Mark Messina: Hello! I am Mark Messina. I am an Adjunct Associate Professor at Loma Linda University. And on behalf of The Soyfoods Council I will be talking about soy and breast cancer in adult women. Now, there is probably no more confusing and frightening soy related topic than soy and breast cancer. Many women fear eating soy because of their concern that soy may increase the risk of breast cancer. And women with the history of this disease may fear eating soy because of their concern that it may worsen their prognosis.
It's a little ironic that this is such a confusing and frightening issue for so many women, because much of the reason that the research community was first attracted to soy foods more than 20 years ago was because of evidence indicating that soy foods reduce the risk of breast cancer. Nevertheless, it's certainly understandable that so many women and even health professionals are confused about the impact of soy intake on breast cancer. That's because the animal and human studies have produced conflicting results. Of course it's the human studies that matter most, but some of the most important human studies have only recently been published, so many people and health professionals are not aware of their findings.
The concern about soy and breast cancer is based on the estrogen like effects of plant estrogens in soy or isoflavones, and the result form one particular mouse model. However, the isoflavones or plant estrogens in soy are different from the hormone estrogen and quite frequently the results from animal studies don't apply to humans. In contrast to the rodent research, the clinical studies show that neither soy foods nor the plant estrogens in soy adversely effect breast tissue, thereby supporting the safety of soy foods for women.
Furthermore, epidemiologic research actually indicates that soy food intake improves the prognosis of breast cancer patients. For example, a Chinese study involving over 5,000 breast cancer patients found those women who consumed about 2.
5 servings of soy foods per day were 30% less likely to die from their disease or suffer recurrence. In addition, a recently published U.
S. study that involved over 3,000 breast cancer patients found that those women who consumed about one serving of soy per day were about 50% less likely to die during the seven year follow up period. While it may be premature to specifically recommend soy foods to improve breast cancer prognosis, the evidence clearly no longer justifies advising against the use of soy by breast cancer patients and women at high risk of developing this disease.