Issues

Soy is rich in phytochemicals, and diets rich in soy products have been associated with a reduced risk of several cancers based upon epidemiologic studies and a variety of preclinical studies of pure soy phytochemicals. However, the number of clinical intervention trials that address these important dietary hypotheses are remarkably few, and findings from these studies have been mixed. Many questions regarding the types of food products to examine, as well as the optimal dose and duration of time necessary to impact human carcinogenesis and alter cancer risk remain uncertain. Evidence suggests that the absorption and metabolism of bioactive phytochemicals in soy is likely impacted by both host genetics and the microflora. The development of soy-based food products that are consistent, with known phytochemical composition, and easily incorporated into the diet with excellent compliance will allow many of the key questions to be addressed in clinical trials. In this study, a soy-based bread product has been tested in a phase II trial with men having prostate cancer. The cover figure depicts a stylistic cluster analysis of urinary soy isoflavonoid patterns in humans with four distinct metabolic patterns identified. See the article by Ahn-Jarvis and colleagues (beginning on page 1045) for more information.