Large bowel cancer: prospects for control.

The incidence of large bowel cancer, a major cancer in the western world, varies significantly for different segments of the colon as a function of geographic pathology, but the rectal cancer incidence shows smaller distinctions in different countries. Cancer in the descending and sigmoid colon relate to western lifestyle, particularly the high level of dietary fat (40-45% of calories). The lower risk seen in Finland is associated with a high intake of cereal fibers. The current information base with regard to the nutritional factors that show an enhancing effect by high-fat intake and protective effects of agents increasing stool bulk, such as cereal and vegetable fibers, is sufficiently convincing to allow recommendations for intervention trials using fat and fiber. Optimal levels for disease prevention are different from normally accepted and traditional intakes of fat and fiber, and measurable parameters such as serum cholesterol levels, stool weight, fecal bile acid concentration, and perhaps fecal mutagens reflect averages derived from the intake of a high-fat, low-fiber diet that are not optimal. Optimal recommendations are for a dietary level of 20-25% of fat calories and about 30 g of total fiber from whole grain cereals and cruciferous vegetables. Such measures (low-fat, high-fiber) have the advantage of having no obvious adverse effects and can be implemented now on a public and personal basis while additional options in preventive medicine are being explored.