Intestinal bacteria and cancer.

Epidemiology indicates that diet plays an important part in the causation of colorectal cancer. We have postulated that this is because the diet determines the amount of substrate available for microbial metabolism to carcinogenic or co-carcinogenic products. We have studied a wide range of possible substrates and the evidence to date indicates that the most likely ones are the bile acids. Much more work is necessary before we can confirm or refute this postulated association.