Impact of low-carbohydrate diet on serum levels of leptin and adiponectin levels: a systematic review and meta-analysis in adult

Abstract

Background Various studies have evaluated the effects of low-carbohydrate diet (LCD) on serum concentrations of adipokines. Although the association between LCD and serum levels of leptin and adiponectin has been studied extensively, the results were not consistent. Objective The purpose of this study was to systematically evaluate the effect of LCD on serum levels of leptin and adiponectin. Design Electronic databases were retrieved in PubMed, Embase, Scopus and Web of Science to search relevant publications. Pooled standard mean difference (SMD) with 95 confidence interval (CI) was calculated by the random-effect model. Cochrane Q test and I-2 statistic were used to test heterogeneity. Subgroup analysis and meta-regression were applied to assess possible sources of heterogeneity. Results A total of thirty-five articles were included in final analysis. Meta-analysis results revealed no statistical association between LCD and adiponectin concentration (WMD: 0.32 ng/ml, 95 CI: - 0.02, 0.66, p=0.062). Subgroup analysis showed that LCD increased adiponectin concentration in subjects under 45 years old and in studies with long term duration intervention. Also, did not observe a significant effect from the LCD on serum concentration of leptin (WMD: - 0.77 ng/ml, 95 CI: -3.15, 1.61, P=0.409). Subgroup analysis did not show any new information. The results of this study did not support the evidence for the positive effects of LCD on serum leptin and adiponectin levels.