Intestinal Absorption and Bioavailability of Dietary Lipids and Lipophilic Compounds

Abstract

The absorption pathway of dietar y lipophilic components is dif ferent from that of water-soluble molecules in the diet. Formation of micelles in the intestinal lumen is an impor tant 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 dif fusion or protein-mediated membrane transpor t. Susceptibilities to be absorbed and deposited in the body depend on the extent of lipophilicity of components. In this review, the absorption process of dietar y lipids, such as triglycerides and phospholipids, is briefly illustrated. Fur thermore, our research on the bioavailability of dietar y flavonoids, which possess relatively low lipophilicity, is also presented.