The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trials

Hadis Fathizadeh; Alireza Milajerdi; Željko Reiner; Fariba Kolahdooz; Zatollah Asemi

doi:10.17179/excli2019-1447

The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trials

EXCLI J. 2019 Aug 19:18:631-643. doi: 10.17179/excli2019-1447. eCollection 2019.

Authors

Hadis Fathizadeh¹, Alireza Milajerdi², Željko Reiner³, Fariba Kolahdooz⁴, Zatollah Asemi⁵

Affiliations

¹ Department of Microbiology, Kashan University of Medical Sciences, Kashan, Iran.
² Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
³ Department of Internal Medicine, University Hospital Centre Zagreb, School of Medicine, University of Zagreb, Zagreb, Croatia.
⁴ Indigenous and Global Health Research, Department of Medicine, University of Alberta, Edmonton, Canada.
⁵ Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran.

Abstract

The findings of trials investigating the effect of L-carnitine administration on glycemic control are controversial. This meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of L-carnitine intake on glycemic control. Two authors independently searched electronic databases including MEDLINE, EMBASE, Cochrane Library, Web of Science, PubMed and Google scholar from 1990 until February 2019, in order to find relevant RCTs. 37 studies with 44 effect sizes met the inclusion criteria and were eligible for the meta-analysis. L-carnitine supplementation resulted in a significant reduction in fasting plasma glucose (FPG) (WMD: -4.57; 95 % CI: -6.88, -2.25), insulin (WMD: -1.21; 95 % CI: -1.85, -0.57), homeostatic model assessment for insulin resistance (HOMA-IR) (WMD: -0.67; 95 % CI: -0.90, -0.44) and HbA1C concentrations (WMD: -0.30; 95 % CI: -0.47, -0.13). L-Carnitine supplementation significantly reduced FPG, insulin, HOMA-IR, and HbA1c levels.

Keywords: L-carnitine; glycemic control; insulin resistance; meta-analysis.