Which lipid source is absorbed directly into portal circulation, bypassing the lymphatic system?

Which lipid source is absorbed directly into portal circulation, bypassing the lymphatic system?

• A. MCT; absorbed directly into portal circulation bypassing lymphatics
• B. Long chain triglycerides require bile
• C. Fructooligosaccharides
• D. Cholesterol esters

Answer: (A)

Medium-chain triglycerides are absorbed directly into the portal circulation and bypass the lymphatic system. Their shorter fatty acid chains make them more water-soluble, so after intestinal digestion they cross enterocytes and enter the hepatic portal vein rather than being packaged into chylomicrons. Long-chain triglycerides, in contrast, require bile for emulsification, reform into triglycerides within enterocytes, are assembled into chylomicrons, and then travel via the lymphatic system through the lacteals before reaching the bloodstream. Fructooligosaccharides are carbohydrates, not lipids, and cholesterol esters are typically hydrolyzed and then enter via pathways that eventually contribute to chylomicron formation and lymphatic transport, not direct portal entry.

Medium-chain triglycerides are absorbed directly into the portal circulation and bypass the lymphatic system. Their shorter fatty acid chains make them more water-soluble, so after intestinal digestion they cross enterocytes and enter the hepatic portal vein rather than being packaged into chylomicrons. Long-chain triglycerides, in contrast, require bile for emulsification, reform into triglycerides within enterocytes, are assembled into chylomicrons, and then travel via the lymphatic system through the lacteals before reaching the bloodstream. Fructooligosaccharides are carbohydrates, not lipids, and cholesterol esters are typically hydrolyzed and then enter via pathways that eventually contribute to chylomicron formation and lymphatic transport, not direct portal entry.