In the last few years we have all heard a ton of conflicting recommendations on consuming soy. So what’s the real deal with soy?
Well first of all, there is good soy and bad soy. Consider soy that is genetically modified, moderately/highly processed, and/or not organic, to be “bad soy.” The effects of these types of soy products are unclear, but we do know that they do not offer the same benefits as good soy. “Good soy” is that which is organic and unprocessed (whole soy beans) or minimally processed (tempeh and tofu). Also, keep in mind that we are discussing a moderate intake of soy (3-4 servings/day). A healthy vegan diet involves consuming a wide variety of legumes, vegetables, fruit, seeds, nuts, and whole grains. More than 3 servings of soy per day, for most people, means that you will not be getting enough of a variety of other foods with important nutrients our bodies need to be healthy. Another tip is that I recommend using non-soy milks such as almond or coconut to “save” your soy servings for edamame, tofu, and tempeh so you are getting unprocessed soy with all the fiber and protein in tact!
That being said, let’s address the common concerns in regards to GOOD soy, based on the latest, most conclusive findings.
One question that’s simple to answer is, “Are soybeans really a quality protein source?” The answer is YES! Soybeans contain a 
large amount of high quality protein. They are also a complete protein, meaning they contain all the essential amino acids we need to build muscle. The great thing about soybeans is that you can consume the protein without the cholesterol that you get with meat.
Getting a bit more complicated and controversial is the question, “Does soy contain estrogen that could cause breast cancer in women and have adverse side effects on men?” Simply put, soybeans contain isoflavones, a class of “phytoestrogen” that has been found to have some meaningful health benefits to humans. For a more detailed explanation of the physiological effects of phytoestrogen in the human body click HERE. A majority of studies have shown that phytoestrogen from soybeans act as a protective factor for breast cancer as well as increase one’s chance for survival from breast cancer. In addition, it appears that soy may reduce the risk of other cancers, particularly prostate and colon cancers.
Another common concern is the belief that soy will cause thyroid dysfunction. Based on the available research, this is not the case. The issue comes only with people who have an existing thyroid condition for which they take medication. Soy can alter how some thyroid medications are absorbed in the intestines and it is therefore important to discuss your soy intake with the doctor upon being prescribed such medication.
Last, you may be wondering if soy is good for your heart. It seems that soy does have a positive effect on heart health. The isoflavones in soy have a dilating effect on our blood vessels, reducing blood pressure. Soy is also high in fiber, which is a protective factor for heart disease.
So there you have it… the simple, condensed answers to your common soy-related questions and concerns. The verdict, for most people, a moderate intake of organic, unprocessed soy is a healthful choice, although you certainly don’t NEED to consume soy in order to maintain a healthy, balanced plant-based diet.
I am providing a few solid resources that go into more detail on the latest research if you are interested in learning specifics.
nutritionfacts.org/video/breast-cancer-survival-and-soy/
nutritionfacts.org/video/how-much-soy-is-too-much/