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.

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.

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.

2.4. Zwiększenie wydolności fizycznej (ID 1580, 1581)

The claimed effects are “increasing exercise lactate threshold and VO2 peak”, and “HMB and aerobic metabolism”. The Panel assumes that the target population is adults performing endurance exercise.
In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effects refer to an increase in endurance performance. Endurance performance relates to the ability to complete certain tasks with higher intensity, faster, or with a higher power output when performing long-term exercise.
The Panel considers that an increase in endurance performance is a beneficial physiological effect.

2.5. Wpływ na regenerację mięśni szkieletowych (ID 1586)

The claimed effect is “HMB and normal muscle repair”. The Panel assumes that the target population is adults performing resistance exercise.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to the rebuilding of structural protein within skeletal muscle tissue after exercise which has caused muscle damage.
The Panel considers that skeletal muscle tissue repair is a beneficial physiological effect.

2.6. Szybsze ustępowanie zmęczenia mięśni po wysiłku (ID 1576, 1585)

The claimed effects are “sport exercise recovery” and “HMB and muscle recovery after training”. The Panel assumes that the target population is adults performing strenuous exercise.
The Panel assumes that the claimed effects refer to muscle fatigue recovery after exercise.
Fatigue can be defined as the loss of peak force or power output. Therefore, muscle fatigue recovery can be defined as the regain of maximal muscle strength or muscle power after performance of strenuous exercise which has induced muscle fatigue.
The Panel considers that faster recovery from muscle fatigue after exercise is a beneficial physiological effect.

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.

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.

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.

3.4. Zwiększenie wydolności fizycznej (ID 1580, 1581)

Two of the human intervention studies provided assessed the effects of HMB on measures of maximal oxygen consumption (VO2 max), on ventilatory threshold or on the onset of blood lactate accumulation (Lamboley et al., 2007; Vukovich and Dreifort, 2001), but the studies did not include any measure of endurance performance. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
In a RCT by O’Connor and Crowe (2003), the effects of a 6-week oral supplementation with HMB (3.0 g/day) vs. a mixture of HMB and creatine monohydrate (3.0 g/day HMB plus 3.0 g/day creatine) on aerobic and anaerobic capacity, peak power and total work during a cycling test in highly trained
rugby players were assessed. The control group was self-selected and received no treatment. The Panel notes that randomisation and blinding were only applied to subjects assigned to the two intervention groups. No statistically significant effect of HMB on peak power or total work was observed compared to the control group. The Panel notes the important limitations of the study design, and considers that no conclusions can be drawn for the scientific substantiation of the claim.
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 endurance performance.

3.5. Wpływ na regenerację mięśni szkieletowych (ID 1586)

No references addressing the effects of HMB supplementation in humans on measures of skeletal muscle tissue repair were 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 skeletal muscle tissue repair.

3.6. Szybsze ustępowanie zmęczenia mięśni po wysiłku (ID 1576, 1585)

In the RCT by Paddon-Jones et al. (2001), non resistance trained male subjects were randomly assigned to consume 40 mg/kg body weight per day of HMB (n=8) or placebo (maltodextrin calcium carbonate, n=9) for six days prior to a bout of 24 maximal isokinetic eccentric contractions of the elbow flexors, and this protocol continued throughout post testing. Muscle soreness, upper arm girth, and torque measures were assessed pre-exercise, 15 min post-exercise, and 1, 2, 3, 4, 7, and 10 days post-exercise. Power calculations were not performed. No pre-test differences between HMB and control groups were observed, and both groups performed a similar amount of eccentric work during the main eccentric exercise bout. HMB supplementation had no effect on swelling, muscle soreness, or torque following the damaging eccentric exercise bout. The Panel notes that this study does not show an effect of HMB on faster recovery from muscle fatigue after exercise.
No other references which addressed the effects of HMB supplementation in humans on measures of muscle fatigue recovery after exercise were provided.
In weighing the evidence, the Panel took into account that the one human intervention study provided from which conclusions could be drawn for the scientific substantiation of the claim did not show an effect of HMB on faster recovery from muscle fatigue after 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 faster recovery from muscle fatigue after exercise.