Dietary intake of polyphenols and total antioxidant capacity and risk of prostate cancer: A case-control study in Iranian men.

BACKGROUND Prostate cancer (PCa) is one of the leading causes, globally, of cancer-related mortality. Previous studies have reported an inverse relationship between some food items or dietary patterns and prostate cancer risk. Polyphenols, as antioxidant and anti-inflammatory dietary components, have been associated with a reduced risk of PCa, whilst dietary indices such as total antioxidant capacity are good predictors of PCa risk. OBJECTIVE The purpose of this study was to conduct a case-control study on the association between polyphenol intake and DTAC (dietary total antioxidant capacity) and PCa risk in men. METHOD 205 hospital-based controls and 97 newly diagnosed PCa patients were asked about their dietary intakes using a validated questionnaire. The polyphenol contents (flavonoids, lignans, stilbenes and phenolic acids) of foods and beverages were calculated. TAC was obtained using a comprehensive database consisting of the total antioxidant content of more than 3000 food and beverages. Logistic regression was used to determine the odds ratios (OR), with 95% confidence intervals (CI), of PCa according to categories of polyphenol intake and TAC. RESULTS When comparing the highest and the lowest tertile of total polyphenol (OR: 0.12; 95% CI: 0.03-0.41), lignans (OR: 0.14; 95% CI: 0.04-0.41), phenolic acids (OR: 0.18; 95% CI: 0.05-0.57) and some flavonoid subgroups intake including flavan-3-ols (OR: 0.24; 95% CI: 0.08-0.67), flavanones (OR: 0.10; 95% CI: 0.03-0.31) and flavones (OR: 0.33; 95% CI: 0.12-0.87), we observed a significant decreasing trend in the risk of PCa (p for trend<0.05). CONCLUSION The results suggest that the consumption of some polyphenols can significantly reduce the risk of PCa.