Intestinal absorption of octanoic, decanoic, and linoleic acids: effect of triglyceride structure.

The influence of triglyceride structure on the intestinal absorption of specific triglycerides was investigated. A bolus of either a structured or a randomized oil was given to lymph-cannulated rats. The structured oil contained medium-chain fatty acids (MCFA) in the sn-1 and sn-3 position of the triglyceride, and linoleic acid (C18:2 n-6) in the sn-2 position, whereas in the randomized oil the same fatty acids were distributed randomly between the three positions. The absorption of MCFA was highest from the randomized oil, where approximately 33% of the MCFA were located in the sn-2 position. The absorption of C18:2 n-6 was highest from the structured oil, where C18:2 n-6 is located in the sn-2 position, indicating that the intestinal absorption is influenced by triglyceride structure, and that the absorption is enhanced for fatty acids located in the sn-2 position. Prior to lymph collection, the rats were fed either a fish oil or a vegetable oil diet. The absorption of C18:2 n-6 was highest in the rats previously fed the fish oil diet. The incorporation of the highly unsaturated fatty acids from the fish oil into the membrane phospholipids may thus influence the absorption of fat.