Beta-alanine (BA) is a endogenously produced amino acid with a relevant role as rate-limiting precursor to carnosine synthesis in skeletal muscle (Trexler et al., 2015). Higher levels of carnosine in muscles has been associated with improved buffering capacity, metal-ion chelation, and antioxidant scavenging (Boldyrev et al., 2013). Consequently, any strategy aimed to increase muscle carnosine content would positively influence exercise performance (Artioli et al., 2010). Although BA can be obtained through the diet (poultry and meat), its supplementation has shown to increase levels of carnosine in human skeletal muscles. The position stand of the International Society of Sports Nutrition (Trexler et al., 2015) states that BA supplementation is safe in healthy populations at recommended doses (~1.2 to 6.4 g.d-1) being the only reported side effect paraesthesia (tingling) that is avoided by the use of sustained-release formulas. BA performance enhanced effects are mainly observed in highly glycolytic tasks lasting between 1 to 4 min, but can also affect intermittent or long lasting activities. The recently published article of Saunders et al. (2017) investigated the effects of BA supplementation on muscle carnosine content, gene expression, and cycling capacity at a sustained intensity of 110% (CCT100%) of the maximal power achieved during an incremental test until volitional exhaustion. Twenty-five active males (participating in running, cycling and team sports) were supplemented with 6.4 g.d–1 of sustained release BA (n=15) or placebo (n=10) for a 24-week period. Every 4 weeks participants provided a muscle biopsy (for analyzing carnosine content and genes expression) and performed the CCT110%. Participants were asked to maintain similar levels of activity and dietary intake during the study. Supplementation involved 2 x 800 mg tablets taken 4 times per day at 3 to 4 h intervals (total 6.4 g/d). All individuals increased muscle carnosine content above baseline levels (range +17.13 to +41.32 mmol/kg-1 dry muscle). The time to reach the maximal carnosine content varied between participants and was also dependent on the initial content in muscle (5 participants needed 20 weeks and 4 of those still showed increases in excess of 6 mmol.kg-1 dry muscle from the previous time point). Maximal carnosine content was significantly correlated with performance. Furthermore, only one gene (TauT) associated with BA transport into the muscle, showed a marked decrease over the time. Authors indicate that although BA supplementation increased muscle carnosine and performance in all individuals there is a high variability between them. Furthermore, the maximal accumulation of muscle carnosine seems not occur within 24 weeks being the upper limit of muscle carnosine saturation still to be determined. The physiological adaptations induced by combining BA supplementation and training (improved delivery of BA due to the increased blood flow or a stimulation of TauT, increased expression of the BA transporter or an attenuation of its downregulation) and its effects to maximize carnosine store need to be determined.
To summarize, BA supplementation seems to be safe and beneficial for athletes involving in highly glycolytic demanding sports. Even though, a 4-week loading phase involving 4 doses of 1.6 g.d-1 following by a maintenance period using 4 daily doses of 0.8 g has been recommended (Trexler et al., 2015), the optimal protocol is still unknown. Individual doses based on body mass [~16 to 22 mg.kg-1 x 4 total daily intakes every 3 h (65 to 88 mg.kg-1 per day)] would represent a more practical approach to better adjust the supplementation protocols.
By Dr. Fernando Naclerio
Recommended reading
ARTIOLI, G. G., GUALANO, B., SMITH, A., STOUT, J. & LANCHA, A. H., JR. 2010. Role of beta-alanine supplementation on muscle carnosine and exercise performance. Med Sci Sports Exerc, 42, 1162-73.
BOLDYREV, A. A., ALDINI, G. & DERAVE, W. 2013. Physiology and pathophysiology of carnosine. Physiol Rev, 93, 1803-45.
SAUNDERS, B., V, D. E. S. P., LF, D. E. O., V, D. A. E. S., RP, D. A. S., RIANI, L., FRANCHI, M., GONCALVES, L. S., HARRIS, R. C., ROSCHEL, H., ARTIOLI, G. G., SALE, C. & GUALANO, B. 2017. Twenty-four Weeks of beta-Alanine Supplementation on Carnosine Content, Related Genes, and Exercise. Med Sci Sports Exerc, 49, 896-906.
TREXLER, E. T., SMITH-RYAN, A. E., STOUT, J. R., HOFFMAN, J. R., WILBORN, C. D., SALE, C., KREIDER, R. B., JAGER, R., EARNEST, C. P., BANNOCK, L., CAMPBELL, B., KALMAN, D., ZIEGENFUSS, T. N. & ANTONIO, J. 2015. International society of sports nutrition position stand: Beta-Alanine. J Int Soc Sports Nutr, 12, 30.