Gastrointestinal tract: fat metabolism in the colon

Generally, only a small proportion of dietary fat that is consumed by man reaches the large intestine. Lipids in colonic digesta are derived from this undigested residue of dietary fat and partly from endogenous secretions and shedding of colonocytes. Intestinal bacterial lipases and phospholipases release fatty acids and various glycerides that may then be metabolized further to form products that have implications for intestinal health. Some clinical conditions result in increased fluxes of lipids to the large intestine, and, increasingly, slimming drugs that inhibit pancreatic lipases or adsorbants that enable fat to bypass the small intestine also result in large quantities of dietary lipids reaching the colon. The consequences of increased fat metabolism in the colon are as yet largely unknown.