In the adult digestive tract, lipases primarily break down fats into absorbable fragments in the lumen of the small intestine. Specifically, pancreatic lipase acts in the small intestine to hydrolyze dietary triglycerides into free fatty acids and monoglycerides

. Before pancreatic lipase acts, bile salts released by the liver emulsify fat droplets in the small intestine, increasing their surface area and making them accessible to lipase enzymes

. This emulsification is crucial for efficient fat digestion. The resulting free fatty acids and monoglycerides are then incorporated into micelles-small transport carriers formed by bile salts-which facilitate their movement through the watery mucus layer to the intestinal epithelial cells

. Inside these cells, the fragments are reassembled into triglycerides and packaged into chylomicrons, large lipoproteins that enter the lymphatic system for transport into the bloodstream

. In summary:

• Lipase digestion of fats occurs mainly in the small intestine lumen, catalyzed by pancreatic lipase.
• Bile salts emulsify fats to increase lipase efficiency.
• Fat digestion products (free fatty acids and monoglycerides) form micelles to reach intestinal cells.
• Inside intestinal cells, fats are reassembled and transported via lymph as chylomicrons.

This process enables fat absorption into the lymphatic system before entering systemic circulation