Eating soy during adolescence and adulthood protects women from premenopausal breast cancer

Scientists from Vanderbilt University School of Medicine in Nashville in conjunction with researchers from the National Cancer Institute and researchers in China evaluated the protective effects of soy, a source of isoflavones, on breast cancer risk. Soy intake was measured in adolescent and adult females.

In all 73,223 Chinese women were followed in the study for over 7 years on average. Soy consumption during adulthood significantly decreased the risk of premenopausal breast cancer. Soy protein was associated with a 59% decreased risk and soy isoflavones were associated with a 56% decreased risk. Eating soy foods in adolescence was associated with a 43% reduced risk. Soy foods did not seem to reduce the risk of postmenopausal breast cancer. The study is published in the June 2009 issue of the American Journal of Clinical Nutrition.