Leucine Metabolites Do Not Enhance Training-induced Performance or Muscle Thickness

Abstract

No leucine metabolite resulted in any ergogenic effects on any outcome variable. Supplementation with leucine metabolites - α-HICA, HMB-FA, or HMB-Ca - is not a supplementation strategy that improves muscle growth and strength development in young adult men.

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

“…This may be particularly true, when sufficient protein and energy intake is provided [22,23]. The additional effects of HMB on body composition over and above regular protein intake might therefore only be observed in untrained participants, the elderly population, and bedridden people, but not in resistancetrained athletes [22]. HMB did not affect any of the performance measures that were assessed in the present study.…”

“…Because segmental measurements for estimating FFM reflect more closely the underlying biophysical model of BIS to whole-body BIS (assumption of isotropic conductor with homogeneous cross-sectional area and consistent proportions specific tissues), we expected segmental measurements to be more accurate and precise than whole-body FFM estimations [27,28,31]. The methodological difference between single slice recordings and total limb estimations in tracking changes in segmental hypertrophy may also explain the lack of detecting an ergogenic effect associated with HMB supplementation in two very recent studies, employing similar study designs [20,22]. However, it should also be noted that the subjects in the present study were untrained men, whereas the aforementioned study were performed in resistance-trained men.…”

“…It is possible that the mTOR and ubiquitinproteasome proteolytic pathways are already maximized in resistance-trained athletes due to high training loads and the time course of long-term physiological adaptations and explain why muscle protein synthesis may not be augmented in this population. This may be particularly true, when sufficient protein and energy intake is provided [22,23]. The additional effects of HMB on body composition over and above regular protein intake might therefore only be observed in untrained participants, the elderly population, and bedridden people, but not in resistancetrained athletes [22].…”

“…There is also increasing interest whether HMB supplementation can augment strength training-induced gains in FFM when a highprotein diet is provided [5,[20][21][22][23]. Recent studies suggest that protein balance is the critical driver for strength-training induced changes in muscle mass in resistance-trained men [20,22,23]. Accordingly, it has been questioned whether HMB supplementation can provide any additional benefits over and above regular protein intake on body composition and performance.…”

Importance of Cheese Whey Processing: Supplements for Sports Activities – a Review

“…However, the need for higher intake was shown by Churchward-Venne et al [2014], who found that adding 5 g leucine to 6.25 g WPI stimulates MPS. Despite these results, there are studies proving that leucine supplementation associated or not to WP supplement does not exert additional effects on MPS [Grala et al, 2017;Teixeira et al, 2018]. However, studies are still required to elucidate the infl uence of leucine on MPS as a potential nutritional ergogenic resource [Grala et al, 2017].…”