Dietary linoleic acid has no effect on arachidonic acid, but increases n-6 eicosadienoic acid, and lowers dihomo-gamma-linolenic and eicosapentaenoic acid in plasma of adult men.
High intakes of linoleic acid (LA,18:2n-6) have raised concern due to possible increase in arachidonic acid (ARA, 20:4n-6) synthesis, and inhibition of alpha linolenic acid (ALA, 18:3n-3) desaturation to eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). In healthy men, 10.5% energy compared to 3.8% energy LA with 1% energy ALA increased plasma phospholipid LA and 20:2n-6, the elongation product of LA, and decreased EPA, with no change in ARA. However, LA was inversely related to ARA at both 10.5% energy and 3.8% energy LA, (r=-0.761, r=-0.817, p<0.001, respectively). A two-fold variability in ARA among individuals was not explained by the dietary LA, ARA, ALA, or fish intake. Our results confirm LA requirements for ARA synthesis is low, <3.8% energy, and they suggest current LA intakes saturate Delta-6 desaturation and adversely affect n-3 fatty acid metabolism. Factors other than n-6 fatty acid intake are important modifiers of plasma ARA.
Angela Liou
Y
Y
Nutrition Research Program, Child and Family Research Institute, Department of Paediatrics, University of British Columbia, 950 West 28th Avenue, Vancouver, B.C., V5Z 4H4, Canada.
Innis
Sheila M
SM
D015126:8,11,14-Eicosatrienoic Acid / Q000097:blood*; D000328:Adult; D016718:Arachidonic Acid / Q000097:blood*; D018592:Cross-Over Studies; D004032:Diet; D004537:Eicosanoic Acids / Q000097:blood*; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic
D004537:Eicosanoic Acids; C015876:eicosa-11,14-dienoic acid; D016718:Arachidonic Acid; D019787:Linoleic Acid; D015126:8,11,14-Eicosatrienoic Acid