Medium chain fatty acids triglycerides, absorption

The small intestinal tract is the major place of digestion and absorption. Protein digestion reaches approximately 15% in the stomach, and in the lower intestine, the hydrolyzed fraction amounts to about 60%. Seventy percent of fats, 60% of carbohydrates, and about 30% of protein and peptide are absorbed within the duodenum. Within enterocytes, triglycerides are resynthesized from long-chain fatty acids and transformed into chylomicrons, which are transported via the lymphatic system, whereas short- and medium-chain fatty acids are directly transported into mesenteric and portal vein system. 

The absorption of vitamin E is relatively poor - only some 20% to 40% of a test dose is normally absorbed from the small intestine, in mixed lipid micelles with other dietary lipids. This absorption is enhanced by medium-chain triglycerides and inhibited by polyunsaturated fatty acids, possibly because of chemical interactions between tocopherols and polyunsaturated fatty acids or their peroxidation products in the intestinal lumen. Esters are hydrolyzed in the intestinal lumen hy pancreatic esterase and also by intracellular esterases in the mucosal cells. 

Odle J, Benevenga NJ, Crenshaw TD. Utilization of medium-chain triglycerides by neonatal piglets chain length of even- and odd-carbon fatty acids and apparent digestion/absorption and hepatic metabolism. J Nutr. 1991 121(5) 605-14. PubMed PMID 2019870. 

Jensen, C Buist, NRM Wilson, T. Absorption of individual fatty acids finm Long chain or medium chain triglycerides in very small infants. Am J Clin Nutr, 1986 43 745-51. 

Bauch, A.C., Ingenbleek, Y, and Frey, A. The usefulness of dietary medium-chain triglycerides in body weight control fact or fancy J. Lipid Res. 37, 708-725, 1996. earlier, H. and Bezard, J. Electron microscope auto radiographic study of intestinal absorption of decanoic and octanoic acids in the rat. J. Cell Biol. 65, 383-397, 1975. Bloom, B., Chaikoff, I.L., and Reinhardt, WO. Intestinal lymph as pathway for transport of absorbed fatty acids of different chain lengths. Am. J. Physiol. 166, 451 55, 1951. 

Figure 1. Schematic representation of dicarboxylic fatty acids (DCAs) synthesis and their degradation through L-PBE peroxisomal system, after medium chain triglycerides (MCT) liver absorption (adapted from Hardwick, 2008 Ding et al., 2013).

---