High Soy Intake in Asians Associated with Lower Breast Cancer Risk

Natural estrogens from soy are associated with a decreased risk of breast cancer. However, don't load up on soy milk and cheese, which can cause a low thyroid. Use edamame (soy been pods) and tofu, in moderation, as they do in Asia.

This review and meta-analysis of 8 studies looked at the association between dietary soy intake and risk of breast cancer. Studies conducted among relatively high-soy-consuming Asian populations found that subjects consuming at least 20 mg per day isoflavones had a 29% reduced risk of breast cancer and those consuming approximately 10 mg/day had a 12% reduced risk relative to those consuming less than or equal to 5 mg/d isoflavones. Meanwhile, studies conducted among relatively low-soy-consuming Western populations did not find a protective effect of soy intake. The authors conclude, "Thus, the evidence to date, based largely on case-control studies, suggest that soy food intake in the amount consumed in Asian populations may have protective effects against breast cancer."

Reference:

"Epidemiology of soy exposures and breast cancer risk," Wu AH, Yu MC, et al, Br J Cancer, 2008; 98(1): 9-14.