What portion of the small bowel is dietary fat absorbed in?

• A. Distal small bowel: ileum and jejunum
• B. Proximal colon: duodenum and proximal jejunum
• C. Proximal small bowel: duodenum and proximal jejunum
• D. Entire small bowel

Answer: (C)

Most dietary fat absorption happens in the proximal part of the small intestine—the duodenum and proximal jejunum. After fats are emulsified by bile and digested by pancreatic lipase, the resulting fatty acids and monoglycerides form micelles that deliver them to enterocytes in these early intestinal segments. Inside the enterocytes, fats are re-esterified and packed into chylomicrons, which enter the lymphatic system. The distal small intestine, especially the ileum, is more involved in reabsorbing bile acids and some fat-soluble vitamins, while the colon does not absorb dietary fat. That makes the proximal small bowel the primary site for fat absorption.