L-carnitine Supplementation Significantly Improves Lipid Profiles

by | Oct 19, 2023 | 2023, Blood Lipids, Carnitine

Written by Taylor Woosley, Staff Writer. Findings of this umbrella meta-analysis of 13 meta-analyses shows that L-carnitine supplementation significantly decreased total cholesterol (p < 0.001), triglycerides (p < 0.001), and LDL-C (p < 0.001) levels, while also increasing HDL-C levels (p = 0.005). 

blood lipidsCardiovascular disease (CVD) is the number one cause of mortality globally1. Atherosclerosis, one of the main risk factors of CVD, consists of the initial endothelial cell injury followed by lipoprotein deposition, inflammatory reaction, and smooth muscle cell cap formation2. Dyslipidemia plays a fundamental role in CVD development and clinical studies have established a causal association between elevated levels of LDL-C and an increased risk of atherosclerotic CVD3.

Carnitine is a dipeptide which is an essential factor for the membrane transport of acyl-coenzyme A4. L-carnitine, the active form of dietary carnitine, also plays an important role in the regulation of metabolic pathways involved in skeletal muscle protein balance5. Emerging research has shown L-carnitine as an effective target for CVD prevention and treatment because it has an important role in the oxidation of fatty acids and cardiac energy metabolism6.

Musazadeh et al. conducted an umbrella meta-analysis to analyze accurate and deterministic data regarding supplementation with L-carnitine on lipid profiles including triglycerides (TG), total cholesterol (TC), LDL-C, and HDL-C levels. Study inclusion consisted of meta-analyses of randomized controlled trials (RCTs), with subjects aged 18 years or older, using L-carnitine as the intervention, with a control or placebo group, a duration of follow-up of ≥2 weeks, and outcomes including lipid profiles and changes in TG, HDL-C, LDL-C, and TC.

To assess heterogeneity of the meta-analysis, the Cochran-Q test and I2 index were utilized. Subgroup analyses based on study duration, L-carnitine dose, sample size, age, and health status were conducted to identify potential sources of heterogeneity. 13 meta-analyses consisting of 51, 54, 58, and 59 separate clinical trials for LDL-C, HDL-C, TC and TG, respectively, were included in the final analysis. Participant age range among studies was from 26 to 53 years and L-carnitine dosage ranged from 0.54 g/day to 2.4 g/day, with a study duration of 14 to 25 weeks. Significant findings of the umbrella meta-analysis are as follows:

  • Total cholesterol levels were significantly lowered after L-carnitine supplementation (p = 0.002), with a significant between-study heterogeneity (I2 = 87.1%, p < 0.001).
  • Participants supplementing with L-carnitine had significantly decreased levels of TG (p < 0.001). Significant between-study heterogeneity was noted (p < 0.001).
  • Data from 4 meta-analyses shows a significant reduction in LDL-C levels after L-carnitine supplementation (p < 0.001). A significant degree of heterogeneity was noted (p < 0.001).
  • Supplementation with L-carnitine significantly increased HDL-C levels (p = 0.005), with a high degree of heterogeneity detected (p < 0.001).

Results of the umbrella meta-analysis of 13 meta-analyses shows that L-carnitine supplementation significantly decreased TC, TG, and LDL-C levels. Additionally, an increase in HDL-C levels were noted. Further research on L-carnitine use should continue to explore the beneficial effects of L-carnitine on lipid profiles. Study limitations include the high heterogeneity of study characteristics which makes it difficult to reach any strong conclusions.

Source: Musazadeh, Vali, Hanie Alinejad, Niloofar Kouhi Esfahani, Zeynab Kavyani, Majid Keramati, Neda Roshanravan, Erfan Mosharkesh, and Parvin Dehghan. “The effect of L-carnitine supplementation on lipid profile in adults: an umbrella meta-analysis on interventional meta-analyses.” Frontiers in Nutrition 10 (2023).

© 2023 Musazadeh, Alinejad, Esfahani, Kavyani,Keramati, Roshanravan, Mosharkesh and Dehghan. This is an open-access article distributed under the terms of the Creative
Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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Posted October 19, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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