Efeitos da suplementação de β-alanina no desempenho do exercício físico: uma revisão sistemática com metanálise

Abstract

Beta-alanine supplementation, a short-chain amino acid, directly acts on muscle cells. These utilize beta-alanine in its non-metabolized form to synthesize carnosine. This process has proven effective as an ergogenic agent and metabolic modifier, contributing to improved performance in high-intensity exercises. The potential effects on athletic performance are based on the synthesis of carnosine, a dipeptide (β-alanyl-L-histidine), which acts as an intramuscular buffering agent during intense exercise. Muscle fatigue is a multifactorial process caused largely by the accumulation of metabolites in skeletal muscle, with ADP, Pi, and H+ being the main ones. Carnosine acts by delaying the accumulation of H+ and, consequently, enhances exercise performance. Given this, it becomes important to better understand the results of β-alanine supplementation on physical exercise performance across different sports. Thus, the main objective of this study is to assess the available literature on β-alanine supplementation in individuals engaging in high-intensity exercise to build evidence through a systematic review in accordance with PRISMA guidelines. The search was conducted in the following databases: EMBASE, PubMed/Medline, SPORTDiscus, and the CAPES platform, using the descriptors: "Beta-alanine and Exercise," combined through the Boolean operator AND. Clinical intervention studies, double-blind and placebo-controlled, that investigated the effects of Beta-alanine supplementation on physical exercise performance in a healthy adult population were applied as inclusion/exclusion criteria. All types of exercises were included, while the supplementation had to be long-term for at least four weeks. A total of 2,242 articles were found, and after the removal of duplicates (n=462), and the analysis of the articles, a selection of 13 published studies that met the criteria for this review was reached. These studies varied in exercise type, from resistance training to aerobic sports. The results suggest that β-alanine supplementation may be beneficial in physical exercise performance and improvement in fatigue; however, they indicated limited efficacy. It was observed that the positive effects were inconclusive and influenced by many variables such as population, type and duration of exercise, dosage. This review highlights the potential of beta-alanine as a supplement but also demonstrates the need for further research to better elucidate its efficacy and ideal conditions of use.