Request for Clarification:
Pitchford et al. suggest that the supplements used by McIntosh et al. (3) contained no beta-Hydroxy beta-Methylbutyrate (HMB) leading to the null hypothesis on strength measures, the significant negative effect on YoYo running performance, and increase in body mass. However, it should be noted that the product tested by Pitchford et al. “Maximum HMB” (Reactiv Supplements) is not the same product as used by McIntosh et al. who used Ca-HMB (Reactiv Supplements, Auckland, New Zealand). Reactiv Supplements supplied a certificate of analysis for their Ca-HMB capsules, stating 84% of HMB content. Furthermore, the original source of maximum HMB differs to that of Ca-HMB; therefore, it is difficult to infer the analysis by Pitchford et al. to the McIntosh et al. (3) findings. Although independent testing of a commercially available supplement would be the gold-standard procedure, this is often beyond the means of athletes, sports teams, and many research articles.
If as suggested 2 placebo trials were provided, this could explain only the strength measures and not the body mass nor the decreased aerobic performance results. A recent meta-analysis in well-trained and competitive athletes showed HMB supplementation resulted in no significant effects on muscle strength (6) in line with McIntosh et al. (3).
Studies investigating aerobic capacity/performance with HMB supplementation have mainly recruited untrained or recreationally trained participants, and it seems that the effects of HMB on untrained and highly trained participants are different (2,4). Beta-Hydroxy beta-Methylbutyrate was shown to improve cycling performance in elite rowers (1) and trained cyclists (8); however, differences in responses to HMB may be between endurance athletes and those engaged in more resistance training (5).
The one other study in highly trained rugby players, using a running protocol showed no beneficial effect of HMB on aerobic performance (5). It is possible that the increased body mass seen in the study by McIntosh et al. (3) resulted in a decrement in running performance. Four of the 6 participants on HMB saw a reduction in YoYo performance compared with an improvement by all the placebo groups.
Overall, it seems that the findings of McIntosh et al. (3) are supported by the previous research (5,6) suggesting HMB supplementation is not beneficial to elite rugby players.
However, it highlights a key issue for athletes that despite due diligence in supplement procurement, they still may not be obtaining the supplement they believe, adding support to the food first approach advocated by many sports nutritionists.
1. Durkalec-Michalski K, Jeszka J. The efficacy of a beta-hydroxy-beta-methylbutyrate supplementation on physical capacity, body composition and biochemical markers in elite rowers: A randomised, double-blind, placebo-controlled crossover study. J Int Soc Sports Nutr 12: 31, 2015.
2. Lamboley CR, Royer D, Dionne IJ. Effects of beta-hydroxy-beta-methylbutyrate on aerobic-performance components and body composition in college students. Int J Sport Nutr Exerc Metab 17: 56–69, 2007.
3. McIntosh ND, Love TD, Haszard JJ, Osborne HR, Black KE. Beta-hydroxy beta-methylbutyrate (HMB) supplementation effects on body mass and performance in elite male rugby union players. J Strength Cond Res 32: 19–26, 2018.
4. Miramonti AA, Stout JR, Fukuda DH, Robinson EH IV, Wang R, La Monica MB, et al. Effects of 4 weeks of high-intensity interval training and beta-hydroxy-beta-methylbutyric free acid supplementation on the onset of neuromuscular fatigue. J Strength Cond Res 30: 626–634, 2016.
5. O'Connor DM, Crowe MJ. Effects of beta-hydroxy-beta-methylbutyrate and creatine monohydrate supplementation on the aerobic and anaerobic capacity of highly trained athletes. J Sports Med Phys Fitness 43: 64–68, 2003.
6. Sanchez-Martinez J, Santos-Lozano A, Garcia-Hermoso A, Sadarangani KP, Cristi-Montero C. Effects of beta-hydroxy-beta-methylbutyrate supplementation on strength and body composition in trained and competitive athletes: A meta-analysis of randomized controlled trials. J Sci Med Sport 21: 727–735, 2018.
7. Silva VR, Belozo FL, Micheletti TO, Conrado M, Stout JR, Pimentel GD, et al. beta-hydroxy-beta-methylbutyrate free acid supplementation may improve recovery and muscle adaptations after resistance training: a systematic review. Nutr Res 45: 1–9, 2017.
8. Vukovich MD, Dreifort GD. Effect of beta-hydroxy beta-methylbutyrate on the onset of blood lactate accumulation and V(O)(2) peak in endurance-trained cyclists. J Strength Cond Res 15: 491–497, 2001.