The effects of supplementation with L-carnitine on apolipoproteins: A systematic review and meta-analysis of randomized trials

Randomized controlled trials (RCTs) have reported that L-carnitin may change serum apolipoproteins. However, the results of RCTs are contradictory. Our objective was to conduct a systematic review and meta-analysis to summarize earlier RCTs on the effects of L-carnitine supplementation on apolipoproteins B100 and AI. ISI web of science, Ovid, PubMed/Medline, Scopus, and Google Scholar were searched from inception to January 2019 using relevant keywords. Treatment effects were considered as weighted mean difference (MD) and the corresponding 95% confidence interval in concentrations of serum apolipoproteins. Random-effects model (Dersimonian-Liard) was used to estimate the overall summary effect. This meta-analysis was performed on fourteen trials. Our results indicated that L-carnitine supplementation has a non-significant effect on Apo B100 (mean difference (MD): 1.820 mg/dl; 95% CI: - 3.367 to 7.006, p = 0.492) and Apo AI (MD: - 0.119 mg/dl; 95% CI: -4.425 to 4.186, p = 0.957). We also found body mass index, L-carnitine dosage; health condition and intervention duration could change the results. We conclude that L-carnitine does not change Apo B100 and Apo AI concentration. Further trials with sufficient sample size are needed to confirm these findings.