Mark Messina: Hello! I am Mark Messina, an Adjunct Associate Professor at Loma Linda University. And on behalf of The Soyfoods Council I will be talking about soy and breast cancer prevention. Breast cancer is the most common cancer among U.
S. women and the second leading cause of cancer death. However, breast cancer rates vary dramatically throughout the world and this difference in breast cancer rates is not due to genetic differences among populations. We know this because when women from low risk countries move to high risk countries, the successive one to two generations usually have a breast cancer rate similar to that of their adopted homeland. Furthermore, breast cancer rates can vary dramatically within the same population over a period of just several decades as a result of lifestyle and cultural changes. Low breast cancer rates in Japan were a primary reason the U.
S. National Cancer Institute first began to study the role of soy in preventing breast cancer more than 20 years ago. However, despite the extensive amount of research conducted over the past two decades, it's not possible to say with complete certainty that soy foods reduce risk of breast cancer, but there is intriguing evidence suggesting that soy foods are protective against this disease, but this may depend upon at which stage in life soy foods are first consumed. The evidence indicates that if soy foods are consumed early in life, that is during childhood and/or adolescence, they are very protective against breast cancer later on in life. Studies suggest that consuming as little as one serving of soy per day may reduce breast cancer risk by as much as 50%. Scientists postulate that the plant estrogens or isoflavones in soy cause changes in the developing breast that make breast cells permanently less likely to be transformed into a cancer cell later on in life. Now, we can't say for certain that eating soy when young reduces breast cancer risk, but there is no reason to wait for confirmation of this hypothesis before acting, because there is no disadvantage to females consuming soy when young. Soy foods are very nutritious and the amount needed for protection is only about one serving per day, which is very easy to incorporate into the diet.