ID 1535 - Kreatyna

PL: Kreatyna
EN: Creatine
Pdf: creatine

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claims is creatine.
Creatine is a non-essential nitrogenous organic acid that occurs in vertebrates, and it is also synthesised in the human body from L-arginine, glycine and L-methionine. Approximately 95 % of the creatine pool in the body is located in skeletal muscle. The content of creatine in foods can be measured by established methods.
The Panel considers that the food constituent, creatine, which is the subject of the health claims, is sufficiently characterised.

2.2. Wzrost wytrzymałości (ID 1527, 1535)

The claimed effect is “increasing workout capacity”. The Panel assumes that the target population is adults performing endurance exercise.
In the context of the proposed wordings, the Panel assumes that the claimed effect refers to an increase in endurance capacity. Endurance capacity refers to the exercise time to self-reported fatigue when exercising at a constant workload or speed.
The Panel considers that an increase in endurance capacity is a beneficial physiological effect.

3. Naukowe uzasadnienia wpływu na zdrowie człowieka - 

The references provided in the consolidated list in relation to the claims evaluated in this opinion included narrative reviews and book chapters which contained no original data for the scientific substantiation of the claims, and abstracts and conference proceedings reporting on human intervention studies in which the information provided regarding the study design, methodology and statistical analyses was insufficient for a full scientific evaluation. Some of the references reported on human intervention studies in which creatine was administered in combination with other food constituents (e.g. carbohydrates, protein, micronutrients and fatty acids) so that the study design did not allow conclusions to be drawn on the effect of creatine alone. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claims.
The references provided also included statements/consensus opinions from authoritative bodies such as the Agence Française de Sécurité Sanitaire des Aliments (AFSSA, 2000), the Scientific Committee on Food (SCF, 2001), and the American College of Sports Medicine (Terjung et al., 2000). Other consensus opinions were published by the International Society of Sports Nutrition (Buford et al., 2007; Kreider et al., 2010) and the American Dietetic Association (Rodriguez et al., 2009). Two meta- analyses of human intervention studies (Branch, 2003; Nissen and Sharp, 2003) and one “systematic review” (Rawson and Volek, 2003) which addressed the effects of creatine consumption on outcome measures relevant to the claimed effects evaluated in this opinion, considered the vast majority of individual human intervention studies submitted for the scientific substantiation of the claims. In addition, three of the references provided which reported on human intervention studies and which addressed the effects of creatine on outcome measures related to the claimed effects evaluated in this opinion were not included in the meta-analyses described below, and will be considered separately as appropriate (Izquierdo et al., 2002; Ostojic, 2004; Syrotuik et al., 2001).
The purpose of the “systematic review” by Rawson and Volek (2003) was to address the effects of creatine supplementation and concurrent resistance training on muscle strength and weight lifting performance. A total of 22 studies, 14 of which were already included in the meta-analysis by Nissen and Sharp (2003), met the inclusion criteria of Rawson and Volek (2003) and the remaining, except three (Stevenson and Dudley, 2001; Syrotuik et al., 2000; Syrotuik et al., 2001), were considered in
the meta-analysis by Branch (2003). Two of the three references were provided in the consolidated list as individual studies (Stevenson and Dudley, 2001; Syrotuik et al., 2001). The Panel notes that the methodology (e.g. literature search or other strategies used to identify pertinent references, and methodology used to calculate average percent estimates for increases in muscle strength and weight lifting performance) used in this review is poorly described and that all the studies included were already considered in the meta-analyses provided or were submitted separately. The Panel considers that no conclusions can be drawn from this review for the scientific substantiation of the claims evaluated in this opinion.
The meta-analysis by Branch (2003) included 96 publications (published up to December 2000) from 100 randomised, placebo-controlled trials, in which at least subjects were blinded to the intervention.
These studies comprised 1,847 subjects. Results were given as means SEM and 95 % CI. Mean
sample size was 19 1 (range 4 to 80). Most of the studies (93 %) were published after 1994, and most (71 % of the studies) were randomised, double-blind, placebo-controlled interventions which
addressed the effect of an acute ( 14 days) creatine loading regimen (19.7 0.5 g creatine for an
average of 9 1 days) on physical performance in mostly young trained (77 % of the studies) men (68 % of the studies). Only 22 studies investigated the effects of low dose maintenance creatine supplementation (>14 days) following acute creatine loading. Twenty-four studies included men and women as subjects. The effect of creatine supplementation on women was the focus in only 9 studies. The primary objective of the meta-analysis was to quantify the effect of creatine supplementation on body composition (including lean body mass) and exercise performance. Performance tasks were classified as single-bout or repetitive-bout exercises. The first bout of repetitive-bout exercises was
classified as a single-bout exercise task. Performance tasks of 30 sec, 30 to 150 sec, and >150 sec were also analysed separately. The effect size (ES) of creatine supplementation variable was calculated for each dependent.
The meta-analysis by Nissen and Sharp (2003) assessed the effects of longer-term creatine supplementation on lean body mass and muscle strength during resistance training. Only randomised, placebo-controlled human intervention studies, published in peer reviewed journals between 1967 and 2001, of at least 3 weeks duration and which involved a full-body resistance-training regimen two or more times per week and were conducted in healthy adults who were not under dietary restriction were included. A total of 18 studies using creatine alone as intervention met the inclusion criteria. These studies included a total of 368 subjects (n=180 in the intervention group and n=188 in the control group) with a mean age of 24 years. All studies had a parallel design, and the sample size in individual studies was generally small (mean n=10 per group). All studies included were published between 1997 and 2001. Three studies included men and women, three studies included women only, and the remaining studies were conducted in men only. Five studies were conducted in untrained subjects, and 13 studies in trained individuals. The studies averaged 7.5 weeks (range 3-13 weeks) in duration. The average loading dose of creatine was 19.4 g/day (range 10-21 g/day) for 5.3 days (range 4-7 days), and the average maintenance dose was 6.7 g/day (range 2-10.5 g/day). Changes in lean mass and strength were normalised for inclusion in the meta-analysis by conversion to percentage change per week for both treatment and placebo groups. Effect sizes (ES) of lean mass and strength changes were calculated for each dependent variable. Duration of tasks and task repetition were not considered in the analysis. All the studies included in this meta-analysis except four (Arciero et al., 2001; Bemben et al., 2001; Chrusch et al., 2001; Jowko et al., 2001) were already considered in the meta-analysis by Branch (2003).
These references will be referred to in different sections of the present evaluation as appropriate.

3.2. Wzrost wytrzymałości (ID 1527, 1535)

Among the references provided in the consolidated list, three reported on individual human intervention studies which investigated the effect of creatine supplementation on continuous (Zoeller et al., 2007) or intermittent (Izquierdo et al., 2002; Ostojic, 2004) endurance cycling or running capacity. Two of the studies tested the effects of an acute creatine load (Izquierdo et al., 2002; Ostojic, 2004), whereas one study used an acute creatine load followed by a creatine maintenance phase (Zoeller et al., 2007).
Izquierdo et al. (2002) investigated the effects of acute creatine supplementation (20 g/day for five days) on endurance capacity in trained male handball players randomly assigned to either creatine (n=9) or placebo (maltodextrin; n=10). Before and after supplementation, subjects performed a maximal multistage discontinuous incremental running test to exhaustion. No significant differences in endurance capacity were observed between the creatine and placebo groups. Ostojic et al. (2004) examined the effects of a seven-day creatine supplementation (30 g/day) vs. placebo (cellulose) on endurance capacity assessed by a maximal multistage 20 m shuttle run test in 20 young soccer players in a randomised parallel study. No significant differences between the creatine and placebo groups
were observed. In the study by Zoeller et al. (2007), 55 men (24.5 5.3 years) were randomly assigned to one of the following supplementation groups for four weeks: placebo (34 g glucose/day, n=13), creatine (5.25 g/day creatine monohydrate plus 34 g glucose, n=12), beta-alanine (n=14), or beta- alanine plus creatine (n=16). Prior to and following supplementation, participants performed a graded exercise test on a cycle ergometer to determine time to exhaustion. The initial power output was set at 30 watts and increased 30 watts every two minutes until the subject could not maintain the required power output at a pedaling rate of 70 rpm, or until volitional termination owing to fatigue. No significant differences in time to exhaustion were observed between groups.
The Panel notes that the three human intervention studies provided did not show an effect of creatine supplementation on measures of endurance capacity. The Panel also notes that there is no consensus on the role of creatine in increasing endurance (aerobic) capacity (AFSSA, 2000; Buford et al., 2007; Kreider et al., 2010; SCF, 2001; Terjung et al., 2000).
In weighing the evidence, the Panel took into account that the three human intervention studies provided from which conclusions could be drawn for the scientific substantiation of the claim did not show an effect of creatine supplementation on measures of endurance capacity.
The Panel concludes that a cause and effect relationship has not been established between the consumption of creatine and an increase in endurance capacity.

Warunki i możliwe ograniczenia stosowania oświadczenia

The product must contain at least 5 gram creatine per serving Claim to be used for foods for active individuals

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