The influence of β-alanine supplementation on recovery biomarkers in adults: A systematic review and meta-analysis

Background: Clinical studies, investigating the effect of β-Alanine (BA) supplementation on recovery biomarkers in physically active individuals, have generated inconsistent results. This systematic review and meta-analysis study aimed to clarify the clinically relevant dietary effects of BA supplementation. Methods: A comprehensive search was done in the electronic databases of Scopus, PubMed, ISI Web of Science and Embase from inception to 2020. Meta-analysis was done using the random-effects model. Pooled effect size was evaluated using standard mean difference (SMD) and 95% confidence intervals (CI). Heterogeneity of between-study was evaluated according to Cochran’s Q test and I2. Subgroup analysis was conducted to identify the potential sources of heterogeneity. Results: Overall, 32 studies were included in the current study. The results suggested that BA supplementation increases carnosine level significantly (SMD: 0.22mmol/L, 95%CI: -0.17,0.61, P=0.27) but no effect was shown about lactate, fatigue, VO2, PH and bicarbonate (HCO3-) (P>0.05). Subgroup analysis revealed a significant association of VO2, carnosine and fatigue with supplementation dosage, gender and duration of administration respectively. Conclusion: BA supplementation emerged its beneficial effects on enhancing carnosine level which highlights its ergogenic effects. In contrast, no significant effects had been shown in term of fatigue delay and blood levels of lactate, HCO3-, PH, and VO2 value. These results warrant more investigation in a prospective design to clarify the exact mechanism in this way.