The Effect of A 4-Week Vegan Diet on Adipokine Levels in Healthy Male and Female Participants: A Randomized-Controlled Trial
Abstract Background Vegan diet (VD) is reported to show beneficial health effects including cardiovascular and anti-inflammatory protection, but the underlying mechanisms remain unclear. We hypothesized that adipokines, a special type of cytokine produced by the white adipose tissue with known effects on metabolism and the immune system, may contribute to the observed anti-inflammatory effects of VD. Methods A parallel group interventional trial was designed to evaluate the effect of VD compared to meat-rich diet (MD) on serum levels of two central adipokines, leptin and adiponectin. Fifty-three healthy, omnivore participants (62% female, average age 31 years and BMI 23.1 kg/m2) were randomly assigned to VD or MD for 4 weeks. Results End value comparison between VD group and MD group showed a significantly lower level of adiponectin in the MD group (11.6 vs. 15.5 µg/mL, p = 0.025) indicating a moderate effect size (Cohen’s d = 0.524). Participants’ sex affected adipokine levels requiring a separate analysis of male and female participants. Leptin was increased by MD only in male participants (p = 0.019) whereas adiponectin remained stable. Female participants in VD group showed higher adiponectin levels at the end of trial (compared to VD-baseline, p = 0.023, as well as compared to MD group, p = 0.015). The end concentration of adiponectin depended on diet in female participants (p = 0.010). Conclusion The results of our trial suggest that plasma concentration of leptin and adiponectin do not explain the immunomodulatory potential of VD in healthy participants, but it appears that diet modifies adipokine levels in a sex-specific manner.Trial registration: German Clinical Trial register (DRKS00011963), registered 30 March 2017, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011963.