title: Effect of dietary alpha-linolenic acid intake on incorporation of docosahexaenoic and arachidonic acids into plasma phospholipids of term infants.
abstract: The fractional conversion rates of plasma phospholipid alpha-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) to docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6), respectively, and the fractional rates of incorporation of 22:6n-3 and 20:4n-6 into plasma phospholipids were determined in 27 healthy 3-wk-old term infants who had received formulas with approximately 16% of fat as 18:2n-6 and 0.4% (n = 6), 1.0% (n = 11), or 3.2% (n = 10) as 18:3n-3 from birth. The infants were given a single dose of both [U-13C] 18:2n-6 and [U-13C] 18:3n-3 with a feeding, and blood samples were collected 8, 12, and 24 h afterward for determination of the isotopic enrichments of the [M + 18] isotopomers of plasma phospholipid fatty acids by negative chemical ionization gas chromatography/mass spectrometry. A simple precursor/product compartmental model was used to estimate fractional rates of conversion and incorporation. All infants converted 18:3n-3 to 22:6n-3 and 18:2n-6 to 20:4n-6. Although the fractional rate of conversion of 18:3n-3 to 22:6n-3 did not differ among groups, the fractional rate of incorporation of 22:6n-3 into the plasma phospholipid fraction was greater in infants who received 3.2% vs. 0.4% or 1.0% 18:3n-3 (4.1 +/- 2.2 vs. 1.6 +/- 1.5 or 2.0 +/- 1.0% of the plasma phospholipid 22:6n-3 pool daily). The fractional rate of conversion of 18:2n-6 to 20:4n-6 was less in infants who received the 3.2% 18:3n-3 intake (0.4 +/- 0.3% of the plasma phospholipid 18:2n-6 pool daily vs. 1.1 +/- 0.7% and 0.8 +/- 0.5% in those who received 0.4 and 1.0% 18:3n-3, respectively). The fractional rate of incorporation of 20:4n-6 into plasma phospholipid also was less in the 3.2% vs. the 0.4 and 1.0% 18:3n-3 groups (2.7 +/- 1.4% vs. 5.9 +/- 2.6 and 4.4 +/- 1.7%, respectively, of the plasma phospholipid 20:4n-6 pool daily).
authors.affiliation: USDA, ARS, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: T U
authors.initials: TU
authors.lastname: Sauerwald
authors.forename: D L
authors.initials: DL
authors.lastname: Hachey
authors.forename: C L
authors.initials: CL
authors.lastname: Jensen
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: R E
authors.initials: RE
authors.lastname: Anderson
authors.forename: W C
authors.initials: WC
authors.lastname: Heird
mesh_terms: D016718:Arachidonic Acid / Q000378:metabolism*; D004042:Dietary Fats, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000097:blood*; D017962:alpha-Linolenic Acid / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid