Soya Supplements May Be a Health Risk: German Consumer
Watchdog
RSSL -- Decemeber 6, 2007
The Federal Institute for Risk Assessment (BfR) Germany, has
undertaken a health assessment of isoflavone supplements. BfR found
that there is a lack of evidence to confirm the safety of such
supplements, yet there is some evidence to suggest that there may be
health risks. Long term studies of these extracts are needed to
evaluate the health implications.
Isoflavones are phyto-estrogens that may have a hormone like
(estrogen) effect on the body. Isoflavones are found predominantly in
soya beans (Glycine hispida max) and Red Clover (Trifloium pratense).
Daidzein, genistein and glycitein are the main isofavones found in
soya. Red clover is a mix of many isoflavone compounds; formononetin
and biochanin A are thought to be the main ones. Isoflavones may be
ingested naturally from food or as an isolated, fortified form in food
supplements.
One of the main groups who are targeted by isoflavone marketing is
post menopausal women. It is often claimed that such supplements can
ease the symptoms of the menopause, offering an alternative to hormone
replacement therapy. Other claimed advantages of the supplements are
heart, bone and breast health.
After reports of adverse events relating the taking of soya / red
clover supplements, BfR carried out a health assessment. This included
evaluating the scientific studies published to date. The reported
adverse events included itching, eczema, nausea, dizziness, abdominal
pain, skin rash and sweating. Conflicting reports and a lack of long
term studies make isoflavones a difficult subject to evaluate. Indeed
one study found that isoflavones stimulated breast cancer cells in
mice, while another found that women with a high soy diet generally
have lower rates of breast cancer.
BfR found that the assumed positive effects of isolated isoflavones
on menopausal complaints have not been sufficiently substantiated. The
reported adverse effects are not uniform and could be caused by an
allergic reaction to soya protein, or perhaps be symptoms of the
menopause. When administered at high doses in isolated or fortified
form, isoflavones impair the functioning of the thyroid gland and can
change mammary gland tissue.
The team conclude that it can not be ruled out that the estrogen
like effects of isoflavones could promote the development of breast
cancer. The necessary long term studies to prove the safety of
isoflavone containing products are not available. Nor is it currently
possible to reliably establish a dose which could be considered
safe.
It is worth noting that postmenopausal women are at increased risk
of breast cancer. The full report (23 pages) is available on the BfR
web site.
RSSL's Natural Products Laboratory can determine daidzein, genistein
and other soya isoflavones by HPLC. For more information please contact
Customer Services on Freefone 0800 243482 or e-mail
enquiries@rssl.com
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