Effects of L-carnitine supplementation on oxidative and metabolic status in patients with type 2 diabetes mellitus: A randomized, double-blind, clinical trial

Introduction: L -Carnitine is a substance produced from endogenous synthesis and dietary sources. This amino acid has antioxidant properties by reducing the effects of oxidative stress. The purpose of this study was to investigate the effects of L -carnitine supplementation on oxidative and metabolic status in patients with Type 2 diabetes mellitus (T2DM). Method: This was a randomized, double-blind, placebo-controlled clinical trial performed on seventy patients with T2DM. The participants were randomly assigned to an L -carnitine group (LG) or a placebo group (PG) to receive either L -carnitine or placebo (1000 mg/day, orally) for 12 weeks. The serum concentration of homocysteine (Hcy), fasting blood glucose (FBG), lipid profile, total antioxidant capacity (TAC) and anthropometric indices were measured at the beginning and the end of the study. Results: Sixty-four patients completed the study (32 in each group). The results revealed that intake of L -carnitine lead to a significant increase in the mean changes of TAC (0.02 0.01 vs.-0.02 +/- 0.01 mmol/l: P = 0.017) and skeletal muscle mass (SSM) (0.26 +/- 0.19 vs.-0.46 +/- 0.29 kg: P = 0.046) in the LG compared to the PG. These changes were not significant for Hcy, FBG, lipid profile and other anthropometric indices in the LG compared to the PG group (P > 0.05). Conclusion: Supplementation with daily 1000 mg L -carnitine for 12 weeks can lead to improved TAC and SSM without any significant changes in the level of Hcy, lipid profile, FBG and anthropometric indices. Future studies are warranted with long-term follow-up to confirm effectiveness of this supplementation on cardiovascular disease.