Can flaxseed supplementation affect circulating adipokines in adults? An updated systematic review and meta-analysis of randomized controlled trials

Abstract

IntroductionThe findings of randomized controlled trials (RCTs) regarding the effect of flaxseed on adipokine concentrations are conflicting. Therefore, the present meta-analysis was conducted to provide definite and conclusive results.MethodsSystematically, Scopus, Embase, PubMed, Web of Science databases, and Google Scholar were searched for relevant literature published up to December 2022. Based on random-effect models, standard mean differences (SMDs) were calculated for net changes in adipokine concentrations.ResultsOverall, 13 RCTs (15 arms) were eligible to be included. The results indicated that leptin was significantly reduced after the intervention with flaxseed supplement (SMD = −0.69, 95% CI: −1.37, −0.01; p = 0.048; I2 = 92.0%, p < 0.001). In addition, flaxseed supplements had no considerable effect on plasma adiponectin (SMD = 0.52, 95% CI: −0.20, 1.25, p = 0.159; I2 = 92.0%, p < 0.001).DiscussionFlaxseed significantly improves leptin but does not affect adiponectin concentrations. Additional future well-designed trials are required to further assess the potential benefits of flaxseed on adipokines in humans.