Understanding Phytoestrogens

At least a few times a week I am asked about the phytoestrogens found in soy and how they effect our bodies. Women are concerned that they may drive cancer and men are concerned they will turn into a women. So lets clear some of the misconceptions and fears about phytoestrogens.


What are phytoestrogens?


A phytoestrogen (phyto meaning plant derived) is a xenoestrogen (xeno meaning foreign) not generated within the endocrine system. They are also referred to as "dietary estrogen", it is a group of naturally occurring plant compounds. Because of the structural similarity with estradiol, they have the ability to cause effects on estrogen in the body.


Phytoestrogens can actually serve as one of the plants natural defense mechanisms working primarily to protect the plant from damaging fungus. Phytoestrogens are quite widespread in many plant-based foods. Soybeans are however one of the richest sources of phytoestrogens with the main one in soy being genistein.


How Phytoestrogens Work in the Body


For years many have come to think that by adding phytoestrogens into their diet they will increase their overall estrogen. This is a very common misconception. Many have looked to cultures that consume soy on a regular basis to determine that there are positive long-term effects of soy on overall health. These studies concluded that there was great benefit to consuming soy and that the phytoestrogens play a large roll in fighting and protecting against cancer and other diseases.


The incorrect assumption that the introducing phytoestrogens will raise your over all estrogen is often doe to the fact that many do not realize there are two different types of estrogen receptors in the body, alpha and beta. Unlike the estrogen you produce naturally, soy phytoestrogens will bind to and activate the Beta receptors and are much weaker than your natural estrogen. This is important because the alpha and beta receptors have different tissue distributions within the body and often function differently, and sometimes in opposite ways. There is still much to be understood in terms of this activation and the roll in breast cancer, but rather than increasing estrogen it has been concluded that there is more of a regulation or balancing effect, inhibiting the growth-promoting effects of actual estrogen especially in the breast.


These weaker estrogens even help to protect by blocking the stronger estrogens from things like plastic and pesticides.


While there have been some studies in mice that show a negative effect with the introduction if phytoestrogens, it turns out that the way we metabolize these phytoestrogens is very different from a rodent. On top of this the consumption levels needed to achieve these poor results are hard to achieve.


So what does this mean for you. Well according to an article by Written By Michael Greger M.D. FACLM on March 24th, 2020


"Pooling all of the results, soy food intake after breast cancer diagnosis was associated with both reduced mortality and reduced recurrence—that is, a longer lifespan and less likelihood that the cancer comes back. This improved survival was for women with estrogen receptor negative tumors and estrogen receptor positive tumors, and for both younger women and for older women."


Phytoestrogen Plant Synergy


While there are many studies on the benefits of phytoestrogens alone, we are always inclined to keep them in the synergy of the complementarity compounds that they are found in naturally. This means using the whole soybean and not just an isolated soy phytoestrogens. There is a synergy to the whole bean working together. Many of the other compounds like protease inhibitors, saponins, phytosterols and inositol hexaphosphate compounds, play a roll in how the phytoestrogens are absorbed and utilized.




Phytoestrogens can play a major roll in cancer, menopause and many other functions in the body. While many are misunderstanding their roll in the body there are others that are taking full advantage of their health promoting benefits. As always, making sure that you are getting a high quality and bioavailable form of phytoestrogens is key. As always, before introducing new things like pytoestrogens into your diet, It can be helpful to consult with your health care professional.