Combination of aerobic exercise and an arginine, alanine, and phenylalanine mixture increases fat mobilization and ketone body synthesis

During exercise, blood levels of several hormones increase acutely. We hypothesized that consumption of a specific combination of amino acids (arginine, alanine, and phenylalanine; A-mix) may be involved in secretion of glucagon, and when combined with exercise may promote fat catabolism. Ten healthy male volunteers were randomized in a crossover studyto ingesteither A-mix (3 g/dose) or placebo (3 g of dextrin/dose). Thirty minutes after ingesting, each condition subsequentlyperformed workload trials on a cycle ergometer at 50% of maximal oxygen consumption for 1 h. After oral intake of A-mix, the concentrations of plasma ketone bodiesand adrenalin during and post-exercise were significantly increased. The area underthe curvefor glycerol and glucagonwas significantly increased in the post-exercise by A-mix administration. These results suggest that pre-exercise ingestionof A-mix causes a shift of energy source from carbohydrate to fat combustion by increasing secretion of adrenalin and glucagon.