From the intestinal tract, which nutrient category is absorbed by the lymphatic system?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nucleic acids

Answer: (B)

Lipids are absorbed by the lymphatic system. After digestion, long-chain fatty acids and monoglycerides are reassembled into triglycerides inside enterocytes and packaged into chylomicrons. These large particles are too big for intestinal capillaries, so they enter the lacteals in the villi and travel through the lymphatic system. The lymph eventually drains into the bloodstream via the thoracic duct, bypassing the liver initially. In contrast, carbohydrates and proteins are taken up by the portal circulation via intestinal capillaries and go to the liver first, and nucleic acids follow a similar portal route.