Fat Digestion: The Interaction of Lipid Digestion Products with Micellar Bile Acid Solutions

Abstract

Efficient fat absorption requires the rapid flux of poorly soluble and insoluble molecules through the very thick unstirred water layer coating the absorptive mucosa of the small intestine. Fat digestion involves a chemical event — the hydrolysis of ester lipids by lipase and a non-specific esterase; and a physical event — the micellar dispersion of these lipolytic products by bile acids. For some lipids, e.g. trioctanoin, only chemical hydrolysis is necessary since the digestive products are water soluble. Other insoluble lipids, such as cholesterol, are not altered chemically during digestion, but micellar solubilization is required for absorption.