of Molecular Embryology, Institute of Animal Physiology and Genetics
Research, Babraham, Cambridge, UK.
In
vitro maturation of cumulus enclosed and denuded pig oocytes was
reversibly inhibited by the protein kinase inhibitor genistein.
The half-maximal effect on maturation was observed at 40 micrograms
ml-1. Genistein inhibited total protein phosphorylation and synthesis
with the same dose-response relationship (ED50: 40 micrograms
ml-1). Protein phosphorylation and synthesis patterns were changed
by effective concentrations of genistein. Pig oocytes were sensitive
to genistein during the first 12 h of in vitro maturation. This
genistein sensitive period corresponds closely with the period
of sensitivity to the protein synthesis inhibitor cycloheximide.
Whereas the inhibition of protein synthesis affects only nuclear
membrane breakdown and not chromatin condensation, genistein inhibits
both events. The results of these experiments suggest that protein
phosphorylation and synthesis play major roles during pig oocyte
maturation in vitro. It is concluded that genistein inhibited
protein phosphorylation is a regulator of chromatin condensation,
whereas both new protein synthesis and phosphorylation appear
to be required for nuclear membrane disassembly. Caution about
this second conclusion is, however, necessary because of the dual
action of genistein on both protein phosphorylation and indirectly
on protein synthesis.
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