It's been known for some time that soy isoflavones appear to benefit breast health for those with malignant tumors. However, this updated research now shows that isoflavones may extend a benefit for women beyond malignant tumors . . . the new study suggests a lower incidence of benign breast cysts as well.
The research, published in the December 2007 issue of Cancer Epidemiology Biomarkers & Prevention, adds to an ever-growing body of studies linking these phytochemicals to improved breast health. Dr. Johanna Lampe and her team from the Fred Hutchinson Cancer Research Center (Seattle) writes that benefits may also extend to fibrocystic breast conditions, a very common and benign condition characterised by lumpiness and discomfort in one or both breasts.
Population studies from heavy soy use countries have shown that a diet rich in soy is associated with fewer cases of breast cancer. This has been linked to the presence of soy isoflavones. In this case, the study was conducted in China where the researchers recruited 196 women with breast cancer, 304 women with benign breast condition, and 1,002 healthy, breast cancer-free age-matched controls from the Shanghai region. The benign conditions were further classified as proliferative (173 women) or nonproliferative (131 women).
Increased plasma levels of the isoflavones were associated with a reduced risk of both types of benign conditions, in addition to breast cancer. Indeed, the highest plasma levels (more than 76.95 nanograms per millilitre) were 74 per cent less likely to have breast cancer, and 60 per cent less likely to have benign conditions relative to women with the lowest average levels (less than 9.42 ng/mL).
"Isoflavone exposure was inversely associated with fibrocystic breast conditions and breast cancer, and the results suggest that effects on cancer risk occur early in carcinogenesis," wrote Lampe.