Dr. Weil's pro soy position

[Guest guest]

A very recent pro soy opinion from Dr. Weil

http://www.drweil.com/app/cda/drw_cda.html-command=TodayQA-pt=Question-questionI\

d=76903.

Women's Health & Soy?

" 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 eliminate

soy foods from my diet? "

-- Anonymous

(Published 07/20/2002)

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

stimulate proliferation of cells with estrogen receptors, while others inhibit

it. High levels of isoflavones, the phytoestrogenic components of soy,

theoretically could 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

because soy contains stimulating phytoestrogens does not mean that the effect of

whole soy foods is stimulating to estrogen-sensitive cells. In fact, the

epidemiological evidence - that is, the evidence of incidence of diseases in

different populations - strongly suggests that soy protects women from

estrogen-dependent problems.

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 research

suggests 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 women

who 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 isoflavones

daily 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 the

outset, none of the women had uterine fibroids or endometriosis, both of which

are leading indications for hysterectomy and both of which are promoted by

estrogen. The researchers found that of the 1172 women participating in the six

year study, the hysterectomy rate was lowest among those whose diets contained

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

servings per 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

theoretical risks. 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. Weil