ID 1582 -
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.
2.2. Zwiększenie beztłuszczowej masy ciała (ID 1579, 1582, 1583)
The claimed effects are “increasing mass”, “HMB and lean body mass”, and “HMB and training adaptations”. The Panel assumes that the target population is physically active individuals in the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to an increase in lean body mass relative to body fat mass.
The Panel considers that an increase in lean body mass 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).
3.2. Zwiększenie beztłuszczowej masy ciała (ID 1579, 1582, 1583)
Ten of the 11 RCTs considered in the meta-analysis by Rowlands and Thomson (2009), and which included 16 intervention arms, assessed the effects of HMB supplementation on lean body mass and reported size estimates. Body composition was assessed by skin fold thickness in three trials (Gallagher et al., 2000; Panton et al., 2000; Ransone et al., 2003), by bioelectrical impedance analysis (BIA) in two trials (Jówko et al., 2001; Thomson et al., 2009), by total body electrical conductivity (TOBEC) in one trial (Nissen et al., 1996), and by dual-energy x-ray absorptiometry (DXA) in four trials (Kreider et al., 1999; Kreider et al., 2000; Slater et al., 2001; Vukovich et al., 2001). No significant effect of HMB on changes in fat-free mass was observed in either trained (mean=0.8 %, 90 % CI -0.4 % to 2 %) or untrained (mean=0.9 %, 90 % CI -0.2 % to 2 %) subjects. The Panel notes that skin fold thickness, BIA and TOBEC may not be as reliable methods as DXA to assess changes in body composition in short-term intervention studies. The Panel also notes that none of the studies which assessed changes in lean body mass using DXA found a significant effect of HMB compared to placebo.
An additional RCT, which assessed the effects of HMB supplementation on lean body mass and which was not included in the meta-analysis by Rowlands and Thomson (2009), was provided (Lamboley et al., 2007). College students were randomly assigned to consume either HMB (3 g/day; n=8, 4 men) or placebo (placebo not reported; n=8, 4 men) for a 5-week supplementation period during which they underwent interval training three times a week on a treadmill. Body composition was assessed by DXA before and after training. No significant differences between groups were observed with respect to changes in body composition, including lean body mass.
In weighing the evidence, the Panel took into account that a meta-analysis of ten RCTs, and one additional RCT not included in the meta-analysis, did not show a significant effect of HMB consumption on lean body mass during training compared to placebo.
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 lean body mass.
Warunki i możliwe ograniczenia stosowania oświadczenia
Minimum of 3g HMB per day for 2 weeks combined with resistance training (10)
