Isomerization increases the postprandial oxidation of linoleic acid but not alpha-linolenic acid in men

Human lipid intake contains various amounts of trans fatty acids. Refined v egetable and frying oils, rich in linoleic acid and/or alpha -linolenic aci d, are the main dietary sources of trans-18:2 and trans-18:3 fatty acids. T he aim of the present study was to compare the oxidation of linoleic acid, alpha -linolenic acid, and their major trans isomers in human volunteers, F or that purpose, TG, each containing two molecules of [1(-13)C]linoleic aci d, alpha-[1(-13)C]linolenic acid, [1(-13)C]-9cis,12trans18:2, or [1(-13)C]- 9cis,12cis,15trans-18:3, were synthesized. Eight healthy young men ingested labeled TG mixed with 30 g of olive oil. Total CO2 production and (CO2)-C- 13 excretion were determined over 48 h, The pattern of oxidation was simila r for the four fatty acids, with a peak at 8 h and a return to baseline at 24 h. Cumulative oxidation over 8 h of linoleic acid, 9cis,12trans-18:2, al pha -linolenic acid, and 9cis,12cis,15trans-18:3 were, respectively, 14.0 /- 4.1%, 24.7 +/- 6,7%, 23.6 +/- 3.3%, and 23.4 +/- 3.7% of the oral load, showing that isomerization increases the postprandial oxidation of linoleic acid but not alpha -linolenic acid in men. - Bretillon, L., J. M. Chaldign y, J. L. Sebedio, J. P. Noel, C. M. Scrimgeour, C. E. Fernie, O. Loreau, P. Gachon, and B. Beaufrere. Isomerization increases the postprandial oxidati on of linoleic acid but not cr-linolenic acid in men.