engleski

The effect of L-carnitine supplementation on metabolism and exercise performance in athletes

Understanding the regulatory mechanisms and metabolic pathways that provide energy for muscle work is the subject of interest of many studies, particularly in the field of sports. The appropriate intake of nutrients seeks to achieve optimum energy efficiency for maximum performance and minimal damage. L-Carnitine (L-3-hydroxy-trimethyl-aminobutanoate) is a metabolite whose role in the metabolism is mainly known. It can be synthesized endogenously or taken by food, mainly through meat and dairy products. Mediating the translocation of long chain fatty acids from cytosol to mitochondria, carnitine plays a crucial role in supplying fats as a fuel for oxidation processes aimed to provide energy for cellular functions, including muscle contraction. Also, as a part of acyl carnitine/coenzyme A pool, it participates in the regulation of carbohydrate metabolism, as well as fatty acids synthesis. The awareness of the carnitine’s role in the oxidation of fatty acids has led to the supposition that the increased intake of carnitine can amplify the efficiency of fat utilisation and thus provide more energy for muscle contraction. At the same time, increased utilization of fats would result in a reduction of adipose tissue, and thus allow a reduction of body mass in obese subjects. In the research on the action of carnitine, which was carried out on groups of athletes, as well as on subjects with sedentary lifestyle, we found no association of increased L-carnitine intake with neither the fitness of athletes nor with the body mass reduction. Similarly, a number of studies that have been carried out have failed to demonstrate positive impact of carnitine supplementation on metabolism and sport performance in athletes. Although additional carnitine intake leads to increased concentration in blood, the resorption into muscle tissue is rather poor. A few studies have found connection of carnitine intake with the increased oxygen consumption and the reduced concentration of lactate in the blood. However, most studies have shown that carnitine supplementation has no effect on the accumulation of lactate and the use of muscle glycogen and does not improve athletic performance in healthy individuals. Taken together, the results of the available studies suggest that carnitine, though necessary, is not a limiting factor in the process of energy supply through oxidation of fatty acids.

L-carnitine, fat oxidation, athletes, body mass reduction

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