Nutraceutical Supplements and Prostate Cancer Prevention: A Systematic Review.

With the expansion of the nutraceutical market, dietary supplements have been increasingly investigated for prostate cancer (PCa) prevention, yet clinical findings remain inconsistent. This systematic review evaluates the clinical evidence of nutraceutical compounds and dietary modifications in PCa chemoprevention. After screening 736 records, 59 publications (15 randomized, 23 cohort, and 21 case-control reports) were included to evaluate dietary and supplemental intake of nutraceuticals in relation to PCa incidence. High-dose supplementation with vitamin E, selenium, and folic acid demonstrated either no preventive benefit or potential harm in several large studies. Specifically, selenium and vitamin E showed no benefit and possible harm in nutrient-replete men. High calcium and dairy consumption was associated with a modestly increased risk of PCa in several observational studies. Conversely, dietary lycopene from cooked tomato products was associated with a reduced risk of PCa in several observational studies. Soy isoflavones showed inverse associations in Asian studies, though results were inconsistent in Western populations. Furthermore, dietary intake of polyphenols, flavonoids, and tea was associated with reduced risk of advanced disease in selected observational studies. A pooled analysis of vitamin E trials showed no significant preventive benefit. Broader quantitative synthesis was not appropriate because of the limited number of comparable studies and substantial heterogeneity across studies. Current evidence does not support routine use of high-dose single-nutrient supplementation for PCa prevention. Potential benefits appear to be nutrient, population, and disease stage specific.