Effect of alpha-lipoic acid combined with creatine monohydrate on human skeletal muscle creatine and phosphagen concentration.
Burke DG, Chilibeck PD, Parise G, Tarnopolsky MA, Candow DG.
Department of Human Kinetics, St. Francis Xavier University, Antigonish, Nova Scotia, Canada B2G 2W5.
Alpha-lipoic acid has been found to enhance glucose uptake into skeletal muscle in animal models. Studies have also found that the co-ingestion of carbohydrate along with creatine increases muscle creatine uptake by a process related to insulin-stimulated glucose disposal. The purpose of this study was to determine the effect of alpha-lipoic acid on human skeletal muscle creatine uptake by directly measuring intramuscular concentrations of creatine, phosphocreatine, and adenosine triphosphate when creatine monohydrate was co-ingested with alpha-lipoic acid. Muscle biopsies were acquired from the vastus lateralis m. of 16 male subjects (18-32 y) before and after the experimental intervention. After the initial biopsy, subjects ingested 20 g x d(-1) of creatine monohydrate, 20 g x d(-1) of creatine monohydrate + 100 g x d(-1) of sucrose, or 20 g x d(-1) of creatine monohydrate + 100 g x d(-1) of sucrose + 1000 mg x d(-1) of alpha-lipoic acid for 5 days. Subjects refrained from exercise and consumed the same balanced diet for 7 days. Body weight increased by 2.1% following the nutritional intervention, with no differences between the groups. There was a significant increase in total creatine concentration following creatine supplementation, with the group ingesting alpha-lipoic acid showing a significantly greater increase (p < .05) in phosphocreatine (87.6 --> 106.2 mmol x kg(-1) dry mass [dm]) and total creatine (137.8 --> 156.8 mmol x kg(-1) dm). These findings indicate that co-ingestion of alpha-lipoic acid with creatine and a small amount of sucrose can enhance muscle total creatine content as compared to the ingestion of creatine and sucrose or creatine alone.
