ID 1578 - 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.

2.3. Zwiększenie siły mięśni (ID 1578, 1583, 1587)

The claimed effects are “increasing strength”, “HMB and training adaptations”, and “HMB and changes in muscle strength during training”. The Panel assumes that the target population is adults performing resistance training to improve muscle strength.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to an increase in muscle strength. In sports, muscle strength is sometimes a limiting factor for physical performance.
The Panel considers that an increase in muscle strength 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).

3.3. Zwiększenie siły mięśni (ID 1578, 1583, 1587)

Ten of the 11 RCTs considered in the meta-analysis by Rowlands and Thomson (2009), and which included 14 intervention arms, assessed the effects of HMB supplementation on measures of overall, upper and lower body muscular strength. The strength measure used was 1RM in seven studies (Gallagher et al., 2000; Jówko et al., 2001; Kreider et al., 1999; Panton et al., 2000; Ransone et al., 2003; Thomson et al., 2009; Vukovich and Dreifort, 2001), 3RM in two studies (O'Connor and Crowe, 2003; Slater et al., 2001) and a strength index, calculated as the average weight lifted to failure (4-6 repetitions) during three sets multiplied by the number of repetitions the weight was lifted, in one study (Nissen et al., 1996). There was a small but statistically significant effect of HMB on overall average muscle strength when all studies and subjects were combined (mean=3.7 %, 90 % CI 1.3 % to 6.1 %). This effect was due to the significant changes observed in untrained individuals (mean=6.6 %, 90 % CI 0.9 % to 2.3 %), particularly in lower body strength (mean=9.9 %, 90 % CI 4 % to 15.8 %). No significant changes in muscle strength were observed in the upper body for untrained lifters, or for trained lifters in overall, upper body or lower body strength. No explanation for the differential effects of HMB supplementation observed in trained vs. untrained subjects, or in upper vs. lower body strength in untrained subjects, has been provided. The Panel notes that the results from this meta-analysis with respect to the effect of HMB consumption on muscle strength are inconsistent. The Panel also notes that no significant effect of HMB consumption on muscle strength was shown in the target population (i.e. active individuals who are performing resistance training to improve muscle strength) for the claim.
An effect of HMB on protein turnover leading to an increase in lean body mass, and an effect of HMB on the reduction of skeletal muscle damage during exercise, have been hypothesised as the mechanisms by which HBM could improve muscle strength. However, the Panel notes that no evidence has been provided for any of these mechanisms (see sections 3.1 and 3.2).
In weighing the evidence, the Panel took into account that the results from a meta-analysis of RCTs with respect to the effect of HMB consumption on muscle strength are inconsistent, that no significant effect of HMB consumption on muscle strength was shown in the target population for the claim, and that no evidence for a mechanism by which HMB could exert the claimed effect was provided.
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 increase in muscle strength.

Warunki i możliwe ograniczenia stosowania oświadczenia

The product must contain at least 1 gram HMB per serving Claim to be used for foods for active individuals

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