Effects of flaxseed oil supplementation on biomarkers of inflammation and oxidative stress in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

Objective This systematic review and meta-analysis of randomized controlled trials (RCTs) was performed to analyze the effects of flaxseed oil supplementation on biomarkers of inflammation and oxidative stress in patients with metabolic syndrome (MetS) and related disorders. Methods Databases including PubMed, Scopus, EMBASE, Web of Science, and Cochrane Central library were searched until January 31th, 2019. Results 14 effect sizes from 12 studies were identified eligible to be included in current meta-analysis. Flaxseed supplementation resulted in a significant reduction in interleukin 6 (IL-6) (WMD: −0.22; 95% CI: −0.43, −0.01) and malondialdehyde (MDA) (WMD: −0.17; 95% CI: −0.31, −0.03) and a significant increase in total antioxidant capacity (TAC) levels (WMD: 137.25; 95% CI: 68.04, 206.47). Flaxseed oil supplementation did not affect other biomarkers of inflammation and oxidative stress. Conclusions Overall, this meta-analysis demonstrated flaxseed oil supplementation decreased IL-6 and MDA levels, and increased TAC, but did not affect other biomarkers of inflammation and oxidative stress among patients with MetS and related disorders. This suggests that flaxseed oil supplementation may have played an indirect role in improved clinical symptoms in diseases with metabolic disorders.