Effect of omega-3 fatty acids supplementation on endothelial function: A meta-analysis of randomized controlled trials

January 1, 2012 Human Health and Nutrition Data 0 Comments

Effect of omega-3 fatty acids supplementation on endothelial function: A meta-analysis of randomized controlled trials

Year: 2012
Authors: Wang, Q. Liang, X. Wang, L. Lu, X. Huang, J. Cao, J. Li, H. Gu, D.
Publication Name: Atherosclerosis
Publication Details: Volume 221; Pages 536 – 543.


Objective: Inverse association was reported between omega 3 fatty acids (FAs) supplementation and the risk of cardiovascular disease. Identifying the effect of omega 3 FAs on endothelial function may contribute to explain the association. We conducted a meta analysis to assess the effect of omega-3 FAs supplementation on endothelial function, as measured by flow mediated dilation (FMD) and endothelium-independent vasodilation (EIV). Methods: Randomized placebo-controlled trials (RCTs) were identified from the databases of PubMed, EMBASE and Cochrane library by two investigators and the pooled effects were measured by weighted mean difference (WMD), together with 95% confidence intervals (CIs). Subgroup and meta-regression analyses were used to explore the source of between-study heterogeneity. Results: Totally 16 eligible studies involving 901 participants were finally included in meta-analysis. Compared with placebo, omega-3 FAs supplementation significantly increased FMD by 2.30% (95% CI:0.89 to 3.72%, P = 0.001), at a dose ranging from 0.45 to 4.5 g/d over a median of 56 days. Subgroup analyses suggested that the effect of omega 3 FAs on FMD might be modified by the health status of the participants or the dose of supplementation. Sensitivity analyses indicated that the protective effect of omega-3 on endothelial function was robust. No significant change in EIV was observed after omega-3 FAs supplementation (WMD: 0.57%; 95% CI:−0.88 to 2.01%; P = 0.442). Conclusion: Supplementation of omega-3 fatty acids significantly improves the endothelial function without affecting endothelium-independent dilation. (Authors abstract)
Data from large-scale prospective studies and meta-analysis have provided evidence that dietary intake of omega-3 fatty acids (FAs), including alpha-linolenic acid (ALA), eicosapentaenoic (EPA) and docosahexaenoic (DHA), has beneficial effects on various cardiac disorders, including cardiovascular diseases (CVD) and sudden death. The cardioprotective effect might be partly explained by their antiatherosclerosis role in improving endothelial dysfunction. This study provides a systematic review of the published randomized controlled trials that measured endothelial function by FMD and EIV to explore effects of omega 3 FAs on endothelial function. Data from 16 trials showed that omega 3 FAs supplementation significantly improved endothelial function, at a dose ranging from 0.45 to 4.5 g/d over a median of 56 days. Significantly increased FMD by omega 3 were observed for individual with cardiovascular disease or its risk factor profiles at baseline, compared with health individuals. No significant changes in EIV after omega 3 FAs supplementation were observed at a dose ranging from 0.45 to 4.7 g/d. The mechanism underlying the protective effect of omega 3 on endothelial function has not been identified. It might be mediated by incorporation into cellular membranes resulting in a reduction of omega 6 polyunsaturated fatty acids (PUFAs). In other studies, internal brachial artery diameter was significantly improved after treatment with omega 3 FAs in subjects with hypercholesterolemia without affecting endothelium-independent dilation. A recent clinical trial including 367 participants documented intakes of low dose of omega 3 fatty acids (≤1.8 g/d) did not improve endothelial function. One explanation from the author was that omega 3 intake might have no added cardiovascular health benefit in healthy individuals. Markers of endothelial function might be improved by omega 3 supplementation for participants with CVDs or cardiovascular diseases risk factors. In the general, low to moderate intake of omega 3 FAs has shown dose dependent effect markers of endothelial function and the high dose effect of omega 3 FAs remains inconsistent.  Although positive association was identified between omega 3 FAs and endothelial function, the evidence for a clinical efficacy is not strong enough to make final recommendations concerning to a specific doses or the durations of intakes for different populations. Future well designed studies are warranted to identify the target population for omega 3 FAs supplementation and determine the optimal dose. (Editors abstract)

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