The combined effects of omega-3 polyunsaturated fatty acid supplementation and exercise training on body composition and cardiometabolic health in adults: a systematic review and meta-analysis.

Introduction: We performed a systematic review and meta-analysis to investigate the effects of combining omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplementation with exercise training, as compared to exercise training alone, on body composition measures including body weight, body mass index (BMI), fat mass, body fat percentage, and lean body mass. Additionally, we determined the effects on cardiometabolic health outcomes including lipid profiles, blood pressure, glycemic markers, and inflammatory markers.

Method: Three primary electronic databases including PubMed, Web of Science, and Scopus were searched from inception to April 5, 2023 to identify original articles comparing n-3 PUFA supplementation plus exercise training versus exercise training alone, that investigated at least one of the following outcomes: fat mass, body fat percentage, lean body mass, triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), systolic (SBP) and diastolic (DBP) blood pressures, fasting glucose and insulin, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Standardized mean differences (SMD) or weighted mean differences (WMD), and 95% confidence intervals (CIs) were calculated using random-effects models.

Results: A total of 21 studies involving 673 participants with BMIs ranging from 24-37 kg.m2 and ages ranging from 30-70 years were included in the meta-analysis. Overall, the results indicated that as compared with exercise training alone, adding omega-3 supplementation to exercise training decreased fat mass [WMD: -1.05 kg (95% CI: -1.88 to -0.22), p = 0.01], TG [WMD: -0.10 mmol/L (95% CI: -0.19 to -0.02)], SBP [WMD: -4.09 mmHg (95% CI: -7.79 to -2.16), p = 0.03], DBP [WMD: -4.26 mmHg (95% CI: -6.46 to -2.07), p = 0.001], and TNF-α [SMD: -0.35 (95% CI: -0.70 to -0.00), p = 0.04], and increased LDL [WMD: 0.14 mmol/L (95% CI: 0.02 to 0.26), p = 0.01] and lower-body muscular strength [SMD: 0.42 (95% CI: 0.01 to 0.84), p = 0.04]. However, omega-3 supplementation with exercise training had no additional effects compared with training alone, for other body composition or cardiometabolic outcomes.

Conclusion: This systematic review and meta-analyses suggestes that adding omega-3 supplementation to exercise training may augment some effects of exercise training on body composition and cardiometabolic health in adults, although such effects appear to be modest.