DOUBLE-BLIND-STUDY ON EFFECT OF PURIFIED CELLULOSE DIETARY FIBER ON 1,2-DIMETHYLHYDRAZINE-INDUCED RAT COLONIC NEOPLASIA

Abstract

The incidence, distribution, size and histopathology of grossly visible colonic tumors induced by parenteral administration of 1,2-dimethylhydrazine were examined in rats fed a chemically defined fiber-free diet or a nutritionally and calorically equivalent diet containing a purified fiber component, microcrystalline cellulose. Cellulose ingestion was associated with reduced numbers of animals involved with colonic neoplasia and a reduction in the total numbers of colonic tumors. This protective effect of cellulose appeared to be time dependent and associated with a shift in tumor distribution from the proximal colon to a more distal site. Cellulose fiber had no apparent effect on colonic tumor size, histopathology or the incidence of other tumors known to occur in this experimental animal model. Apparently fiber is an important protective agent against colonic neoplasia development. While the mechanism for this protective effect remains obscure, it appears to be temporally related to the duration of fiber ingestion and to a differential fiber effect on the luminal content or the mucosa of the proximal and distal colon.