Aspartate and its ergogenic potential.

Since the discovery of the Krebs cycle, many experiments have tried to supplement this metabolic pathway with different intermediates in order to increase exercise performance. Since the first observations of Labor-it on aspartate and exercise in 1957, moi-e than 20 studies were published on the effect of aspartate on exercise capacity in man and various animal species. The results of these studies are guile equivocal. Many potential mechanisms suggested for the potential ergogenic effect of aspartate rr ere also considered in these studies. A lower ammoniemia level during exercise was one effect attributed to aspartate administration. The involvement of aspartate in the urea cycle is another biologically plausible mechanism that could accelerate ammonia removal and as a consequence a decrease of the blood ammonia level. The involvement of aspartate as an amphibolic intermediate in the Krebs cycle should also to be considered. However, the suggested effects of aspartate on glycogen sparing and on a higher free fatty acids oxidation do not find support iii the literature. Globally, studies with negative findings on endurance exercise were found in equal quantity to studies with positive results of aspartate on performance or its factors. In studies where an increase of endurance was observed in man, its magnitude was nor related to the importance of the dosage, suggesting the absence of a biologic gradient. The analysis of experiments in the rat is less favorable to arl increased endurance than results obtained in human studies. Studies on rile effect of aspartate on ammonia level and performance during resistance exercise unanimously reported negative findings. This lack of effect could be lire result of the difficulty for aspartate to access the ce ii compartment and the mitochondria in the skeletal muscle (DeHaan et al, 1985; Nakahara et al, 1964). To resolve the issue of the potential effect of aspartate an endurance performance, further research is needed, particularly regarding the effect of aspartate used in combinations. Other substances and nutritional procedures (carbohydrates and lipid loadings) used to decrease ammoniemia (monosodium glutamate, lactulose, sodium hydroxybutyrate, citrulline and sodium benzoate) are also briefly reviewed in this paper.