Metabolismo de carnosina, suplementação de β-alanina e desempenho físico: uma atualização – PARTE II

• Published in: Revista brasileira de nutrição esportiva 2015-09, Vol.9 (52), p.379-398
• Main Authors: Gualano, Bruno, Artioli, Guilherme Giannini, Freitas, Paola, Painelli, Vitor S, Saunders, Bryan
• Format: Article
• Language: Portuguese
• Subjects: alanina; Beta; beta-alanina; Carnosina; Desempenho atlético; Suplementos dietéticos
• ISSN: 1981-9927; 1981-9927

Carnosine metabolism, β-alanine supplementation and performance: an update - Part IIThere are several factors that can lead to muscle fatigue during high-intensity exercise. Among them, the accumulation of H+ ions, leading to a decrease in intramuscular pH, is considered a major cause of fatigue during this type of exercise. Thus, intramuscular buffering represents the first line of defense against the accumulation of these ions. Nutritional strategies aiming to optimize the action of such defenses have received considerable attention in the field of sports nutrition in recent times, with beta-alanine a particular focus in the last years. Supplementation with this non-essential, non-proteogenic amino acid induces an increase in muscle carnosine concentration. Carnosine is a cytoplasmic dipeptide whose most attributable function is acting as a buffer. Therefore, many studies have been devoted to investigate the effects of beta-alanine supplementation on high-intensity exercise performance and capacity; the ergogenic efficacy of beta-alanine has been investigated in different populations (sedentary, physically active, athletes and elderly) and in different exercise protocols (incremental, continuous anaerobic, intermittent anaerobic, sport-specific). Furthermore it is combination with physical training and other nutritional strategies to improve exercise has also received special focus of research. In light of the intense and growing interest in beta-alanine supplementation, this review aims to narratively describe such studies, emphasizing the implication of the findings for the areas of sports nutrition and exercise physiology. Diversos são os fatores que podem levar à fadiga muscular durante os exercícios de alta intensidade e curta duração. Dentre eles, o acúmulo de íons H+, levando a uma queda do pH intramuscular, é apontado como uma das principais causas da fadiga durante este tipo de exercício. Sendo assim, as defesas tamponantes intramusculares representam a primeira linha de defesa contra o acúmulo destes íons. Estratégias nutricionais visando otimizar a ação de tais defesas tem recebido especial atenção no campo da nutrição esportiva. Nesse sentido, a suplementação de beta-alanina é a que mais tem se destacado em anos recentes. A suplementação com este aminoácido não essencial e não proteogênico induz um aumento das concentrações musculares de carnosina. A carnosina, por sua vez, é um dipeptídeo citoplasmático cuja função mais bem atribuída é a de