Dietary fiber was originally defined as "the remnants of plant cell walls not hydrolyzed by the alimentary enzymes of man" but the definition was subsequently modified to include "all plant polysaccharides and lignin which are resistant to hydrolysis by the digestive enzymes of man" ( 7). The fiber, both soluble and insoluble, is fermented by the luminal bacteria of the colon. High-fiber diets maintained for the long term reduce the incidence of colon cancer, but the mechanisms(s) involved rest on speculation, viz., its bulking action speeding colonic transit and reducing the absorption of luminal chemicals or the fiber absorbing the carcinogenic agents ( 5). (See also Chapter.43.)
Was this article helpful?