Dietary n-6 fatty acids inhibit the incorporation of dietary n-3 fatty acids in thrombocyte and serum phospholipids in humans: a controlled dietetic study.
The effect of a high dietary intake of n-6 fatty acids (36 g daily) vs a low intake (4-6 g daily) on the incorporation of fatty acids from a dietary supplementation of n-3 fatty acids (6 g daily) was studied for 8 weeks in 15 healthy, normolipaemic volunteers. The importance of a high (43.6) vs a low (20.6) energy percentage from fat was also investigated in the participants on a low n-6 intake. Fatty acid analyses of serum and thrombocyte phospholipids showed a marked increase in docosahexaenoic acid (22:6 (n-3), DHA) and especially eicosapentaenoic acid (20:5 (n-3), EPA) in both the high and low n-6 groups after 14 days, but the changes were significantly greater in the low n-6 diet groups. Changes of the ratio between EPA and arachidonic acid (20:4 (n-6), AA) in phospholipids followed an identical pattern in serum and thrombocytes. This indicates that thrombocytes are influenced by the fatty acid composition in serum. The results showed that incorporation of n-3 fatty acids in phospholipids was reduced by a high intake of dietary n-6 fatty acids in the cells and lipid fractions studied. The observed effect of dietary n-6 fatty acids was independent of the energy percentage provided by dietary fat. In order to obtain an optimal effect of n-3 supplementation, the intake of linoleic acid has to be considered and kept at a low level. The serum content of cholesterol was unaffected, but the concentration of triacylglycerol was reduced during the supplementation period.
Grønn
M
M
Institute of Clinical Biochemistry, Rikshospitalet, Oslo, Norway.
Gørbitz
C
C
Christensen
E
E
Levorsen
A
A
Ose
L
L
Hagve
T A
TA
Christophersen
B O
BO
D000328:Adult; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood; D001792:Blood Platelets / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood*; D002849:Chromatography, Gas; D015118:Eicosapentaenoic Acid / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage* / Q000097:blood; D005260:Female; D006801:Humans; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000097:blood; D008297:Male; D008875:Middle Aged; D010743:Phospholipids / Q000032:analysis* / Q000378:metabolism; D011446:Prospective Studies; D014280:Triglycerides / Q000097:blood
D001095:Arachidonic Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D010743:Phospholipids; D014280:Triglycerides; D016718:Arachidonic Acid; D002784:Cholesterol; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid