Effect of omega-3 fatty acid plus vitamin E Co-Supplementation on oxidative stress parameters: A systematic review and meta-analysis

Background & aims: The impact of combined omega-3 FAs and vitamin E supplementation on oxidative stress (OS) has been evaluated in several studies. However the results are inconsistent. Therefore, we performed a systematic review and meta-analysis to assess the role of omega-3 FAplus vitamin E on anti-oxidant and OS parameters. Methods: We searched five databases (PubMed, Embase, Web of Sciences, Scopus and the Cochrane Central Register of Controlled Trials) from inception until March 15th 2018 for RCT covering OS parameters combined with omega-3 FAs and vitamin E. The effect of omega-3 FAs plus vitamin E combination on OS factors was determined as the standardized mean difference (SMD) calculated according to DerSimonian and Laird for the random effects model. Results: Nine articles were included in our analyses, significant improvements were observed in trials supplementing with omega-3 FAs plus vitamin E vs placebo for total antioxidant capacity (TAC) (SMD=0.63, 95%CI: 0.31 to 0.95, P<0.001) and nitric oxide (NO) (SMD=0.55, 95%CI: 0.23 to 0.87, P<0.001). Significant reduction was observed for malondialdehyde (MDA) (SMD: -0.48, 95%CI: -0.68 to -0.28, P<0.001). However, the results of meta-analysis did not show a significant difference in levels of glutathione (GSH) (SMD=0.34, 95%CI: -0.07 to 0.75, P=0.10), superoxide dismutase (SOD) activity (SMD: 0.07, 95% CI: -0.58 to 0.73, P=0.82) and Catalase (CAT) activity (SMD: 0.74, 95% CI: -0.30 to 1.79, P=0.16). Conclusion: Co-supplementation with omega-3 FAs and vitamin E increases the levels of NO and TAC, while MDA levels decrease compared to placebo. However, the results showed no significant alterations on GSH concentrations, CAT, and SOD activities. (C) 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.