The need for comprehensive diet studies to assess the relation of lipids to cancer.

Dietary lipids have been linked by both basic research and epidemiological evidence to the etiology of some cancers. It is yet unclear which lipid(s) may be active in the carcinogenic process, but one promising hypothesis concerns the interaction of cholesterol metabolites, considered a risk factor for colon cancer, and dietary fiber which may have a protective role. A multidisciplinary case control study currently underway is investigating the relationship and possible mode of action of fiber and bile acids on colon cancer. The study has epidemiological, biochemical, and pharmacological components that have been designed to integrate data on the intake and fate of lipids, dietary fiber, and other nutritional parameters in colon cancer cases and matched controls and in animal models. Subcomponents of the study deal specifically with the characterization of dietary fiber constituents and their in vivo effect on lipid metabolism.