Does HMB Enhance Body Composition in Athletes? A Systematic Review and Meta-analysis

Abstract

Holland, BM, Roberts, BM, Krieger, JW, and Schoenfeld, BJ. Does HMB enhance body composition in athletes? A systematic review and meta-analysis. J Strength Cond Res 36(2): 585-592, 2022-The purpose of this article was to systematically review and meta-analyze the current literature to determine the effects of HMB on body composition in athletes. Studies were deemed eligible for inclusion if they met the following criteria: (a) were an experimental design published in a peer-reviewed, English-language journal; (b) included human athletic populations; (c) assessed body mass (BM), fat mass (FM), or fat-free mass (FFM) using a validated measure; (d) and had a minimum supplementation period of 4 weeks. Separate analyses were performed for BM, FM, and FFM using robust variance random-effects meta-regression for multilevel data structures, with adjustments for small samples. The final analysis of BM comprised a total of 208 subjects from 7 studies. Analysis of FFM and FM encompassed 5 studies comprising 161 subjects and 5 studies comprising 128 subjects, respectively. The principal finding of this analysis suggests HMB may have a small, positive impact on FFM in athletes (0.30 6 0.13; 95% confidence interval [CI]: 20.07 to 0.68; p 5 0.08), although this seems specific to when protein intake is suboptimal (,1.6 g•kg 21 •d 21 ). Consistent with previous research on athletes, HMB demonstrated no significant effect on BM (20.02 6 0.04; 95% CI: 20.14 to 0.10; p 5 0.70) and a small, nonsignificant effect on FM (20.33 6 0.23; 95% CI: 20.96 to 0.31; p 5 0.22). More research is required to establish HMB's influence on FFM in athletes. It is also important to consider the dosage of HMB and training parameters of athletes because these will likely influence the efficacy of supplementation.

Supplementation with the Leucine Metabolite β-hydroxy-β-methylbutyrate (HMB) does not Improve Resistance Exercise-Induced Changes in Body Composition or Strength in Young Subjects: A Systematic Review and Meta-Analysis

“…This systematic review and meta-analysis showed that HMB ingestion does not augment RET-induced changes in body composition or strength following weeks or RET (7.6 ± 4.0 wk) in adults between the ages of 18 and 45 years old. These findings are in line with results from previous meta-analyses focusing on HMB supplementation [7,11,28]. Nevertheless, a small significant effect was observed for TBM.…”

“…Eleven studies might be considered a small number when drawing final conclusions. However, this analysis is in line with some of the recently published meta-analyses studying HMB [11,28]. In addition, although there was no significant heterogeneity observed in the analysis of strength gains, the variability between RET protocols might be another limiting factor.…”

“…Although, this was not one of the main objectives of the present meta-analysis when designing inclusion and exclusion criteria, our conclusions derived mainly from studies in which untrained persons were studied ( Table 2). This is important because two recent meta-analyses [11,28] showed no substantive effects of ingesting HMB when combined with resistance exercise, but on studies conducted mostly in athletes. Therefore, it seems reasonable to conclude that our data, viewed collectively with previous work [11,28], show that HMB is not a valuable nutritional supplement to be consumed by athletes or non-athletes aiming to improve resistance exercise-induced gains in FFM and strength.…”

“…Additionally, six studies utilized RET programs of at least 8 weeks (Table 2). Protein ingestion was also cited as a potential limiting factor influencing resistance exercise responses in HMB-supplemented individuals [28]. Holland et al [28] postulated that HMB might not enhance RET gains in individuals already ingesting >1.6 g of protein/day.…”

“…Protein ingestion was also cited as a potential limiting factor influencing resistance exercise responses in HMB-supplemented individuals [28]. Holland et al [28] postulated that HMB might not enhance RET gains in individuals already ingesting >1.6 g of protein/day. Still, only two of the seven selected studies by their meta-analysis reported daily protein ingestion of >1.6 g of protein/day and additional four studies did not report protein ingestion.…”