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.
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.
Y
Y
Angela Liou
Sheila M
SM
Innis
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