The study found a link between soy-rich diets consumed by Asian women in Singapore and reduced levels of an estrogen called estrone, the predominant form of estrogen in women following menopause. High estrogen levels have been shown to increase the risk for breast cancer among postmenopausal women.
Specifically, the study found that estrone levels were about 15 percent lower among women who consumed the highest amounts of soy protein. No other easily modifiable lifestyle factors analyzed by the scientists yielded such a dramatic hormone reduction.
"Results from this study support the hypothesis that high soy intake may reduce the risk of breast cancer by lowering endogenous estrogen levels, particularly estrone," said Anna H. Wu, the study's lead investigator and professor of preventive medicine at Keck School of Medicine of the University of Southern California, Los Angeles, Calif.
Also participating in the study, titled "Soy Intake and Other Lifestyle Determinants of Serum Estrogen Levels among Postmenopausal Chinese Women in Singapore," were Mimi C. Yu and Frank Z. Stanczyk, both at USC; and Adeline Seow and Hin-Peng Lee, with the Department of Community, Occupational and Family Medicine at the National University of Singapore.
Historically, breast cancer rates among Asians in Japan and China have been significantly lower than their female counterparts in the West. At one time, low-risk Asian women had one-sixth the breast cancer rate compared to high-risk whites in the United States and other parts of the western world. Reasons for this difference have remained largely unknown. However, Asians are clearl
Contact: Warren Froelich
American Association for Cancer Research