Is soy really bad for you? Or should we all be eating more of it?
Unfortunately, if you read anything on the Internet, you might confuse yourself even more. That’s because some studies suggest soy might be linked to breast cancer, may destroy your thyroid, strip your masculinity, block vitamin and mineral absorption and may negatively affect your cognition. Whoa! If that’s the case, then we should all stay away from soy.
However, most of the studies were poorly conducted and interpreted out of proportion to what the study was capable of showing.
Soy and breast cancer: One of the studies done on mice that showed a link between soy intake and breast cancer did not take into account that mice metabolize soy isoflavones very differently than humans. Therefore, using mice would not be a suitable model for what happens in people. Some studies have shown the opposite linking soy to a decrease in breast cancer. Bottom line: Most experts agree that soy does not seem to increase or decrease the risk of breast cancer and is safe for consumption.
Soy and your thyroid: Soy foods do not cause harm to your thyroid for most people. Studies have shown that soy has no impact on thyroid function in healthy people. However, some soy foods may increase hypothyroidism in those with subclinical hypothyroidism.
Soy and masculinity: There is no real evidence to show that the plant estrogens in soy interfere with reproductive hormones in men. Studies show testosterone levels do not decline, estrogen remains within normal limits, and fertility does not decline in those consuming soy. However, soy may improve menopausal symptoms, specifically hot flashes in women.
Soy and vitamins/minerals: Raw soybeans contain phytic acid, which can interfere with the absorption of iron and zinc. However, soaking, fermenting, cooking, and other processing methods reduce phytic acid levels. Studies show no change in iron or zinc absorption from those consuming soy vs. other proteins, such as chicken, beef, or dairy.
Soy and your brain: One study done at the University of Hawaii in 2000 showed men that consumed two or more servings of tofu a week were at greater risk of cognitive decline and brain atrophy than those that did not. However, since this study, more research was done and showed no difference in cognitive function among individuals that consumed soy vs. dairy. Dutch scientists found no difference using similar tests as well.
Overall, soy is safe for consumption and may have a few health benefits as well, such as lowering cholesterol and reducing the risk of colon cancer when eaten in place of red meat.