Absence of large bowel tumors in rats injected with 1,2-dimethylhydrazine and fed high dietary cellulose

The effect of very high concentrations of dietary cellulose against the development of colon tumors was investigated in 20 rats injected with conventional doses of 1,2-dimethylhydrazine. Ten of these rats were fed a regular (5%) concentration of cellulose and 10 were fed a very high (15%) concentration of cellulose. Rats fed regular cellulose developed a total of 16 tumors, nine in the small bowel and seven in the large bowel. In this group colonic tumors were large and invasive; 75% were carcinomas. Rats fed very high concentrations of cellulose had only four tumors, noninvasive and localized to the small intestine. Large bowels of rats fed high cellulose were completely devoid of neoplasms. This study suggests that very high concentrations of cellulose may suppress the development of large bowel tumors in rats. This could have significant implications concerning dietary protection against colon carcinogenesis.