RELATION OF VEGETABLE, FRUIT, AND GRAIN CONSUMPTION TO COLORECTAL ADENOMATOUS POLYPS

Previous studies suggest that colorectal cancer risk decreases with hi gher intake of vegetables, fruits, and grains. Few studies, however, h ave examined these factors in relation to occurrence of colorectal pol yps. The authors used case-control data from 488 matched pairs to eval uate associations of vegetables, fruits, and grains with polyps. Subje cts were southern Californians aged 50-74 years who had a sigmoidoscop y in 1991-1993. Diet in the year before sigmoidoscopy was measured wit h a food frequency questionnaire. Frequent consumption of vegetables, fruits, and grains was associated with decreased polyp prevalence. Spe cifically, the adjusted odds ratio comparing the highest with the lowe st quintile of intake for vegetables was 0.47 (95% confidence interval (CI) 0.29-0.76), for fruits was 0.65 (95% CI 0.40-1.05), and for grai ns was 0.55 (95% CI 0.33-0.91). The authors also found inverse associa tions for high carotenoid vegetables, cruciferae, high vitamin C fruit s, garlic, and tofu (or soybeans). After further adjusting for potenti ally anticarcinogenic constituents of these foods, high carotenoid veg etables, cruciferous vegetables, garlic, and tofu (or soybeans) remain ed inversely associated with polyps. These findings support the hypoth esis that high intake of vegetables, fruits, or grains decreases the r isk of polyps and suggest that any protective effects might reflect un measured constituents in these foods.