Lipid Digestion as a Colloid and Interface Phenomena

Abstract

The digestion of macronutrients, particularly lipids, inside the human gut can be viewed largely as a colloidal and interfacial phenomenon. Lipids exist as small colloidal particles within the digestive tract, such as oil droplets, micelles, and vesicles. The adsorption/desorption of bile salts, enzymes, biopolymers, and fatty acids at their surfaces impacts the rate and extent of lipid digestion, transport, and absorption. The transport of bile salts, enzymes, mixed micelles, and lipid particles through the gastrointestinal fluids also impacts lipid digestion. The aggregation state of lipid particles impacts the access of digestive enzymes to their surfaces, as well as their transport through the mucus layer. This chapter outlines some of the most important colloidal and interfacial phenomena that impact the gastrointestinal fate of ingested macronutrients, with an emphasis on lipids. It also shows how this knowledge can be used to create foods that can modulate macronutrient digestion, enhance bioactive bioavailability, and deliver bioactive agents to particular regions of the gut.