Interaction of fiber and energy registration in experimental colon carcinogens.

Male, F344 rats were fed ad libitum diets in which the fiber was either 10% wheat bran or 4% cellulose. The diets contained equivalent amounts of fiber. Other groups were fed wheat bran or cellulose-containing diets which were pair fed to the controls to provide 10, 20, or 30% energy restriction (ER). Colon cancer was induced by five weekly feedings of DMH. After 28 weeks, colon tumor incidence in the ad libitum fed groups was: cellulose 70%, wheat bran 42%. At 10, 20, or 30% ER tumor incidence was 46, 29, and 21% in rats fed cellulose and 17, 17, and 21% in those fed wheat bran, respectively. The data confirm the greater protective action of wheat bran compared to cellulose.