Effect of L-Carnitine Supplementation on Liver Enzymes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Abstract

Possible Hepato-protective effects of L-carnitine have been reported in previous studies. Present study was conducted to systematically review the efficacy of L-carnitine supplementation on liver enzymes. The following databases were searched up to December 2018: PubMed, Scopus, ISI Web of Science, and the Cochrane library. Only randomized controlled trials (RCTs) evaluating the effects of L-carnitine supplementation on liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) were included. Pooled effect size measured using random effect model (Dersimonian-Liard). A total of 16 studies (including 1025 participants) were included in the present meta-analysis. Pooled analysis indicated that L-carnitine supplementation significantly decreased ALT (weighted mean difference (WMD): -10.729 IU/L, 95% CI: -13.787, -7.672, p<0.001; I2=95.9%), AST (WMD: -7.149 IU/L, 95% CI: -9.202, -5.096, p<0.001; I2=93.5%) and GGT (WMD: -7.395: IU/L, 95% CI: -9.171, -5.619, p<0.001; I2=80.1%). Subgroup analysis revealed that effect of L-carnitine supplementation on liver enzymes was not significant in normal weight and healthy subjects. Baseline BMI and health status were the potential source of heterogeneity. L-carnitine supplementation showed beneficial hepato-protective effects on circulating liver enzymes.