Flaxseed oil supplementation increases plasma F1-phytoprostanes in healthy men.
Supplementation with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has been reported to reduce lipid peroxidation products formed from arachidonic acid (F(2)-isoprostanes) in healthy humans, as well as in those under oxidative stress. alpha-Linolenic acid (ALA) is a precursor to EPA and DHA; however, its conversion in humans is thought to be inefficient. ALA can also undergo free radical oxidation, forming compounds known as F(1)-phytoprostanes, which are found in all plants and are in high concentrations in plant pollens. In this study, we examined the effect of ALA supplementation on plasma and urine F(1)-phytoprostane and F(2)-isoprostane concentrations in men. Thirty-six nonsmoking men, aged 20-65 y, were recruited from the general population and randomly allocated to consume 9 g/d of either flaxseed oil (62% ALA, 5.4 g/d) or olive oil (placebo) for 4 wk in a parallel design. At baseline and after 4 wk of supplementation, blood samples and a 24-h urine sample were collected for measurement of plasma and urinary F(1)-phytoprostanes and F(2)-isoprostanes and plasma fatty acids. Compared with the olive oil group, plasma phospholipid ALA was greater (P < 0.0001), as were F(1)-phytoprostanes in plasma (P = 0.049) and urine (P = 0.06) in the flaxseed oil group after 4 wk supplementation. Flaxseed oil did not affect plasma or urinary F(2)-isoprostanes. The greater plasma F(1)-phytoprostane concentration in the flaxseed oil group most likely resulted from the increased plasma concentration of the ALA substrate and/or the F(1)-phytoprostane content of the flaxseed oil. Future studies are needed to determine the physiological importance of increased plasma and urine F(1)-phytoprostanes and their relevance to heart disease prevention.
Barden
Anne E
AE
University of Western Australia, School of Medicine and Pharmacology, Cardiovascular Research Center, Royal Perth Hospital, 6001, Western Australia, Australia. anne.barden@uwa.edu.au
Croft
Kevin D
KD
Durand
Thierry
T
Guy
Alexandre
A
Mueller
Martin J
MJ
Mori
Trevor A
TA
D000328:Adult; D000368:Aged; D019587:Dietary Supplements; D005231:Fatty Acids, Unsaturated / Q000097:blood* / Q000652:urine; D006801:Humans; D008043:Linseed Oil / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D010938:Plant Oils / Q000494:pharmacology; D055815:Young Adult; D017962:alpha-Linolenic Acid / Q000494:pharmacology*
D005231:Fatty Acids, Unsaturated; D000069463:Olive Oil; D010938:Plant Oils; D017962:alpha-Linolenic Acid; D008043:Linseed Oil