The role of dietary fiber in gastrointestinal disease.

The most consistent benefit of consumption of adequate dietary fiber is regular laxation; this effect alone justifies inclusion of fiber in the diet, in view of the enormous expenditure on drugs for digestive diseases. Dietary fiber has proved effective in decreasing symptoms of diverticular disease, Crohn's disease, and hemorrhoids in a limited number of small clinical studies. Fiber may also reduce the incidence of gallstone formation. Fiber is currently being touted as protection against colon cancer. However, the epidemiological and experimental data do not provide convincing evidence that fiber alone is a major determinant of risk for colon cancer. Furthermore, the data from international comparisons indicating that fiber is protective against colon cancer can be used in a similar simplistic manner to suggest that fiber may be a risk factor for stomach cancer. This should not dissuade individuals from obtaining adequate fiber from a wide variety of foods but should caution them against consumption of excessive amounts of fiber from a single source or from dietary supplements.