From Pink Pills to Phytoestrogens — spot the difference
Women
who are wary of hormone replacement therapy are being turned on to
‘natural’ preparations believing that they are safe and
effective. Camille Guy fears they are being sold a pup.
Womens
Health Watch September/October 1998.
At the turn
of the century Dr Williams Pink Pills for Pale People, three shillings
a box, were touted as relieving menstrual problems. Analysed, they
turned out to contain one tenth of a penny’s worth of nothing
very much, coated in starch and sugar.
Middle-aged
women eyeing today’s over-the-counter remedies might wonder
whether they are being offered Pink Pills – or more potent
nostrums. Two Auckland scientists warn that products like Red Clover
Pills (and equivalent pills targeted at men with prostate problems) are
not only outrageously priced, but possibly harmful. One health product
manufacturer says he is ‘seriously worried’ about these
profitable plant or phytoestrogen pills (his estimate of the cost of
$30 month’s supply is a couple of dollars). Auckland
environmental consultant and phytoestrogen researcher Dr Mike
Fitzpatrick is concerned too. The phytoestrogens in red clover disrupt
the endocrine system and suppress thyroid hormone synthesis, he says,
as well as causing genetic damage to cells. They are also potential
carcinogens.
But there
is big money to be made in the hormone replacement therapy market, and
natural HRT is the latest craze, he says.
‘But
where is the research to back up the health claims and where are the
guarantees of consumer safety? They have done less research than they
would on cats and dogs if this were a veterinary medicine. If the New
Zealand government is willing to let manufacturers of phytoestrogen
products make medicinal claims, then those claims should at least be
backed with the kind of research I hope goes into medicinals.’
But they
don’t have to be. Because phytoestrogen ‘dietary
supplements’ are classified as foods, not drugs, they are
virtually unregulated. They can be sold that way so long as no
therapeutic claims are made. Even when claims are made (in press and
television advertising), the Ministry of Health seems reluctant to
clamp down.
The labels
on phytoestrogen supplements may bear coy messages like
‘considered valuable in balancing female hormone levels’,
but other promotional material is more explicit. Often the pitch is
that phytoestrogen pills are hormone replacement therapy substitutes
– only natural and better. In case you don’t get the
message, the products are called HRT – standing for Herbal
Replacement Tablets – described as made from extracted plant
substances that ‘work in harmony with the body’, that just
nudge natural processes along.
Blackmores
have sent out a laminated ‘clinical guide’ to GPs,
suggesting that the possible clinical applications for their products
include hyperlipidaemia and heart disease, cancer prevention,
menopause, osteoporosis and renal disease and offering the reassurance
that ‘there has been no evidence of human toxicity from
individual isoflavones in the doses thus far used in human
trials.’
The claim
of safety is carefully phrased – and with good reason. Red clover
pills are, after all, made from a variety of clover that continues to
render grazing sheep infertile, less sexually receptive and more
aggressive. Clover estrogens (and soy estrogens when sheep forage on
that plant) can cause ovarian cysts and irreversible endometriosis in
ewes, and blocked urethra, enlarged teats and lactation in wethers
(castrated rams).
First
alerted to the sheep problems in Australia in the 1940s, scientists
came to understand that phytoestrogens serve as a plant’s natural
defence against grazing animals. When plants like red clover are
stressed (by drought, or even by spraying with herbicide) higher levels
of estrogens are produced. By mimicking mammalian estrogens, plant
estrogens diminish the fertility of predators and so protect the
plants.
Phytoestrogens
in clover were a curse for sheep farmers. The implications for humans
were glancingly considered by scientists- but not to worry, since these
plant estrogens were not a significant part of our diet. Neither were
they in the 1940s. But 50 years on the phytoestrogen-laden soybean has
entered the Western foodchain in a big way.
Despite the
experience with sheep (and decades of worrying animal studies) not a
single long term study has been undertaken on the effects of dietary
phytoestrogens on humans. No one has any real idea of the chronic
toxicity of these compounds. Yet over recent decades the food industry
has been discreetly adding estrogenic soy to basic foodstuffs –
including bread, pasta, sausages, and even frozen chicken pieces (check
for the ingredient labelled ‘vegetable protein’).
The
adulteration is now more overt, with phytoestrogen sold as dietary
supplements, added to some breads and breakfast cereals, and soon to be
put in margarine, muesli bars, biscuits and drinks. The time to take
notice is overdue. Some of our daughters, particularly if vegetarian,
may well be consuming plant estrogens at biologically active levels.
So just how
powerful are these compounds? Is there anything to worry about? When Dr
Fitzpatrick analysed processed foodstuffs for phytoestrogen levels
several years ago, he thought so. In 1995 he and three other
researchers warned in the New Zealand Medical Journal that soy infant
formula, for instance, contains three to five times as much
phytoestrogen as has been shown to disrupt the menstrual cycle of
women. The scientists recommended that supermarket sales of this
formula be stopped – advice not so far heeded by our health
ministry, although discussion is ongoing.
Dr
Fitzpatrick says his concerns about these new supplement products are
shared by US FDA estrogen research director, Dr Dan Sheehan, who only
last April warned against adding phytoestrogens to foodstuffs.
‘Phytoestrogens
can act on different sites of the body in different ways,’ says
Dr Fitzpatrick. ‘There are too many unanswered questions about
them. What if a young baby gets hold of these pills? Or a young girl
going through puberty? Where are the warnings?’
There is no
denying these products are potent. One herbal product containing plant
estrogens called Evanesce is so potent it is widely used in the US by
men wanting to change sex and grow breasts. (‘I’m now into
a full B… it is to the point where my wife and I know that I
need to start wearing a bra’ is the testimonial of one satisfied
customer.)
But quite
what the effects are on middle-aged women is not so clear. Nor is it
clear what dose of these products is safe to use, or what age group can
use them. Even sticking to low doses is no protection, says
Fitzpatrick, since scientists have little knowledge about dose-related
responses in humans and there is individual variation in
susceptibility.
Fitzpatrick
is not reassured by reminders that the Japanese consume soy safely,
saying that recent data shows their average daily phytoestrogen intake
is lower than previously thought – less than the amount that an
infant on soy formula consumes.
What if you
are getting a lot of phytoestrogens in your diet already? By taking
these pills you may be doubling the dose. Where is the warning that a
vegetarian diet or even a litre of soymilk already provides enough
phytoestrogen to elicit a biological response. You can be sure that
there will be a level at which phytoestrogens become acutely toxic,
never mind the chronic effects associated with continued daily
exposure.’
Asked about
the long-term effects, Fitzpatrick shrugs.
‘We
just don’t know. But it was established in the 1940s and 50s that
estrogens are bad news long-term. There is more awareness now that
these exogenous estrogens can promote cancer and cause endocrine
disruption.’
Overseas,
concerned researchers and regulators warn that manufacturers are
jumping the gun, seizing an apparent marketing opportunity before
safety has been established.
US
phytoestrogen researcher Dr Claude Hughes has warned women to consider
‘whether they or their offspring will experience any reproductive
or developmental effects due to exposure to these dietary hormone-like
phytochemicals.’
One US
study has shown a link between tofu consumption in mid-life and
dementia – possibly attributable to phytoestrogens affecting
estrogen sensitive brain cells.
In 1996 a
British government committee concluded that ‘the potential for
phytoestrogens to adversely affect infants is of particular concern
since it is possible that a hormonal imbalance in early life can
permanently affect sexual development and fertility’. Both that
body and the US Environmental Protection Agency have called for further
research on these ‘endocrine disruptors’.
Recently
the British Medical Research Council’s Institute of Environment
and Health researchers reviewed the scientific literature, looking only
at possible phytoestrogen benefits (reasoning that adverse effects were
already well established). Their 170 page report released last November
concluded that although some studies suggest some phytoestrogen
containing foods may have health benefits, ‘almost no evidence
exists to link these effects directly to phytoestrogens’.
As for
taking phytoestrogens in pill form, even an optimistic phytoestrogen
researcher like Dr Kenneth Setchell warns against them, saying
‘the potential dangerous effects from self-induced megadosing are
a concern’.
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REFERENCES:
Fundamental
and Applied Toxicology 1996; 29: 1-17,
Clinical
chemistry 1997; 43: 850,
Reproductive
Toxicology 1989; 3: 81-90,
Environmental
Health Perspectives 1988; 78: 171-175,
PSEBM 1995;
208: 92-97,
Institute
for Environment and Health Nov 1997 Report to MAFF on Phytoestrogens in
the Human Diet,
Lancet
1997; 350: 23-27,
NZMJ 24 May
1995; 208-209
Statement
by committee on toxicity of chemicals in food, consumer products and
environment (UK) 1996
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