Intestinal Absorption and Bioavailability of Dietary Lipids and Lipophilic Compounds

Abstract

The absorption pathway of dietary lipophilic components is different from that of water-soluble molecules in the diet. Formation of micelles in the intestinal lumen is an important step for the absorption of hydrophobic compounds. Such molecules cannot reach the intestinal epithelia without micellar formation because of the presence of the unstirred water layer overlying the brush border. Once reached the brush border, the components are taken up into the enterocytes either via simple diffusion or protein-mediated membrane transport. Susceptibilities to be absorbed and deposited in the body depend on the extent of lipophilicity of components. In this review, the absorption process of dietary lipids, such as triglycerides and phospholipids, is briefly illustrated. Furthermore, our research on the bioavailability of dietary flavonoids, which possess relatively low lipophilicity, is also presented.