title: Total fat intake modifies plasma fatty acid composition in humans.
abstract: Plasma fatty acid composition reflects dietary fatty acids. Whether the total fat content of the diet alters the fatty acid composition of plasma phospholipid, cholesteryl ester, triacylglycerol and free fatty acids is unknown. To evaluate the effects of low versus high fat diets on plasma fatty acids, a 12-wk, randomized, crossover, controlled feeding trial was conducted in healthy men and women with isoenergic low fat (20% energy) and high fat (45% energy) diets containing constant proportions of fatty acids. Ten subjects consumed one experimental diet for 28 d, their usual diet for 4 wk and the alternate experimental diet for 28 d. Endpoint measures of plasma fatty acids were determined at the end of each experimental period. The effects of the two diets were compared within subjects by analysis of variance. Plasma fatty acids (%) varied in response to total dietary fat with significantly greater total polyunsaturated fat, (n-6) and 18:2(n-6) levels in phospholipids and cholesteryl esters after high fat dietary consumption. The low fat diet was associated with significantly greater total (n-3) fatty acids, 20:5(n-3) and 22:6(n-3) levels in plasma phospholipid fatty acids and cholesteryl esters. Consumption of a low fat diet alters fatty acid patterns in a manner similar to that observed with feeding of (n-3) long-chain fatty acids. This change is likely related to decreased competition for the enzymes of elongation and desaturation, with reduced total intake of 18:2(n-6) favoring elongation and desaturation of available (n-3) fatty acids.
authors.affiliation: General Clinical Research Center, Hormel Institute and. Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota 55455, USA. raatz@mail.ahc.umn.edu
authors.forename: S K
authors.initials: SK
authors.lastname: Raatz
authors.forename: D
authors.initials: D
authors.lastname: Bibus
authors.forename: W
authors.initials: W
authors.lastname: Thomas
authors.forename: P
authors.initials: P
authors.lastname: Kris-Etherton
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002788:Cholesterol Esters / Q000097:blood; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000008:administration & dosage* / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000097:blood; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood; D014280:Triglycerides / Q000097:blood
chemical_list: D002788:Cholesterol Esters; D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D014280:Triglycerides