Original Article

European Journal of Clinical Nutrition (2006) 60, 386–392. doi:10.1038/sj.ejcn.1602328; published online 9 November 2005

Effects of docosahexaenoic acid supplementation on blood lipids, estrogen metabolism, and in vivo oxidative stress in postmenopausal vegetarian women

Guarantor: WH Wu.

Contributors: WHW designed the study, contributed to method development, data interpretation and preparation of the manuscript. SCL initiated the study, obtained a research grant for the study and was responsible for all stages of the study. TFW was responsible for biochemical and statistical analyses and taking care of the study subjects. HJJ and TAW were the gynecologists involved in subject recruitment, sample processing and advised on protocol design. All authors contributed to the writing of the manuscript.

W H Wu1, S C Lu2, T F Wang1, H J Jou3 and T A Wang4

  1. 1Graduate Program of Nutrition, Department of Human Development and Family Studies, National Taiwan Normal University, Taipei, Taiwan
  2. 2Department of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
  3. 3Department of Obstetrics and Gynecology, Taiwan Adventist Hospital, Taipei, Taiwan
  4. 4Department of Obstetrics and Gynecology, Taipei City Hospital Yangming Branch, Taipei, Taiwan

Correspondence: Professor WH Wu, Graduate Program of Nutrition, Department of Human Development and Family Studies, National Taiwan Normal University, Taipei 106, Taiwan. E-mail: t10005@cc.ntnu.edu.tw

Received 27 October 2004; Revised 16 August 2005; Accepted 14 September 2005; Published online 9 November 2005.

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Abstract

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-OHE1) to 16alpha-hydroxyestrone (16alpha-OHE1).

Objective:

 

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

Design:

 

Single-blind, randomized, placebo-controlled trial.

Interventions:

 

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.

Main outcome measures:

 

Plasma lipids, urinary 2-OHE1 and 16alpha-OHE1, urinary F2-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 F2-isoprostanes, 2-OHE1, 16alpha-OHE1 and ratio of 2-OHE1 to 16alpha-OHE1 as compared to corn oil.

Conclusion:

 

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.

Sponsorship:

 

A grant (# DOH89-TD-1062) from Department of Health, Executive Yuan, Taiwan.

Keywords:

DHA, algae oil, hydroxyestrone, blood lipids, oxidative stress, postmenopausal vegetarian women

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