Soy Causes Cancer?

Does soy cause cancer?

There's been some evidence that the estrogens in soy can cause, or feed already existing, cancers. Soy contains high levels of compounds called phytoestrogens. These compounds occur in other foods, too, such as flaxseed, dates, peanuts and green beans. According to one food survey, flaxseed has almost four times as much phytoestrogen as soybeans per 100 grams. Soybeans have three times as much of the compound as tofu per 100g, and 33 times as much as 100g of soymilk.

After the discovery that hormone replacement therapy could potentially increase the risk of breast cancer because of its estrogen-stimulating effect, doctors became wary of allowing cancer patients to consume anything with estrogen-boosting properties. Many treatments for breast cancer include some sort of estrogen-blocking method, such as hormonal therapies like estrogen receptor blockers and aromatase inhibitors. Consuming too much high-phytoestrogen food can actually block the effects of these drugs, which is why doctors often advise those with breast cancer to stop eating soy.

If you don't have cancer, though, doctors say consuming moderate amounts of soy is very good for you. It can cut your risk of heart disease and osteoporosis. There are even studies indicating that a high-phytoestrogen diet can prevent certain kinds of cancer: this is based on the low instance of breast, endometrial and prostate cancer in Asia, where soy intake is high. The key to moderation, doctors say, is to get your soy through foods, and stay away from dietary supplements touting themselves as being high in phytoestrogens. These supplements could promote the risk of cancer.