Dietary Intakes of Retinol, Carotenes, Vitamin C, and Vitamin E and Colorectal Cancer Risk: The Fukuoka Colorectal Cancer Study

It has long been a matter of interest whether antioxidant vitamins are protective against colorectal cancer as well as human cancers in general, but epidemiological evidence is inconclusive. We investigated associations of dietary intakes of retinol and antioxidant vitamins with colorectal cancer risk in 816 incident cases of histologically confirmed colorectal cancer and 815 controls randomly selected for the Fukuoka colorectal cancer study in Japan. Dietary intakes were assessed by a PC-assisted interview regarding 148 food items. Statistical adjustment was made for body mass index, physical activity, calcium, and n-3 fatty acid intake and other factors. Retinol intake was significantly, inversely associated with colorectal cancer risk; the odds ratio for the highest vs. lowest was 0.55 (95% CI: 0.35, 0.88; P trend = 0.01) in women, but a modest increase in the risk was observed among men with the highest intake of retinol. Liver was the major source of retinol intake and showed similar associations wit...