title: Effects of dietary saturated and n-6 polyunsaturated fatty acids on the incorporation of long-chain n-3 polyunsaturated fatty acids into blood lipids.
abstract: Omega-3 polyunsaturated fatty acids (n-3PUFA) are better absorbed when they are combined with high-fat meals. However, the role of different dietary fats in modulating the incorporation of n-3PUFA in blood lipids in humans has not been previously explored. Omega-6 polyunsaturated fatty acids (n-6PUFA) are known to compete with n-3PUFA in the metabolic pathways and for the incorporation into phospholipids, whereas saturated fats (SFA) may enhance n-3PUFA incorporation into tissues.
  
  
  
  In a randomized parallel-design trial, we aimed to investigate the long-term effects of n-3PUFA supplementation in subjects consuming a diet enriched with either SFA or n-6PUFA on fatty acid incorporation into plasma and erythrocytes and on blood lipid profiles (total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides).
  
  
  
  Dietary supplementation with n-3PUFA co-administered with SFA for 6 weeks resulted in a significant rise in total cholesterol (0.46±0.60 mmol/L; P=0.020) and LDL-C (0.48±0.48 mmol/L; P=0.011) in comparison with combination with n-6PUFA. The diet enriched with SFA also induced a greater increase in eicosapentaenoic acid (2.07±0.79 vs 1.15±0.53; P=0.004), a smaller decrease in docosapentaenoic acid (-0.12±0.23 vs -0.30±0.20; P=0.034) and a similar increase in docosahexaenoic acid (3.85±1.14 vs 3.10±1.07; P=0.128) percentage in plasma compared with the diet enriched with n-6PUFA. A similar effect was seen in erythrocytes. N-3PUFA supplementation resulted in similar changes in HDL-C and triglyceride levels.
  
  
  
  The results suggest that dietary substitution of SFA with n-6PUFA, despite maintaining low levels of circulating cholesterol, hinders n-3PUFA incorporation into plasma and tissue lipids.
authors.affiliation: Nutraceuticals Research Group, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: C B
authors.initials: CB
authors.lastname: Dias
authors.affiliation: Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: L G
authors.initials: LG
authors.lastname: Wood
authors.affiliation: Nutraceuticals Research Group, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: M L
authors.initials: ML
authors.lastname: Garg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004032:Diet; D004041:Dietary Fats / Q000097:blood / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid / Q000097:blood; D004912:Erythrocytes / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D043371:Fatty Acids, Omega-6 / Q000009:adverse effects / Q000097:blood / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000097:blood; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000097:blood / Q000737:chemistry; D014280:Triglycerides / Q000097:blood; D055815:Young Adult
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D008055:Lipids; D010743:Phospholipids; D014280:Triglycerides; D002784:Cholesterol; D015118:Eicosapentaenoic Acid; C026219:docosapentaenoic acid