Soy and estrogen are related because soybeans contain a plant form of the hormone. Known as isoflavones , these phyto-estrogens are similar to those produced by the human body, although they are typically much weaker and thus do not cause as much of a response. The debate on whether soy-based estrogen results in infertility, certain cancers, and other disorders has not been resolved.
There is some evidence linking soy and estrogen consumption from eating soy-rich foods and the rise in infertility. While estrogen is needed for reproductive health, too much can lead to a host of gynecological problems. Studies are conflicting on whether or not soy has much of an impact on reproductive health in both men and women. Although the majority of research shows very little impact on the majority of individuals who eat or drink soy products in moderation, it may be beneficial to avoid soy for those who have issues with fertility.
Despite potential drawbacks, soy and estrogen can also be good for the body. There is some evidence to suggest that eating soy in moderation may help to alleviate menopausal symptoms and reduce the risk of certain cancers. That said, other links have been made between high soy consumption and breast cancer risk, so those at high risk for developing breast cancer should enjoy soy in extreme moderation. Additionally, consumers should speak with a doctor about any troubling symptoms they may be having.
Some debate has also been raised on the use of soy infant formulas, especially in infant boys. While studies are inconclusive on the impact phyto-estrogens in high enough enough quantities may have on the male body, many argue that it makes sense that estrogen could affect male fertility. Infants are sometimes given high amounts of soy in comparison to their body size and weight, since formula fed babies are given the formula as their main food source for the first year of life. For these reasons, soy formula should only be used once milk versions have been tried. Mothers who are breastfeeding may wish to avoid soy products.
The full relationship between soy and estrogen is not entirely understood. That said, there are many nations who eat soybeans and their byproducts as a main food staple, and birth rates are no lower than in nations who eat much less soy. Breast cancer rates are also generally not any higher than in countries who eat very little soy products.