Benefits and Risks of Soy Protein

Soy has gotten a lot of press in recent years as a "wonder food." Soy products that used to be confined to health-food stores have popped up in the aisles of neighborhood grocery stores. But is soy really a miracle food? A good deal of research has been prompted by the fact that the Asian diet is high in soy protein and Asians are less prone to breast and prostate cancer, heart disease and osteoporosis. Research continues in many areas, but what has been proven is that soy protein, like most foods, has both benefits and risks.

One of the most conflicting reports on soy is whether it helps prevent or contributes to the development of breast cancer. Isoflavones, a type of phytochemical found in soy, mimic human estrogen. A great deal of research, according to the FDA, shows that the isoflavones in soy may help prevent breast cancer, and yet in women already predisposed to breast cancer due to genetics, the isoflavones may actually increase the risk. Women are advised to seek a doctor's advice before embarking on a soy-heavy diet.

Another highly touted benefit of soy is its ability to help lower cholesterol. In 1999 the FDA approved the use on soy-based foods of claims touting heart-healthy benefits, due to dozens of studies showing that soy protein helped lower levels of both total cholesterol and bad cholesterol. The studies showed that 25 grams of soy protein per day, from foods that are also low in fat, sodium and cholesterol, could help lower cholesterol between 3 and 5 percent. However in 2006 the American Heart Association released an advisory stating that "the direct cardiovascular health benefit of soy protein or isoflavone supplements is minimal at best."

Some studies have shown that soy's isoflavones help promote bone health; others show that soy is easily absorbed, and so calcium-fortified soy products help build the body's supply of calcium. Many of the studies have been done on animals using high doses of soy protein, so the effects on humans are still not clear.

There has been research into soy's effects on menopausal symptoms, due largely to the lower incidence of hot flashes and other menopausal symptoms among Asian women. While the United Soybean Board suggests that isoflavone supplements or foods rich in soy may reduce hot flash frequency, this remains inconclusive. Soy has also been shown to interfere with thyroid function in some people.

Studies continue on soy's benefits and risks. The risk of breast cancer is something that should be evaluated by each individual woman and her physician; however, other reported benefits are less risky. It may not stop hot flashes or prevent bone loss, but replacing fatty, high-cholesterol proteins like red meat with low-cholesterol, high-fiber soy products is certainly a good health practice, whether or not soy is truly a "wonder" food.