A double-blind study on the effects of differing purified cellulose and pectin fiber diets on 1,2-dimethylhydrazine-induced rat colonic neoplasia.

The incidence, distribution, size, and histopathology of colonic tumors induced by parenteral administration of 1,2-dimethylhydrazine were examined in rats fed a chemically defined fiber-free diet or nutritionally and calorically equivalent diets containing either 4.5 or 9.0% purified cellulose or pectin. This double-blind study indicates that cellulose is protective against experimental colonic neoplasia. Although the precise mechanism for this protective effect remains to be elucidated, it was not cellulose dose dependent and appeared to depend on administration during injection of carcinogen. Furthermore, this study provides strong evidence that identical amounts of cellulose and pectin fed as the sole source of fiber in chemically defined diets exert strikingly different effects in relation to development of intestinal neoplasia in this animal model.