Foods, nutrients and prostate cancer.

Objective: To examine the risk of prostate cancer associated with foods and nutrients, including individual fatty acids and carotenoids.

Methods: Population-based case-control study of 858 men aged <70 years at diagnosis with histologically confirmed prostate cancer of Gleason Grade 5 or greater, and 905 age-frequency-matched men, selected at random from the electoral rolls. Dietary intakes were assessed with a 121-item food frequency questionnaire.

Results: Inverse associations with prostate cancer were observed for (Odds ratio, OR, 95% confidence intervals, 95% CI for tertile III compared with tertile I) allium vegetables 0.7, 0.5-0.9; p trend 0.01, tomato-based foods 0.8, 0.6-1.0; p trend 0.03 and total vegetables 0.7, 0.5-1.0; p trend 0.04. Margarine intake was positively associated with prostate cancer 1.3, 1.0-1.7; p trend 0.04. The only statistically significant associations observed with nutrients were weak inverse associations for palmitoleic acid ( p trend 0.04), fatty acid 17:1 ( p trend 0.04), and 20:5 n-6 ( p trend 0.05); and a non-significant trend for oleic acid ( p trend 0.09). Neither total, nor beverage-specific, intake of alcohol was associated with risk.

Conclusions: Based on these findings, diets rich in olive oil (a source of oleic acid), tomatoes and allium vegetables might reduce the risk of prostate cancer.