Phytoestrogens may reduce the risk of prostate cancer.




Cancer Causes and Control

Related Monographs

Consumer Data: Prostate Cancer Soy Isoflavones
Professional Data: Prostate Cancer Soy Isoflavones


Scientists classify soy isoflavones from the plant Glycine max as phytoestrogens. Phyto is a Greek root word meaning plant, so phytoestrogens are plant-based compounds that have estrogen-like activity. Because they are structurally similar to estrogens, isoflavones exert weak estrogenic activity. Because of their estrogen-like effects, isoflavones have been studied for a wide spectrum of health benefits. Soybeans and soy foods like tofu are the best dietary source of isoflavones. However, many soy protein concentrates and soy products processed with alcohol may not contain isoflavones. A synthetically derived form of isoflavones, known as ipriflavone, is also available.

A recent study published in the March issue of Cancer Causes and Control stated that previous studies have demonstrated that phytoestrogens may protect against prostate cancer. This Swedish study investigated the potential link between dietary phytoestrogen intake and the risk of prostate cancer. This questionnaire-based study involved 1,499 men diagnosed with prostate cancer and 1130 healthy control subjects. Serum enterolactone (a phytoestrogen) levels were measured in a sub-group from 209 prostate cases and 214 controls. The results showed that a high intake of foods containing phytoestrogens was associated with decreased risk of prostate cancer. However, intake of lingans or isoflavones was not associated with a decreased risk. Intermediate levels of serum enterolactone were associated with the decreased risk. The authors concluded that this study supports the hypothesis that food high in phytoestrogens may be linked to a lower risk of prostate cancer.1


1. Hedelin M, et al. Dietary Phytoestrogen, Serum Enterolactone and Risk of Prostate Cancer: The Cancer Prostate Sweden Study (Sweden). Cancer Causes and Control. Mar 2006;17(2):169-180.