Metabolic epidemiology of dietary factors in large bowel cancer.

According to the hypothesis being tested by this laboratory, bacteria (in particular, certain clostridia) metabolize the bile acids to give unsaturated products that are important in the causation of colorectal cancer. In this paper, various dietary regimens are discussed in terms of their effect on the fecal steroid concentration and on the gut bacterial flora. The diets considered include high- and low-fiber, high- and low-meat, and high- and low-fat diets.