The aim of the randomized controlled double-blind crossover trial is to evaluate the effectiveness of two dietary supplements containing polyphenolic phytochemicals (isoflavonoid genistein and flavonoid quercetin) in comparison with placebo on the rate of increase in prostate-specific antigen (PSA). In addition, secondary objective is to evaluate the incidence of prostate cancer and to analyze malondialdehyde and protein carbonyle as indicators of the oxidative status.