COLORECTAL-CANCER

Dietary factors are strongly associated with colorectal cancer incidence rates, but direct evidence for the involvement of diet in chromosomal damage and the adenoma-carcinoma sequence is awaited. In populations consuming high levels of meat and fat, the estimated risk for large bowel cancer attributable to low levels of non-starch polysaccharides (dietary fibre) is currently 35%. Risk is also inversely related to stool weight and, based on this, recent dietary guidelines recommend a population average intake of 18 g non-starch polysaccharides per day, which is a 50% increase for most Western societies, in order to reduce bowel problems including cancer. Starch is probably as important as non-starch polysaccharides in protection against colorectal cancer via its effect on fermentation and increased butyrate production.