New research suggests that the herbal supplement red clover (Trifolium pretense) may blunt certain effects of the hormone DHEA, thus potentially eliminating any deleterious effects the hormone may have on the prostate.

DHEA is well known for its anti-aging properties; however some scientists are concerned that its use may increase the risk of prostate cancer.  Julia Arnonld, Ph.D., a researcher at the National Center for Complementary and Alternative Medicine (NCCAM) at the National Institutes of Health says that DHEA may be “potentially harmful in tissues containing inflammation or with early cancer lesions because the cells can induce DHEA to become more androgenic.” At present, men with prostate cancer, benign prostatic hyperplasia (BPH), other cancers, or a family history of these conditions, are advised against taking supplementary DHEA.

Researchers studying signaling between human prostate cancer cells and supporting stromal cells found that combining DHEA with transforming growth factor beta-1 increased testosterone production in the stromal cells, increased prostate specific antigen (PSA) protein secretion two to four-fold, and increased gene expression up to 50-fold in the cancer cells. However, no increases in testosterone production, PSA production, or gene expression, were observed when the cell cultures were treated with red clover isoflavones.

“Something is happening in the prostate tissue microenvironment that is illustrating a potential cancer prevention effect from this supplement,” says Dr Arnold. However, she adds that more work, both in the laboratory and in clinical studies, is needed to confirm the findings.

News release: New Lab Evidence Suggests Preventive Effect of Herbal Supplement in Prostate Cancer. American Association for Cancer Research (AACR). January 12th 2009.