Update on Soy and Breast Cancer

With one in eight women being diagnosed with breast cancer every day, it's important to get the latest on facts on what to eat to prevent this deadly disease. The soy-breast cancer debate has been raging for close to 20 years, primarily because of the low rates of breast cancer seen in Asian women. Their diets contain many traditional soy foods including miso, soybeans, tempeh, tofu and soymilk. Western women (non-Asian) do not consume quite as much soyfood as Asian women, and tend to get their soy in the form of processed foods like protein bars, shakes, veggie burgers and meat substitutes.Soy contains plant compounds known as isoflavones, which are similar to the hormone estrogen. Isoflavones are known as phytoestrogens and have similar properties to estrogen, including the ability to bind estrogen receptors and act like estrogen in the body. Researchers believe phytoestrogens compete with estrogen in breast tissue to fight off cancer. However, excess estrogen in the body was a concern in that it could stimulate the growth of estrogen-sensitive tumors.More recent studies indicate that soy exposure early in life (i.e. during childhood and adolescence) is most likely protective in breast cancer prevention. In a study of over 73,000 Chinese women, premenopausal women that consumed a high level of soy foods during adolescence and adulthood had a much lower risk of breast cancer. The reduction is likely because isoflavones in soy that compete with estrogen to lower estrogen levels, which decreases the risk of breast cancer. Soy consumption may also improve the prognosis of breast cancer patients.Current research suggests 1-2 servings of soy foods per day are adequate to obtain the protective effects against breast cancer. As with other diet and health recommendations, whole foods such as tofu, edamame, soy milk or tempeh are likely better for you than soy supplements..