The epidemiology of diet and colorectal cancer: review and perspectives for future research using biological markers.

Case-control studies, and several prospective cohort studies, indicate that the risk of developing colorectal cancer is decreased in individuals who consume high levels of vegetables and fruits, and is possibly increased at high intake levels of meat and (saturated) fat. A new generation of prospective studies, following a multi-cohort design, is currently being set up in populations with diverse dietary intake patterns, and these may provide more detailed and more conclusive evidence on relations between nutritional factors and cancer risk. By including measurements of biomarkers in blood or tissue specimens, prospective epidemiological studies may also increase understanding of etiological pathways relating lifestyle factors to cancer development, and may thus help to identify nutritional factors that would need to be modified to prevent the disease.