Intestinal absorption and lymphatic transport of eicosapentaenoic (EPA), docosahexaenoic (DHA), and decanoic acids: dependence on intramolecular triacylglycerol structure.

We compared the absorption of eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and decanoic acids in mesenteric lymph duct-cannulated rats following intragastric administration of two oils with different intramolecular triacylglycerol structures. One oil had a specific triacylglycerol structure with EPA and DHA located in the sn-2 position and decanoic acid in the sn-1 and sn-3 positions (specific M-n3-M) whereas the other oil had a random fatty acid distribution (random M-n3-M). The mol% (mol/100 mol total fatty acids) of fatty acids in the two oils was similar, with approximately 66 mol% of decanoic acid and 22 mol% of EPA and DHA. The lymphatic transport (microgram/min) of EPA and DHA as well as the mol% in the total lymph lipids were significantly (both P < 0.01) increased following intragastric administration of specific M-n3-M compared with random M-n3-M. The mol% of decanoic acid in the total lymph lipids was significantly (P < 0.01) higher after random M-n3-M compared with specific M-n3-M but the transport (microgram/min) of decanoic acid was not significantly different. We conclude that under our experimental conditions specific M-n3-M with EPA and DHA predominantly in the sn-2 position of the triacylglycerols was a more readily absorbed source of EPA and DHA and in this context should be investigated further for the potential use in clinical nutrition.