Soy protein contains naturally occurring components called isoflavones. More than 100 clinical studies show that isoflavones do not adversely affect male health (lower testosterone) or female health (increased risk of breast and uterine cancer). Testosterone levels do not go down in men, and estrogen levels do not increase in women after consuming soy protein. Furthermore, these peer-reviewed studies show that soy protein may even help prevent cancer.
Soy is an excellent source of protein because it provides all 12 of the essential amino acids our bodies need daily. Our bodies can’t make essential amino acids, so they need to come from the foods we eat. Essential amino acids are the building blocks for the body to create the proteins it needs to make hormones and enzymes, as well as new cells for muscle, blood cells, brain tissue and many other crucial body functions. High-quality proteins are rich in essential amino acids and contain them in ideal ratios for use by our bodies. Soy protein and all animal proteins like those from milk are equal in quality.