Soy May Help Prevent Prostate Cancer

FORT COLLINS, Colo.--Consuming a diet rich in soy may help prevent prostate cancer, according to a study published in the April issue of Biology of Reproduction (70, 4:1188-95, 2004) (www.biolreprod.org). When soy is digested, a molecule called equol is created in the intestine that blocks DHT, a potent androgen connected to prostate cancer growth.

The molecule does not prevent DHT from being produced; rather, it prevents DHT from functioning by inhibiting it from attaching to androgen receptors. Directly binding and inactivating DHT without influencing testosterone gives equol the ability to reduce many of the harmful effects of androgens without affecting the beneficial ones, said Robert J. Handa, Ph.D., senior author of the study. The novelty of equol is that it both inhibits androgren hormone and influences estrogen hormone action, added Edwin Lephart, Ph.D., another study author. We do not know of any other molecule that possesses these important biochemical properties.

Researchers studied equols effects in male rats with testes and male rats that had testes removed. When administered to intact male rats for four to seven days, equol reduced ventral prostate and epididymal weight. When administered to rats without testes (eliminating all DHT production), soy had no effect; when administered with DHT, equol prevented DHT from functioning as it normally would--as a stimulator of prostate growth.

Further studies have been begun by the researchers to assess equols potential as a treatment for other androgen-mediated conditions; the researchers have filed patent applications on equol and hope to commercialize the technology.