Soy May Help Prevent Breast Cancer in Older Women
(HealthDayNews, 1/16/06)

Charles E. Wood of Wake Forest University, and team, hypothesized that the amount of estrogen in the body would change the effect of ingesting soy isoflavones on breast cancer risk. To test their theory, the investigators divided postmenopausal monkeys into a high and a low-estrogen group and then fed them four different diets, which included either no isoflavones or 60, 120 or 240 milligrams of isoflavones for 16 weeks each, plus a high or low dose of estrogen. When the researchers assessed the effect of the diets on such breast cancer markers as breast cell proliferation, they found a link between the soy-rich diet and reduced cancer risk in subjects with high estrogen levels.  The team also found that soy ingestion had no significant effect on low-estrogen subjects, allaying fears that soy's phytoestrogen effect might promote breast cancer in women with low estrogen. The scientists speculate that the isoflavones reduce cancer risk by connecting to the estrogen receptors and thereby depriving estrogen of these attachment points.

(Cancer Research, Jan. 15, 2006)