title: Isomerization increases the postprandial oxidation of linoleic acid but not alpha-linolenic acid in men.
abstract: Human lipid intake contains various amounts of trans fatty acids. Refined vegetable and frying oils, rich in linoleic acid and/or alpha-linolenic acid, are the main dietary sources of trans-18:2 and trans-18:3 fatty acids. The aim of the present study was to compare the oxidation of linoleic acid, alpha-linolenic acid, and their major trans isomers in human volunteers. For that purpose, TG, each containing two molecules of [1-(13)C]linoleic acid, alpha-[1-(13)C]linolenic acid, [1-(13)C]-9cis,12trans-18:2, 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 CO(2) production and (13)CO(2) excretion were determined over 48 h. The pattern of oxidation was similar 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, alpha-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.
authors.affiliation: Unité de Nutrition Lipidique, Institut National de la Recherche Agronomique, 21065 Dijon, France.
authors.forename: L
authors.initials: L
authors.lastname: Bretillon
authors.forename: J M
authors.initials: JM
authors.lastname: Chardigny
authors.forename: J L
authors.initials: JL
authors.lastname: Sébédio
authors.forename: J P
authors.initials: JP
authors.lastname: Noël
authors.forename: C M
authors.initials: CM
authors.lastname: Scrimgeour
authors.forename: C E
authors.initials: CE
authors.lastname: Fernie
authors.forename: O
authors.initials: O
authors.lastname: Loreau
authors.forename: P
authors.initials: P
authors.lastname: Gachon
authors.forename: B
authors.initials: B
authors.lastname: Beaufrère
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D019787:Linoleic Acid / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D019518:Postprandial Period; D013237:Stereoisomerism; D013997:Time Factors; D014280:Triglycerides / Q000737:chemistry; D017962:alpha-Linolenic Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005231:Fatty Acids, Unsaturated; D014280:Triglycerides; D017962:alpha-Linolenic Acid; D002245:Carbon Dioxide; D019787:Linoleic Acid; D010100:Oxygen