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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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