Diet and nutritional factors in the aetiology of colon cancer (review).

Epidemiological studies suggest that diet may be a major risk factor in the aetiology of colon cancer. Total fat, meat, animal protein and dietary fibre have received most attention. A high-fat - high-protein diet leading to increased faecal steroids has been implicated, but no active carcinogen derived from these has been isolated from human faeces. Alternatively, a refined, low fibre diet with decreased faecal bulk leads to increased large bowel concentration of carcinogens of co-carcinogens which contribute to the development of a malignant tumour. The aetiology of colonic cancer is probably multifactorial but a diet low in animal fat and protein and abundant in vegetables containing vitamin A and lignans may protect against colon cancer.