Supplementation of postmenopausal women with fish oil rich in eicosapentaenoic acid and docosahexaenoic acid is not associated with greater in vivo lipid peroxidation compared with oils rich in oleate and linoleate as assessed by plasma malondialdehyde and F(2)-isoprostanes.
BACKGROUND
Although the replacement of dietary saturated fat with unsaturated fat has been advocated to reduce the risk of cardiovascular disease, diets high in polyunsaturated fatty acids (PUFAs) could increase lipid peroxidation, potentially contributing to the pathology of atherosclerosis.


OBJECTIVE
The objective of this study was to examine indexes of in vivo lipid peroxidation, including free F(2)-isoprostanes, malondialdehyde (MDA), and thiobarbituric acid reacting substances (TBARS), in the plasma of postmenopausal women taking dietary oil supplements rich in oleate, linoleate, and both eicosapentaenoic acid and docosahexaenoic acid.


METHODS
Fifteen postmenopausal women took 15 g sunflower oil/d, providing 12.3 g oleate/d; safflower oil, providing 10.5 g linoleate/d; and fish oil, providing 2.0 g EPA/d and 1.4 g DHA/d in a 3-treatment crossover trial.


RESULTS
Plasma free F(2)-isoprostane concentrations were lower after fish-oil supplementation than after sunflower-oil supplementation (P: = 0.003). When plasma free F(2)-isoprostane concentrations were normalized to plasma arachidonic acid concentrations, significant differences among the supplements were eliminated. Plasma MDA concentrations were lower after fish-oil supplementation than after sunflower-oil supplementation (P: = 0.04), whereas plasma TBARS were higher after fish-oil supplementation than after sunflower oil (P: = 0.003) and safflower oil (P: = 0.001) supplementation. When plasma MDA concentrations were normalized to plasma PUFA concentrations, significant differences were eliminated, but TBARS remained higher after fish-oil supplementation than after sunflower oil (P: = 0.01) and safflower-oil (P: = 0.0003) supplementation.


CONCLUSIONS
With fish-oil supplementation, there was no evidence of increased lipid peroxidation when assessed by plasma F(2)-isoprostanes and MDA, although plasma TBARS was higher than with sunflower-oil and safflower-oil supplementation.
Higdon
J V
JV
Department of Nutrition and Food Management, Oregon State University, Corvallis, USA.
Liu
J
J
Du
S H
SH
Morrow
J D
JD
Ames
B N
BN
Wander
R C
RC
D000368:Aged; D004032:Diet; D019587:Dietary Supplements; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000032:analysis; D015118:Eicosapentaenoic Acid / Q000032:analysis; D005227:Fatty Acids / Q000097:blood; D005395:Fish Oils / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D019787:Linoleic Acid / Q000032:analysis; D008054:Lipid Peroxides / Q000378:metabolism; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D019301:Oleic Acid / Q000032:analysis; D017698:Postmenopause; D014810:Vitamin E / Q000097:blood
D005227:Fatty Acids; D005395:Fish Oils; D008054:Lipid Peroxides; D014810:Vitamin E; D004281:Docosahexaenoic Acids; D019301:Oleic Acid; D008315:Malondialdehyde; D019787:Linoleic Acid; D015118:Eicosapentaenoic Acid; D015237:Dinoprost