ID 1584 -
Beta-hyroksy beta-metylomaślan (też z kwasem ketoizokarponowym)
PL: Beta-hyroksy beta-metylomaślan (też z kwasem ketoizokarponowym)
EN: HMB (B- hydroxy B- methylbutyrate monohydrate)
Pdf: β-hydroxy β-methylbutyrate monohydrate (with α-ketoisocaproic acid)
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claims is “HMB (β-hydroxy β-methylbutyrate monohydrate)” and “HMB and HMB/KIC combinations”.
From the information provided, the Panel assumes that the food constituent that is the subject of the health claims is HMB, either alone or in combination with α-ketoisocaproic acid (KIC).
β-Hydroxy β-methylbutyric acid (HMB), or β-hydroxy β-methylbutyrate, is a metabolite of the amino acid leucine. HMB can be synthesised in the human body (about 0.2-0.4 g/day) and is usually available in supplements as a calcium salt. KIC is also an intermediate metabolite of leucine. Both HMB and KIC can be measured in food by established methods.
The Panel considers that the food constituent, either HMB alone or in combination with KIC, which is the subject of the health claims, is sufficiently characterised.
2.1. Ograniczenie uszkodzeń mięśni podczas ćwiczeń (ID 1577, 1584)
The claimed effects are “minimize muscle protein breakdown” and “HMB and exercise induced muscle breakdown”. The Panel assumes that the target population is adults performing resistance exercise.
In the context of the proposed wordings and the references provided, the Panel assumes that the claimed effects relate to the reduction of damage to muscle tissue during exercise.
The Panel considers that reduction of muscle tissue damage during exercise is a beneficial physiological effect.
3. Naukowe uzasadnienia wpływu na zdrowie człowieka
Some of the references provided for the scientific substantiation of the claims evaluated in this opinion were studies and narrative reviews which addressed the effects of HMB on outcomes (e.g. fat metabolism, hepatic and renal function, and cardiovascular system function) unrelated to the claimed effects, or which did not include original data for the scientific substantiation of the claim. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claims.
A meta-analysis of randomised controlled trials (RCTs) (Rowlands and Thomson, 2009) on the effects of HMB on outcomes of body composition, muscle strength and muscle damage included the majority of the publications submitted, and from which conclusions could be drawn for the scientific substantiation of the claims. The meta-analysis included 10 RCTs with a parallel design and one RCT with a cross-over design (with one-week washout between interventions). In these trials (17 intervention arms), 12 intervention arms assessed measures of muscle strength, 16 intervention arms provided body composition estimates, and eight intervention arms reported on muscle damage assessed by creatine kinase (CK) concentrations. The meta-analysis comprised 394 trained (n=259) and untrained (n=135) weight lifters on resistance training for 5±6 h/week (range 3-20 h/week), and interventions lasting 3-9 weeks. The HMB dose in all but two studies was 3.0 g/day (range 1.5-6.0 g/day).
Another meta-analysis of RCTs on the effects of HMB supplementation on lean body mass and strength during resistance training, and which included a literature search from 1967 to 2001, was provided (Nissen and Sharp, 2003). This meta-analysis included only seven RCTs on HMB (and 9 intervention arms), all of which were included in the meta-analysis by Rowlands and Thomson (2009). The Panel considers that this meta-analysis does not provide evidence for the scientific substantiation of the claims in addition to that of the meta-analysis by Rowlands and Thomson (2009).
3.1. Ograniczenie uszkodzeń mięśni podczas ćwiczeń (ID 1577, 1584)
In the meta-analysis by Rowlands and Thomson (2009), a total of five studies, including eight effect estimates, addressed the effects of HMB supplementation on muscle damage during resistance training by means of blood concentrations of CK as a marker of muscle membrane damage (Jówko et al., 2001; Kreider et al., 1999; Kreider et al., 2000; Nissen et al., 1996; Panton et al., 2000). All intervention arms used doses of HMB of 3.0 g/day except one (i.e. 1.5 g/day). Five arms used untrained subjects whereas three used trained subjects. All subjects were young males (87 in the intervention and 88 in the control group). No significant effect of HMB consumption on CK concentrations was observed compared to placebo.
Two studies, which addressed the effect of HMB on measures of muscle damage, and which were not included in the meta-analysis, were also provided (Knitter et al., 2000; van Someren et al., 2005).
In the cross-over RCT by van Someren et al. (2005), six non resistance trained male subjects performed an exercise protocol designed to induce muscle damage on the dominant or non-dominant arm on two separate occasions. Subjects consumed HMB in combination with KIC (3.0 g HMB and 0.3 g KIC, daily) and placebo (3.0 g corn flour) given in three equal doses during the day, for 14 days
prior to exercise. The order of the interventions was randomised. One repetition maximum (1RM), plasma CK activity, delayed onset muscle soreness (DOMS), limb girth, and range of motion (ROM) were determined pre-exercise, at 1 h, 24 h, 48 h, and 72 h post-exercise. The Panel notes that the primary outcome of the study was not identified, that no power calculations were performed, and that no control for multiplicity of analyses was applied. HMB and KIC supplementation significantly attenuated the CK response compared to placebo (p<0.05). The Panel considers that limited conclusions can be drawn from this study for the scientific substantiation of the claim.
In the RCT by Knitter et al. (2000), subjects (n=16, 8 males) were paired according to their 2-mile run times and past running experience. Each pair was randomly assigned a treatment of either HMB (3.0 g/day) or placebo (rice maltodextrin). After six weeks of daily training and supplementation, all subjects participated in a prolonged run (20-km course). CK and lactate dehydrogenase (LDH) activities were measured before and after the run to assess muscle damage. Three subjects from the placebo group withdrew from the study, and data analyses were performed in the sample of completers only (n=5 placebo, n=8 HMB). Power calculations were not performed. The Panel notes that all drop outs belonged to the placebo group, and that drop outs (and therefore the breaking of the initial group matching by training status) were not taken into account in data analysis. The Panel considers that no conclusions can be drawn from this study for the scientific substantiation of the claim.
In weighing the evidence, the Panel took into account that although one small RCT with methodological limitations reported a significant effect of HMB in combination with KIC on surrogate measures of muscle damage during resistance training, one meta-analysis of RCTs which included five studies and eight intervention arms did not show an effect of HMB supplementation on muscle tissue damage during exercise.
The Panel concludes that a cause and effect relationship has not been established between the consumption of HMB, either alone or in combination with KIC, and reduction of muscle tissue damage during exercise.
Warunki i możliwe ograniczenia stosowania oświadczenia
Minimum of 3g per day HMB and 0.3g KIC daily for 2 weeks (1)
