Combined protein and calcium β-hydroxy-β-methylbutyrate induced gains in leg fat free mass: a double-blinded, placebo-controlled study

Abstract

Background: The leucine metabolite β-hydroxy-β-methylbutyrate (HMB) is widely used as an ergogenic supplement to increase resistance-training induced gains in fat free mass (FFM) and strength in healthy adults. Recent studies have questioned the effectiveness of HMB, particularly when a high protein diet is habitually consumed. To investigate the additive resistance-training induced effects of HMB and protein in untrained individuals, we conducted a randomized double-blind, placebo-controlled study that compared the effects of combined protein and HMB supplementation to protein supplementation alone on FFM and muscle strength after 12-week resistance training. Methods: Sixteen healthy men (22 ± 2 yrs) performed a periodized resistance-training program for twelve weeks (four sessions per week). The program comprised two mesocycles, characterized by a linear periodization and nonlinear periodization, respectively, and separated by a 1-week tapering period. All participants received 60 g of whey protein on training days and 30 g of whey protein (WP) on non-training days. Participants were randomly assigned to additionally receive 3 g of calcium HMB (WP + HMB) or a placebo (WP + PLA). Body composition and physical fitness were tested before and after the 12-week training program. Whole-body and arm and leg fat free mass (FFM) were assessed by bioimpedance spectroscopy; upper arm and leg fat free cross sectional areas were also quantified using magnetic resonance imaging (MRI); upper and lower body strength were measured by Onerepetition maximum (1-RM) bench press and leg press. Results: Whole-body and segmental FFM increased in both groups (P < 0.001). However, gains in leg FFM were higher in WP + HMB vs. WP + PLA (arm FFM: + 6.1% vs. + 9.2%, P = 0.2; leg FFM: + 14.2% vs. + 7.0%, P < 0.01). No change in fat mass was observed (P = 0.59). 1-RM increased in both groups (P < 0.001). Conclusions: Combined protein and HMB supplementation resulted in segmental, but not whole-body increases in FFM compared to protein supplementation alone. These findings could explain some of the controversial effects of HMB reported in previous studies and have practical implications for maximizing training-induced gains in FFM and clinical conditions associated with skeletal muscle deconditioning such as aging, sedentary lifestyles, bed rest and spaceflight.

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

“…However, the placebo group in Stahn et al [39] (ingesting 30 g whey protein only) did not actually show a significant increase in whole-body FFM. Therefore, the conclusions of that study [39] are perplexing, since it would be expected that 12 weeks of RET would result in a significant increase in whole-body FFM even in the placebo group [9,44]. Nevertheless, the fact that HMB is not effective in producing significant effects in young subjects performing resistance exercise does not exclude the possibility of potential effects in other populations or physiological states.…”

“…Therefore, it is not known if the acute effects of HMB on protein synthesis [15,16] are additive to the expected response to the ingestion of proteins or a resistance exercise bout, but it would seem unlikely so long as leucine was ingested at a sufficient dose [15]. Nevertheless, some studies [2,3,9,39], including one from our group [9], have tested the long-term effects of ingesting HMB together with high-quality protein on the adaptation to resistance exercise. Two of these studies [3,9], showed no significant benefit to body composition changes or strength gains caused by RET of adding HMB to protein-containing nutritional supplements, 75 g and 50 g respectively [3,9].…”

“…In contrast, Nissen et al [2] showed a higher increase in lean body mass and strength when HMB was added to a nutritional supplement containing 37 g of milk protein. Also, Stahn et al [39] showed that ingesting 3 g of HMB-Ca added to 30 g of whey protein was able to increase fat-free mass in young men.…”

“…Two additional studies were excluded (Table S2) after visual funnel plots symmetry analysis ( Figure S1A) [35,36]. No asymmetry was detected when considering the remaining studies [2,[4][5][6][8][9][10]12,[37][38][39] (Figure S1B). One study received high risk of bias classification in three domains (selection bias, performance bias and other bias) [2].…”

The Effects of Calcium-β-Hydroxy-β-Methylbutyrate on Aging-Associated Apoptotic Signaling and Muscle Mass and Function in Unloaded but Nonatrophied Extensor Digitorum Longus Muscles of Aged Rats

“…HMB has been shown to improve strength and fatigue resistance in quadriceps muscles of humans including the elderly in multiple studies especially when HMB treatment was combined with exercise [ 53 , 95 , 103 , 126 – 130 ]. However, we did not observe an increase in muscle force or fatigue resistance in the EDL muscles of Ca-HMB-treated rats after unloading by HS or during reloading as compared to rats that received water.…”