Failure of bran to protect against experimental colon cancer in rats.

The ability of dietary fibre to prevent colon cancer was tested in rats injected with 1,2-dimethylhydrazine (D.M.H.), a substance which induces cancer of the colon. 60 rats were fed the same formula solid diet but allocated three different amounts of dietary fibre--20 were given 4.8% w/w crude fibre, 20 were given 20% w/w bran, and 20 received no fibre. Half of the animals in each fibre group received a course of subcutaneous D.M.H. and half were given subcutaneous saline. After a year's observation, there was no significant difference in the incidence of, or mortality from, colonic carcinoma between the D.M.H.-treated groups.