Soy Controversy

[Guest guest]

This comes from .

 

 

 

Q: Lately, I've read and heard that eating soy may increase the risk of breast cancer and make both endometriosis and fibroids worse. Should I eliminatesoy foods from my diet?

 

A:

 

I've been asked a lot lately about concerns such as yours. It is true that soy contains a mix of phytoestrogens - plant estrogens - some of which may stimulateproliferation of cells with estrogen receptors, while others inhibit it. High levels of isoflavones, the phytoestrogenic components of soy, theoreticallycould stimulate the growth of breast cancer and promote such estrogen-dependent conditions as benign fibroid tumors of the uterus and endometriosis.

 

I believe that physicians who advise women to avoid soy because of these theoretical concerns misunderstand the complexity of natural products. Just becausesoy contains stimulating phytoestrogens does not mean that the effect of whole soy foods is stimulating to estrogen-sensitive cells. In fact, the epidemiologicalevidence - that is, the evidence of incidence of diseases in different populations - strongly suggests that soy protects women from estrogen-dependentproblems.

 

Actually, soy's estrogenic effect is weak compared to the natural estrogen in women's bodies, only 1/100th to 1/1000th that of estradiol. Some researchsuggests that isoflavones may act in the body by blocking the more powerful effect of a woman's own estrogen. If true, this may explain why Japanese womenwho eat a lot of soy-based foods have only one-fifth the rate of breast cancer that occurs among Western women. Asian women consume 20-80 mg of isoflavonesdaily compared to less than 5 mg per day for American women.

 

An interesting study in Japan recently looked at whether diets high in soy foods increased the rate of hysterectomies among premenopausal women. At theoutset, none of the women had uterine fibroids or endometriosis, both of which are leading indications for hysterectomy and both of which are promotedby estrogen. The researchers found that of the 1172 women participating in the six year study, the hysterectomy rate was lowest among those whose dietscontained the most soy foods suggesting that soy foods seem to reduce the risk of fibroids and endometriosis.

 

I believe that soy foods such as edamame, tofu, tempeh and soy milk are much more likely to help you than hurt you. Therefore, I recommend one to two servingsper day, even to women with breast cancer. That amount will provide about 40 mg of isoflavones, enough to give you the benefits of soy without the theoreticalrisks. However, I do not recommend soy supplements because of their high isoflavone content and lack of evidence demonstrating their long-term safety.Nor do I recommend eating "designer foods" spiked with soy isoflavones.

 

Dr. Andrew Weil, M.D.

 

2002drweil.com. 2002 Inc. .