Researchers from the University of Catania report that supplementation reduced LDL oxidation by 15 units per litre of blood, compared to a 3 U/L reduction in the placebo group.
The results suggest a positive role for L-carnitine supplements in type 2 diabetics. The condition is associated with higher levels of oxidative stress correlated to LDL levels. An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
In the US, there are over 20 million people with diabetes, equal to seven per cent of the population.
L-Carnitine, a vitamin-like nutrient, occurs naturally in the human body and is essential for turning fat into energy. It is frequently used as a dietary supplement by physically active people to help with post-exercise recovery.
The market for L-carnitine is reportedly dominated by Lonza. The company claims to be the world's largest manufacturer of the compound, and has said that extensive scientific research shows the supplement promotes cardiovascular health and that other studies suggest the nutrient may be useful in weight management.
The researchers, led by Mariano Malaguarnera, recruited 81 people with type-2 diabetes, and randomly assigned the to one of two groups. The first group received a daily L-carnitine supplement (2 grams), while the other group received a placebo.
After three months of interventions, the researchers found that people in the L-carnitine group had significant improvements in levels of oxidised LDL, compared to placebo. Indeed, levels dropped by 15 U/L, compared to only 3 U/L in the placebo group.
Moreover, LDL levels decreased by 0.45 mmol/L in the L-carnitine group, compared to only 0.16 mmol/L in the placebo group, while improvements in triglyceride levels were also observed (a decrease of 1.02 versus 0.09 mmol/L in the L-carnitine and placebo groups, respectively).
Measures of oxidative stress in the group also showed an improvement in the L-carnitine group. Using the thiobarbituric acid-reactive substance (TBARS) assay Malaguarnera and co-workers report a decrease of 1.92 in the L-carnitine group, compared to a reduction of only 0.05 in the placebo group.
“Our study indicates that oral administration of L-carnitine reduces oxidized LDL cholesterol levels in patients with type 2 diabetes,” concluded the researchers.
The study was funded by the Ministero dell'Università e Ricerca Scientifica e Tecnologica.
Source: American Journal of Clinical NutritionJanuary 2009, Volume 89, Number 1, Pages 71-76, doi:10.3945/ajcn.2008.26251"L-Carnitine supplementation reduces oxidized LDL cholesterol in patients with diabetes"Authors: M. Malaguarnera, M. Vacante, T. Avitabile, M. Malaguarnera, L. Cammalleri, M. Motta