Effects of docosahexaenoic acid supplementation on blood lipids, estrogen metabolism, and in vivo oxidative stress in postmenopausal vegetarian women.
BACKGROUND
Vegetarians are generally deficient in long-chain n-3 fatty acids. Long-chain n-3 fatty acids have a beneficial effect on plasma lipid levels, and some studies showed that they had breast cancer suppression effect. One of the biomarkers of breast cancer risk is the ratio of urinary 2-hydroxyestrone (2-OHE(1)) to 16alpha-hydroxyestrone (16alpha-OHE(1)).


OBJECTIVE
To investigate the effect of docosahexaenoic acid (DHA, 22:6n-3) supplementation on blood lipids, estrogen metabolism and oxidative stress in vegetarians.


METHODS
Single-blind, randomized, placebo-controlled trial.


METHODS
Twenty-seven postmenopausal vegetarian women were recruited. After a 2-week run-in period with 6 g placebo corn oil, the subjects were subsequently randomized to receive either 6 g corn oil (n=13) or 6 g DHA-rich algae oil (2.14 g of DHA/day) (n=14) for 6 weeks. Two subjects in corn oil group withdrew before completion.


METHODS
Plasma lipids, urinary 2-OHE(1) and 16alpha-OHE(1), urinary F(2)-isoprostanes and plasma alpha-tocopherol.


RESULTS
Plasma LDL-DHA and EPA level increased significantly by DHA supplementation. DHA decreased plasma cholesterol (C) levels (P=0.04), but did not influence the levels of plasma TG, LDL-C and HDL-C, alpha-tocopherol, urinary F(2)-isoprostanes, 2-OHE(1), 16alpha-OHE(1) and ratio of 2-OHE(1) to 16alpha-OHE(1) as compared to corn oil.


CONCLUSIONS
DHA supplementation at a dose of 2.14 g/day for 42 days decreases plasma cholesterol but neither does it show beneficial effects on estrogen metabolism, nor does it induce deleterious effects on the observed in vivo antioxidant or oxidative stress marker in postmenopausal vegetarian women.


BACKGROUND
A grant (# DOH89-TD-1062) from Department of Health, Executive Yuan, Taiwan.
Wu
W H
WH
Graduate Program of Nutrition, Department of Human Development and Family Studies, National Taiwan Normal University, Taipei, Taiwan. t10005@cc.ntnu.edu.tw
Lu
S C
SC
Wang
T F
TF
Jou
H J
HJ
Wang
T A
TA
D015415:Biomarkers / Q000097:blood / Q000652:urine; D014676:Diet, Vegetarian; D019587:Dietary Supplements; D004281:Docosahexaenoic Acids / Q000008:administration & dosage* / Q000378:metabolism*; D004967:Estrogens / Q000378:metabolism* / Q000652:urine; D056890:Eukaryota / Q000737:chemistry; D028441:F2-Isoprostanes / Q000652:urine; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000652:urine; D008055:Lipids / Q000097:blood*; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D017698:Postmenopause; D016037:Single-Blind Method; D024502:alpha-Tocopherol / Q000097:blood
D015415:Biomarkers; D004967:Estrogens; D028441:F2-Isoprostanes; D006894:Hydroxyestrones; D008055:Lipids; D004281:Docosahexaenoic Acids; D024502:alpha-Tocopherol; C024980:2-hydroxyestrone