Dietary fatty acids and colon cancer

Abstract

Although epidemiological evidence to support a preventive role for n-3 fatty acids in relation to colorectal cancer development is currently not convincing, there is a substantial and consistent literature based on a diverse range of animal models and in vitro studies to suggest that an increase in the ratio of n-3 to n-6 fatty acids in the diet is likely to be beneficial in this respect. Studies using intermediate markers of disease risk are strongly indicative of a protective effect of n-3 fatty acid consumption. The epidemiological evidence suffers from a lack of intervention studies with tumour as an endpoint, and in many of the observational studies, a low level of consumption or small ranges of intake combined with the fact that most studies were not designed specifically to identify dietary fat quality. A wide range of potential mechanisms has been investigated in relation to how different polyunsaturated fatty acids might modify risk, including alterations in luminal, paracrine and endocrine factors, as well as direct effects on cell division, differentiation and apoptosis. Keywords: n-3 fatty acids; colorectal cancer; nuclear receptors; prostaglandins inflammation