Fat absorption is uptake of digested lipids into intestinal epithelial cells, occurring by passive diffusion and carrier-mediated transport.
Absorbed lipids are esterified immediately inside the cell, maintaining the concentration gradient that drives further entry.
Mechanism of Absorption
Step 1 Bile salts, lecithin and monoglycerides emulsify dietary fat in the intestine, forming cylindrical micelles: aggregates of fatty acids, monoglycerides and cholesterol with hydrophobic ends at the centre.
Step 2 Micelles solubilize the lipids and carry them to the intestinal epithelial cell surface, where they disintegrate and the individual lipids passively diffuse into the enterocyte.