Effect of omega-3 fatty acid supplementation on inflammation, muscle damage and exercise performance in athletes : a systematic review and meta-analysis

Abstract

Background: Large volumes of unaccustomed, intense exercise in athletes cause increased muscle damage, inflammation and suppression of the immune system resulting in delayed exercise recovery, overtraining syndrome, and compromised exercise performance. Available evidence suggests that omega-3 (n-3) polyunsaturated fatty acids (PUFAs) may alter the exercise-induced inflammatory response and have immunomodulatory effects in athletes and active individuals, however the evidence regarding this topic is contradicting. Therefore, the aim of this Masters study was to perform a systematic review and meta-analysis (where possible) of the literature regarding the effect of n-3 PUFA supplementation on exercise-induced inflammation, muscle damage and exercise performance in athletes. Methods: Seven electronic databases were searched and 18 randomised controlled trials were included for analysis. Meta-analytical synthesis was performed using a random effect analysis to calculate the effect size of n-3 PUFA supplementation on markers of inflammation (Tumor Necrosis Factor [TNF]-α, Interleukin 2 [IL-2], -6 [IL-6], -4 [IL-4], -10 [IL-10] and C-reactive protein [CRP]), muscle damage (creatine kinase [CK]) and exercise performance (time trial time and time to exhaustion). A sensitivity analysis was done excluding one study at a time. Heterogeneity was evaluated by the I-square index and Cochrane’s Q test. Results: A suggestive trend for a statistically significant beneficial effect of n-3 PUFA supplementation on anti-inflammatory cytokine IL-10 (SMD = 0.74, 95% CI: -0.08 to 1.56; P = 0.075) was observed. Moreover, this study also observed a suggestive trend for a statistically significant reduction of the pro-inflammatory marker CRP (SMD = -2.03, 95% CI: -4.31 to 0.25, P = 0.081). However, we observed no effect of n-3 PUFA supplementation on inflammatory markers TNF-α, IL-2, IL-4, IL-6, muscle damage marker CK or exercise performance measurements. Conclusion: Although n-3 PUFA supplementation demonstrated no beneficial effects on exercise performance and some inflammatory markers (TNF-α, IL-2 and IL-4), the potential increase in the anti-inflammatory cytokine IL-10 as well as the reduction of CRP concentrations suggest that n-3 supplementation potentially enhances aspects of the immune system and improve exercise recovery