Nutrition and colorectal cancer.

Environmental and genetic factors play an important role in the cause and pathogenesis of colorectal cancer. In addition to nutritional aspects, other environmental factors include physical exercise, energy intake, obesity, and parity. Dietary components currently under study are dietary fiber, fat, fruits, vegetables, and calcium. Intermediate markers of colonic proliferation, including bromodeoxyuridine and proliferating cell nuclear antigen incorporation, are being used to evaluate the response of the colonic epithelium to putative chemopreventative agents.