Do Phytoestrogens Cause Breast Cancer?

do phytoestrogens from soy cause cancer

Should I Avoid Phytoestrogens?

The short answer is, no.

What are phytoestrogens?

These are plant compounds that can act like estrogen in our bodies.  They are found naturally in a wide array of foods including soy beans, kidney beans, flaxseeds, sprouts, cabbage, spinach, soybeans, grains, hops, garlic, onion, plums, pears, apples, grapes and berries.

Can phytoestrogens cause or worse hormone-related conditions like cancer or endometriosis?

All of the present evidence appears to point toward a protective effect from phytoestrogens. Although phytoestrogens can bind to estrogen receptor sites and stimulate estrogen-like activity, they are very weak.  Much weaker than your own estrogen and weaker than chemical estrogens like BPA from plastic, pesticides and herbicides. Because they are very weak, phytoestrogens may exert a protective effect against cancer.  They do so by taking up receptor sites that otherwise these other very potent estrogens could bind to.  This is a similar action to the breast cancer drug, Tamoxifen. Any research on soy and breast cancer, for example, suggests a protective effect.  Curcumin, an extract from turmeric, also contains phytoestrogens.  It has a multitude of benefits for breast cancer patients.
I’m not saying you should go out and consume copious amounts of soy, but I also wouldn’t fear tofu or edamame.
If you would like to read more about phytoestrogens, there is a more detailed paper here: Phytoestrogens: food or drug?