ABSTRACT
Soybeans are unique among the legumes because they are a concentrated source of isofl avones which have esterogenic properties, and the isofl avone genistein infl uences signal transduction. Soy foods and isofl avones have received considerable attention for their potential role in preventing and treating cancer and osteoporosis. The low breast cancer mortality rates in Asian countries and the putative antiestrogenic effects of isofl avones have fueled speculation that soy food intake reduces breast cancer risk. The available epidemiological data are limited and only weakly supportive of this hypothesis, particularly for postmenopausal breast cancer. Further, the data suggesting that soy or isofl avones may reduce the risk of prostate cancer are more encouraging (Messina, 1999). The weak estrogenic effects of isofl avones and the similarity in chemical structure between soy isofl avones and the synthetic isofl avone iprifl avone, which increases bone mineral density in postmenopausal women, suggest that soy or isofl avones may reduce the risk of osteoporosis. Rodent studies tend to support this hypothesis, as do the limited preliminary data from humans. Soybean consumption has also been linked to reduced risk for cetrain cancers and diseases of old age. The health benefi ts associated with soybean consumption have been linked to the action of isofl avonoids, the major phenolic phytochemicals present in soybean. Isofl avonoids possess numerous biological activities that may support chemoprevention through promotion of apoptosis in diseased cells.
