Intestinal lipid absorption and transport

The purpose of this review is to update the reader on our current knowledge of the digestion, uptake, and transport of dietary lipid. In particular, it discusses how intestinal lipid transporters may play a role in the uptake of lipids by the enterocytes, and how chylomicrons are formed in the enterocytes and packaged for export into the lymphatic system through exocytosis. The classification and properties of lipids is first described followed by a discussion of structured lipids and their role in human nutrition. Digestion of triacylglycerols takes place in the stomach aided by the enzyme gastric lipase. The origin and properties of lingual and gastric lipase are reviewed. Most digestion of triacylglycerols by pancreatic lipase occurs in the intestinal lumen. Similarly, digestion of cholesteryl ester and phospholipids also takes place in the intestinal lumen. This review describes in considerable detail the uptake of lipid digestion products by the enterocytes, particularly the role of recently identified lipid transporters. The intracellular trafficking and the resynthesis of complex lipids from the lipid digestion products are talked about, particularly within the context of the recently generated knockout mouse that lacks the key lipid reesterification enzymes. Finally, the mechanisms of the formation and secretion of chylomicrons is described and clinical disorders discussed.