Steve Bui, M.S.
A much more popular part of the diet in East Asian countries, soy has been slowly increasing in popularity in the western diet as well. The soy bean is part of the legume family and can be grown in many different environments. Once mature, soy beans can be converted into a wide variety of other forms including: tofu, miso, oil, flour, meat substitute, and milk.
Soy beans are considered to be one of the most nutritionally dense foods available. The Food and Drug Administration has officially reported that consuming 25 grams of soy protein daily can be very beneficial. It is one of the few vegetable products that have been labeled as a “complete protein,” meaning that it contains significant amounts of every essential amino acid required. Essential amino acids are amino acids that the body cannot naturally produce on its own, and have to be obtained through diet, and are necessary to body function. In addition to it being an excellent source of protein, soy also has a high fiber content. In one cup of soybeans, one could potentially be getting 10 grams of fiber and 25-30 grams of high quality protein. Other benefits of soy include decreasing LDL (bad cholesterol) and overall cholesterol levels, decreasing blood pressure, reducing osteoporosis, and aiding in menopausal symptoms.
Recently soy has come under some scrutiny for potentially affecting hormonal levels in individuals. The most common hormone of concern is estrogen. Soy has a high content of isoflavones, which in the body act similarly to weak estrogens. The fear arose that excess levels of isoflavones would cause increased risk for breast cancer and other estrogen-based hormonal problems. Some men fear increased soy intake would cause feminization and decreased sperm count. Current research on soy in regards to these risks has been mixed; however, the majority of the studies show no increased risk for breast cancer in women (even women who have had breast cancer previously), and no effects on men. One study followed over 20,000 Japanese women for over 10 years. These Japanese women exhibited some of the highest amounts of dietary soy consumption in the world but consequently were shown to have some of the lowest risks for breast cancer.
At this point, it is difficult to make one universal statement about whether soy is “good” or “bad.” It has been suggested that women who have had breast cancer in the past should avoid high consumption of soy; however, highly credible studies have reported otherwise. It is important to understand that soy does not have to be avoided. With moderate consumption, one can enjoy all the health benefits of soy without worry.
- Messina M. Insights Gained from 20 Years of Soy Research. J. Nutr. December 1, 2012 vol. 140 no. 1222895-22955.