Trial Information

Mammographic Density and Soy Isoflavones

This is a randomized, double-blind study, with two arms and 100 women in each arm.
Premenopausal women will be recruited and randomly allocated to take one of the two
different dietary supplements in pills daily for 2 years. The two supplements are soy
isoflavones (treatment) and placebo (carbohydrates). Both treatment and placebo pills will
contain multi-vitamins and minerals. Multiple blood, urine, and breast fluid samples will be
obtained before and during the dietary supplement periods and analyzed for biomarkers of
breast cancer risk. At baseline and after the intervention period, breast density and bone
density will be assessed by radiologic techniques. The efficacy of the dietary intervention
will be determined by comparing mean changes of serum markers for breast cancer risk,dense
breast tissue, and bone mineral density over the two year dietary intervention period in the
two supplement groups with adjustment for baseline values and individual patient
characteristics of interest. We predict that 2 years of soy isoflavone supplement will
reduce breast density, which may be explained by individual changes in serum markers of
breast cancer risk.