Science Update

New Review Investigates the Effects of Carnitine Supplementation on Metabolic Syndrome

Metabolic syndrome and insulin resistance are a significant health-care problem in the United States. Type 2 diabetes affects more than 300 million people.

Insulin resistance is preventable and reversible through lifestyle changes, proper nutrition, supplements, exercise, and stress management. Weight loss and exercise are the best treatments for restoring the body's ability to respond to insulin.

 A previous review demonstrated that L-carnitine supplementation reduced body weight, body mass index, and fat mass.

 According to a new review published last week in Nutrients, researchers investigated the effects of carnitine supplementation on specific biomarkers of metabolic syndrome.

This review consisted of nine randomized, placebo-controlled trials including 508 patients. Clinical trials were included if they had at least one of the following assessments: waist circumference, blood pressure, fasting glucose levels, triglycerides, or high-density lipoprotein (HDL) cholesterol levels. The studies ranged in size from 18 to 81 individuals for a duration between 8 to 24 weeks. The most common study duration was 12 weeks and the average age of the patient was 41 years old. Six of the studies used L-carnitine as the only treatment, one used L-carnitine along with calorie restriction, and two used a L-carnitine combined with calorie restriction and exercise. The daily dose of L-carnitine ranged from 750 mg to 3 grams per day, with 2 grams being the most common.

Two of the studies demonstrated changes in waist circumference. Two studies found changes in blood pressure. Five studies indicated changes in fasting glucose levels. Six studies showed changes in triglycerides. Five studies were shown to have changes in HDL cholesterol levels. As a result, L-carnitine supplementation significantly reduced waist circumference and also systolic blood pressure. In addition, the research team found that L-carnitine supplementation at a dose of more than 1 gram per day significantly reduced fasting glucose levels and triglycerides. Also, L-carnitine supplementation increased HDL levels.

In summary, L-carnitine supplementation is correlated with a significant reduction of both waist circumference and blood pressure. A dosage between 1 and 3 grams per day should be considered to help support normal biomarkers that are related to metabolic syndrome. Other nutrients to consider include inositol, tocotrienols, lipoic acid, fish oil, magnesium, and glycine.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Choi M, Park S, Lee M. L-carnitine’s effect on the biomarkers of metabolic syndrome: a systematic review and meta-analysis of randomized controlled trials. Nutrients 2020;12(9):2795. doi:org/10.3390/nu12092795.