Relationship of dietary cholesterol and cellulose in the prevention of colon cancer.

To study the effect of dietary cholesterol and cellulose on fecal sterol output and colon tumors in dimethylhydrazine-treated animals, rats were fed a basal diet supplemented with cholesterol (0.07% w/w) and/or cellulose (20% w/w). The addition of cholesterol alone to the basal diet failed to modify bile acid excretion or colon carcinogenesis. The addition of cellulose alone also failed to modify colon carcinogenesis, although it significantly decreased fecal bile acid concentration and increased daily bile acid excretion. However, when dietary cellulose was added to a cholesterol-containing diet, there was a significant decrease in colon tumor incidence (47% vs. 80%, P less than .05), accompanied by a significant increase in excretion of unmetabolized cholesterol. These data suggest that 1) the protective effect of certain fibers in colon carcinogenesis may be dependent on other dietary variables and 2) certain fecal neutral sterol profiles may be associated with colon tumor inhibition.