Intestinal absorption of specific structured triacylglycerols

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To clarify the intestinal absorption pathway of medium-chain fatty acids from MLM-type structured triaclyglycerols containing both medium- and long-chain fatty acids, we studied the lymphatic transport of 1,3-dioctanoyl-2-linoleoyl-sn-glycerol (8:0/18:2/8:0), 1,3-didecanoyl-2-linoleoyl-sn-glycerol (10:0/18:2/10:0), and 1,3-didodecanoyl-2-linoleoyl-sn-glycerol (12:0/18:2/12:0) in a rat model. Safflower oil was used in the absorption study in order to compare the absorption of medium-chain fatty acids and long-chain fatty acids. The triacylglycerol species of lymph lipids were separated on a reversed-phase high performance liquid chromatograph (RP-HPLC) and identified by atmospheric pressure chemical ionization mass spectrometry. The composition of triacylglycerols was quantified by RP-HPLC with evaporative light scattering detection. The intact MLM-type triacylglycerols were detected in the lymph lipids after administration of the specific structured triacylglycerols (STAG). The recoveries of 8:0/18:2/8:0, 10:0/18:2/10:0, and 12:0/18:2/12:0 were 0.6%, 12%, and 5%, respectively. Several new triacylglycerol species were detected in the lymph lipids, including MLL-, LLL-, and MMM-type triacylglycerols. From the present study we conclude that the medium-chain fatty acids from STAG, in addition to absorption into the portal blood as free fatty acids, are absorbed by the same pathway as the conventional long-chain triacylglycerols, that is, they are hydrolyzed into free fatty acids, absorbed and activated into CoA, and reacylated into triacylglycerols in the enterocyte. The hydrolysis of MLM-type STAG is predominantly partial hydrolysis, whereas part of the STAG can also be hydrolyzed to free glycerol and free fatty acids.
Original languageEnglish
JournalJournal of Lipid Research
Volume42
Issue number5
Pages (from-to)792-798
Number of pages7
ISSN0022-2275
Publication statusPublished - 1 Jan 2001
Externally publishedYes

ID: 45479826