Cellulose and calcium lower the incidence of chemically-induced colon tumors in rats.

In a 30-week preliminary study and a follow-up 22-week study (2 x 2 factorial), dimethylhydrazine (DMH) injections effectively induced colon tumors in Fischer-344 rats. How this incidence of colon tumors might be affected by cellulose (preliminary study) or by calcium and folic acid (follow-up study) was examined. Cellulose in the diet appeared to provide some protection against DMH-induced colon tumors, but the protective effect of calcium was more evident; normal levels of calcium (500 mg per 100 g diet), but not of folic acid (0.1 mg per 100 g diet), provided protection against colon tumors. The effect due to calcium was observed whether viewed in terms of total number of tumors (p < 0.01) or number of tumors per tumor-bearing rat (p < 0.01).