Dietary chemoprevention of colorectal cancer

AIMS AND BACKGROUND: Colorectal cancer is the second cause of morbidity and death in Italy. Genetic and environmental factors, i.e. inappropriate nutrition, are strongly involved in the aetiology of colon cancer. In the present review the authors analyze the possible mechanisms by which certain nutritive factors may interfere with the complex process of carcinogenesis. METHODS: The authors identify studies by a literature search of Medline from January 1, 1970, through December 31, 2006. RESULTS: The mechanism of every protective compound is detailed, in particular the impact of antioxidant vitamins and minerals on tumor development. At present, the data suggest that vegetables are associated with lower risk and that their fbre content alone does not account for this association. Further, meat consumption is associated with an increased risk but this, too, is not explained solely by its fat content. Several microconstituents of the diet may be associated with reduced risk, including folate, methionine, calcium and vitamin D. Short chain fatty acids also contribute to colonic health. Nevertheless agricultural products contain several dangerous pesticides. Mutagenic compounds, particularly heterocyclic amines, produced when protein is cooked, plausibly explain the meat association. CONCLUSIONS: Healthy nutrition is a necessary but not sufficient condition for colon cancer prevention: accepted the feasibility of an accurate control on every patient's diet, fequently the difficulty encountered in nutritional chemoprevention is to establish individual metabolic profiles.