title: Dietary oils and FADS1-FADS2 genetic variants modulate [13C]α-linolenic acid metabolism and plasma fatty acid composition.
abstract: BACKGROUND
  Desaturation of dietary α-linolenic acid (ALA) to omega-3 (n-3) long-chain fatty acids (FAs) is mediated through FA desaturases (FADS1-FADS2) and may be influenced by dietary FA composition.
  
  
  OBJECTIVE
  We investigated the effects of diets enriched in flaxseed oil (FXCO) or high-oleic acid canola oil (HOCO) compared with a Western diet (WD) and FADS1-FADS2 single nucleotide polymorphisms (SNPs) on plasma FAs and [U-(13)C]ALA metabolism.
  
  
  METHODS
  In a randomized crossover design, 36 hyperlipidemic subjects consumed 3 isoenergetic diets enriched in FXCO (20.6 g ALA/d), HOCO (2.4 g ALA/d), or WD (1.3 g ALA/d) for 4 wk. On day 27, blood was sampled 0, 24, and 48 h after the subjects (n = 26) consumed 45 mg [U-(13)C]ALA. The subjects were genotyped for 4 FADS SNPs.
  
  
  RESULTS
  FXCO increased (P < 0.001) plasma ALA, EPA, and docosapentaenoic acid (DPA), with no change in DHA compared with the HOCO or WD diets. At 24 and 48 h, [U-(13)C]ALA recovered as plasma [(13)C]EPA and [(13)C]DPA were lower (P < 0.001) after the FXCO diet than after the HOCO and WD diets. No change in [(13)C]DHA was observed between diets. Minor allele homozygotes of rs174545, rs174583, rs174561, and rs174537 had lower (P < 0.05) plasma EPA, arachidonic acid (AA), EPA/ALA, and AA/linoleic acid compositions and lower (P < 0.05) plasma [(13)C]EPA enrichment at 24 and 48 h in comparison with carriers of the major allele after all diets. SNPs were not associated with plasma composition of DHA or [(13)C]DHA enrichment.
  
  
  CONCLUSIONS
  An increase in ALA intake resulting in increased plasma EPA composition may be cardioprotective, especially in minor allele homozygotes. This trial was registered at www.clinicaltrials.gov as NCT00927199.
authors.affiliation: Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Canada.
authors.forename: Leah G
authors.initials: LG
authors.lastname: Gillingham
authors.forename: Scott V
authors.initials: SV
authors.lastname: Harding
authors.forename: Todd C
authors.initials: TC
authors.lastname: Rideout
authors.forename: Natalia
authors.initials: N
authors.lastname: Yurkova
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Cunnane
authors.forename: Peter K
authors.initials: PK
authors.lastname: Eck
authors.forename: Peter J H
authors.initials: PJ
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D016718:Arachidonic Acid / Q000008:administration & dosage / Q000097:blood; D015415:Biomarkers / Q000097:blood; D018592:Cross-Over Studies; D000090943:Delta-5 Fatty Acid Desaturase; D004032:Diet; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000097:blood; D004281:Docosahexaenoic Acids / Q000008:administration & dosage / Q000097:blood; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage / Q000097:blood; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005227:Fatty Acids / Q000097:blood*; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage / Q000097:blood; D005260:Female; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage / Q000097:blood; D008043:Linseed Oil / Q000008:administration & dosage; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D019301:Oleic Acid / Q000008:administration & dosage / Q000097:blood; D020641:Polymorphism, Single Nucleotide; D000074262:Rapeseed Oil; D016037:Single-Blind Method; D055815:Young Adult; D017962:alpha-Linolenic Acid / Q000008:administration & dosage* / Q000097:blood*
chemical_list: D015415:Biomarkers; D000090943:Delta-5 Fatty Acid Desaturase; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D008055:Lipids; D000074262:Rapeseed Oil; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D019301:Oleic Acid; D008043:Linseed Oil; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid; D044943:Fatty Acid Desaturases; C000716847:FADS1 protein, human; C533241:FADS2 protein, human