Q: I have heard that Bowel Cancer can be prevented by introducing green tip bananas and aspirin into a healthy diet; is this true?

A:Colorectal cancer is the third most common cancer in both men and women in the U.S. The risk factors for it include age (>50y), a diet rich in fat & cholesterol and low in fibre, inflammatory bowel disease (especially ulcerative colitis), genetic predisposition (including hereditary polyposis and nonpolyposis syndromes) and alcohol consumption. Testing for fecal occult blood is at present the best screening method. Currently, there is a randomised phase II trial going on to compare the effectiveness of sulindac, aspirin, and ursodiol in preventing colorectal cancer being conducted jointly by the M.D. Anderson Cancer Center and National Cancer Institute in the U.S. and the findings are awaited. The Cochrane Review states that there is currently: No evidence from randomised controlled trials (RCTs) to suggest that increased dietary fibre intake will reduce the incidence or recurrence of adenomatous polyps within a two to four year period, Although the evidence from two RCTs suggests that calcium supplementation might contribute to a moderate degree to the prevention of colorectal adenomatous polyps, this does not constitute sufficient evidence to recommend the general use of calcium supplements to prevent colorectal cancer; and There was evidence from three pooled RCTs that aspirin (ASA) significantly reduces the recurrence of sporadic adenomatous polyps after one to three years. There is evidence from short-term studies to support regression, but not elimination or prevention of sporadic colorectal adenomas in Familial adenomatous polyposis. There is thus, only a limited role of aspirin and that too only in individuals suffering from any from of familial polyposis.