Plant- and marine-derived n-3 polyunsaturated fatty acids have differential effects on fasting and postprandial blood lipid concentrations and on the susceptibility of LDL to oxidative modification in moderately hyperlipidemic subjects.
BACKGROUND
Dietary alpha-linolenic acid (ALA) can be converted to long-chain n-3 polyunsaturated fatty acids (PUFAs) in humans and may reproduce some of the beneficial effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cardiovascular disease risk factors.


OBJECTIVE
This study aimed to compare the effects of increased dietary intakes of ALA and EPA+DHA on a range of atherogenic risk factors.


METHODS
This was a placebo-controlled, parallel study involving 150 moderately hyperlipidemic subjects randomly assigned to 1 of 5 interventions: 0.8 or 1.7 g EPA+DHA/d, 4.5 or 9.5 g ALA/d, or an n-6 PUFA control for 6 mo. Fatty acids were incorporated into 25 g of fat spread and 3 capsules to be consumed daily.


RESULTS
The change in fasting or postprandial lipid, glucose, or insulin concentrations or in blood pressure was not significantly different after any of the n-3 PUFA interventions compared with the n-6 PUFA control. The mean (+/- SEM) change in fasting triacylglycerols after the 1.7-g/d EPA+DHA intervention (-7.7 +/- 4.99%) was significantly (P < 0.05) different from the change after the 9.5-g/d ALA intervention (10.9 +/- 4.5%). The ex vivo susceptibility of LDL to oxidation was higher after the 1.7-g/d EPA+DHA intervention than after the control and ALA interventions (P < 0.05). There was no significant change in plasma alpha-tocopherol concentrations or in whole plasma antioxidant status in any of the groups.


CONCLUSIONS
At estimated biologically equivalent intakes, dietary ALA and EPA+DHA have different physiologic effects.
Finnegan
Yvonne E
YE
Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, University of Reading, Reading, United Kingdom.
Minihane
Anne M
AM
Leigh-Firbank
Elizabeth C
EC
Kew
Samantha
S
Meijer
Gert W
GW
Muggli
Reto
R
Calder
Philip C
PC
Williams
Christine M
CM
D000975:Antioxidants / Q000032:analysis; D001786:Blood Glucose / Q000032:analysis; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage; D004281:Docosahexaenoic Acids / Q000008:administration & dosage; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage; D005215:Fasting; D005227:Fatty Acids / Q000097:blood; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage*; D005395:Fish Oils / Q000008:administration & dosage*; D005502:Food; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood*; D007328:Insulin / Q000097:blood; D015227:Lipid Peroxidation; D008055:Lipids / Q000097:blood*; D010743:Phospholipids / Q000097:blood; D010919:Placebos; D010938:Plant Oils / Q000008:administration & dosage*; D017962:alpha-Linolenic Acid / Q000008:administration & dosage
D000975:Antioxidants; D001786:Blood Glucose; D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D007328:Insulin; D008055:Lipids; D010743:Phospholipids; D010919:Placebos; D010938:Plant Oils; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid