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United States Department of Agriculture

Agricultural Research Service

Title: Metabolism of Stable-Isotope Labeled Palmitic and Linoleic Acids by Human Subjects

Authors
item Emken, Edward - RETIRED, USDA-ARS
item Adlof, Richard
item Duval, Sandra
item Becker, C - MARTEK BIOSCIENCES CORP
item Shane, M - ILLINOIS STATE UNIVERSITY
item Walker, P - ILLINOIS STATE UNIVERSITY
item Byrdwell, Wm - FORMER ARS EMPLOYEE

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: April 25, 2000
Publication Date: N/A

Technical Abstract: To investigate the effect of triacylglycerol (TAG) structure on the metab- olism of 16:0 and 18:2n-6, two diet groups of male subjects (n=23) were provided low fat (24 g/d) diets supplemented with 61 g/d of native lard or randomized lard for two 28-day diet periods. The diet treatments did not affect serum Tag, cholesterol lipoprotein concentrations. At the end of the second diet period, two subjects from each diet group were dosed with triacylglycerols containing deuterated palmitic and linoleic acids located at specific acyl positions. The deuterated 16:0 and 18:2n-6 fatty acids were equally well absorbed, and neither diet nor TAG acyl position influenced total absorption. The deuterated fatty acids in the 2-acyl position of the fed triacylglycerols were 85 +/-4.6% retained in chylomicron TAG. In chylomicron TAG, extensive migration of palmitic acid from the sn-2 acyl position occurred. Migration was minimal when the 2H- fatty acids were initially absorbed in the preferred chylomicron TAG sn positions. Triacylglycerol structure influenced accretion of 2H-16:0 and 2H-18:2n-6 at the 1-acyl position of phosphatidylcholine. The major labeled metabolites detected were 18:0, 20:3n-6 and 20:4n-6. Accumulation of 2H-20:4n-6 was the only metabolite influenced by diet and TAG sn position. The effects of TAG sn position on the metabolism of labeled 16:0 and 18:2n-6 were minor and suggest that TAG sn position has limited physiological importance.

Last Modified: 8/1/2014
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