Effects of beta-alanine supplementation on body composition: a GRADE-assessed systematic review and meta-analysis

Abstract

Purpose Previous studies have suggested that beta-alanine supplementation may benefit exercise performance, but current evidence regarding its effects on body composition remains unclear. This systematic review and meta-analysis aimed to investigate the effects of beta-alanine supplementation on body composition indices. Methods Online databases, including PubMed/Medline, Scopus, Web of Science, and Embase, were searched up to April 2021 to retrieve randomized controlled trials (RCTs), which examined the effect of beta-alanine supplementation on body composition indices. Meta-analyses were carried out using a random-effects model. The I 2 index was used to assess the heterogeneity of RCTs. Results Among the initial 1413 studies that were identified from electronic databases search, 20 studies involving 492 participants were eligible. Pooled effect size from 20 studies indicated that beta-alanine supplementation has no effect on body mass (WMD: −0.15 kg; 95% CI: −0.78 to 0.47; p = 0.631, I 2 = 0.0%, p = 0.998), fat mass (FM) (WMD: −0.24 kg; 95% CI: −1.16 to 0.68; p = 0.612, I 2 = 0.0%, p = 0.969), body fat percentage (BFP) (WMD: −0.06%; 95% CI: −0.53 to 0.40; p = 0.782, I 2 = 0.0%, p = 0.936), and fat-free mass (FFM) (WMD: 0.05 kg; 95% CI: −0.71 to 0.82; p = 0.889, I 2 = 0.0%, p = 0.912). Subgroup analyses based on exercise type (resistance training [RT], endurance training [ET], and combined training [CT]), study duration (<8 and ≥8 weeks), and beta-alanine dosage (<6 and ≥6 g/d) demonstrated similar results. Certainty of evidence across outcomes ranged from low to moderate. Conclusions This meta-analysis study suggests that beta-alanine supplementation is unlikely to improve body composition indices regardless of supplementation dosage and its combination with exercise training. No studies have examined the effect of beta-alanine combined with both diet and exercise on body composition changes as the primary variable. Therefore, future studies examining the effect of the combination of beta-alanine supplementation with a hypocaloric diet and exercise programs are warranted.

Carnosine supplementation improves glucose control in adults with pre-diabetes and type 2 diabetes: a randomised controlled trial

“…Although our study found a decrease of 0.74 kg/m 2 in BMI in the carnosine group (p=0.045) after 14-week supplementation compared to the placebo; with no significant change in weight between follow-up and baseline, this is unlikely to be clinically relevant, and is potentially random. Our study found no change in waist circumference or waist-to-hip ratio after carnosine supplementation, in line with previous studies of similar cohorts 16,23 . Liu et al 36 reported in one trial that carnosine as part of a combined supplement with cinnamon and chromium increased lean mass, which is in contrast to our trial.…”

“…They found that despite addition of exercise, there were no reductions in body weight, fat mass, body fat and fat-free mass 38 in any cohort; findings echoed in another trial of β-alanine and exercise combined 39 . Another recent meta-analysis of 426 participants found no effect of supplementation on any measure of body composition, and no interaction effects resulting from resistance training, endurance training or combined training 23 . This data, and ours provides evidence that neither carnosine nor β-alanine supplementation seems to affect body composition directly, with or without complimentary exercise in adults without obesity.…”

“…We hypothesize that oral carnosine supplementation for 14 weeks would improve glucose metabolism and reduce insulin levels in patients with prediabetes or T2DM compared to placebo. A recent systematic review and meta-analysis of 20 studies determined that b-alanine, a precursor to carnosine, had no effect on body composition in athletes 23 , however it is unknown whether it has any effect in patients with cardiometabolic disease. In our trial, we aim to utilize DXA to further elucidate the effect of carnosine supplementation on whole body mass, fat percentage, fat mass and fat free mass in group of individuals with overweight but not obese.…”

The effects of beetroot and nitrate supplementation on body composition: a GRADE-assessed systematic review and meta-analysis

“…Data were extracted from eligible studies by three investigators (VF, RA), and a head investigator (DA) performed the final evaluation. The obtained data are (1) surname of the first author, (2) place of study, (3) year of publication, (4) duration of the study, (5) type and dose of BR or nitrate supplements, (6) sex, (7) age, (8) BMI and (9) health status of the participants.…”

“…Various methods are recommended to ameliorate body composition such as adherence to different dietary approaches, along with exercise; they have mostly focused on increasing lean body mass and reducing body fat and/or weight (2,3) . In addition to dietary and exercise interventions, dietary supplements have received increasing attention for body composition improvement among the general population and athletes (4,5) . One of these dietary supplements is beetroot juice (BRJ) (6) .…”