ID 731 -
Sprzężony kwas linolowy
PL: Sprzężony kwas linolowy
EN: CLA (Conjugated linoleic acid)
Pdf: conjugated linoleic acid
Oświadczenie (2)
- obsługuje beztłuszczowej masy ciała
1. Charakterystyka żywności / składnika
The food that is the subject of the health claim is conjugated linoleic acid (CLA).
CLA refers to a group of positional and geometric isomers of linoleic acid that are characterised by the presence of conjugated dienes. CLA is a natural, but minor, component of fats from ruminant animals present in the human diet primarily in meat and dairy products. In nature, the most abundant isomer is cis-9, trans-11 (c9, t11), whereas in supplement forms CLA is typically sold as an equal mix of the two predominant isomers c9, t11 and t10, c12. Different isomers may have different effects.
The majority of the human intervention studies provided for the scientific substantiation of the health claims have used equimolar combinations of the c9, t11 and t10, c12 isomers, and therefore the Panel assumes that the food, which is the subject of the health claims, is an equimolar mixture of the CLA isomers c9, t11 and t10, c12
The Panel considers that the food constituent, an equimolar mixture of the conjugated linoleic acid (CLA) isomers c9, t11 and t10, c12, which is the subject of the health claims, is sufficiently characterised.
2.2. Zwiększenie beztłuszczowej masy ciała (ID 498, 731)
The claimed effect is “supports lean body mass”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings and clarifications provided by Member States, the Panel assumes that the claimed effect refers to an increase in lean body mass.
The Panel considers that an increase in lean body mass is a beneficial physiological effect.
3.2. Zwiększenie beztłuszczowej masy ciała (ID 498, 731)
Most of the randomised, placebo-controlled trials (RCTs) which investigated the effects of CLA supplementation on body composition in humans that were cited in the consolidated list were included in the meta-analysis by Whigham et al. (2007). One RCT not included in the meta-analysis was also considered by the Panel as pertinent to this claim (Steck et al., 2007). An additional study by Lowery et al. (1998) was available only in abstract form, and could not be fully evaluated by the Panel in relation to the claimed effect.
Among the 15 weight loss RCTs considered in the meta-analysis by Whigham et al. (2007) described in section 3.1, which used an equimolar mixture of the CLA isomers c9, t11 and t10, c12, three did not report on changes in lean body mass (Mougios et al., 2001; Smedman and Vessby, 2001; Atkinson, 1999) and nine did not find statistically significant differences between the CLA and control groups in lean body mass changes (Berven et., al., 2000; Eyjolfson et al., 2004; Lambert et al., 2007; Malpuech-Brugere et al., 2004; Petridou et al., 2003; Riserus et al., 2002; Taylor et al., 2006; Gaullier et al., 2007; Watras et al., 2007), whereas three reported an effect of CLA intake on lean body mass during weight loss (Blankson et al., 2000; Gaullier et al., 2004; Pinkoski et al., 2006) in addition to the study by Steck et al. (2007). In the studies by Blankson et al. (2000) and Steck et al. (2007), a significant effect of CLA on lean body mass was observed only at the highest doses of CLA administered (6.8g per day and 6.4g per day of an equal mixture of the c9, t11 and t10, c12 CLA isomers, respectively). The Panel notes that these daily doses of CLA are about twice the doses proposed in the conditions of use. The Panel also notes that in the study by Gaullier et al. (2004), the effect was only significant when 3.4 g per day of the CLA isomers, an equal mixture of the c9, t11 and t10, c12 isomers, were given as free fatty acids (FFA), but not as triacylglycerols. In addition, only one (Kamphuis et al., 2003) out of the three studies (Kamphuis et al., 2003; Larsen et al., 2006; Whigham et al., 2004) which investigated the effects of CLA supplementation on body composition showed an effect in preserving lean body mass after weight loss independent of physical activity.
The two RCTs with the largest sample size per intervention group and which used appropriate methods to assess body composition and appropriate duration (at least 12 weeks) under the proposed conditions of use (using up to about 3.4g per day of the CLA equimolar mixture) were considered further by the Panel (Gaullier et al., 2004, 2007).
The 108 subjects who participated in the RCT by Gaullier et al. (2004) were selected on the basis of being overweight (BMI 25–30 kg/m2, age range 18–65 years) and were randomly assigned to consume either 4.5 g olive oil (placebo, n=59, 47 women), 4.5 g 80 % CLA in the FFA form (3.6 g active CLA isomers, equal mixture of the c9, t11 and t10, c12, n= 61, 51 women), or 4.5 g 76 % CLA in the triacylglycerol form (3.4 g active CLA isomers, n=60, 51 women) per day for 12 months. Body composition was measured by dual-energy x-ray absorptiometry (DXA). A significant increase in lean body mass was observed only in the CLA-FFA group compared to placebo. No significant differences were observed between the two CLA groups regarding changes in lean body mass during the study. No evidence has been provided to establish that CLA administered as triacylglycerols or as FFA could have differential effects on changes in lean body mass.
The 115 subjects, who participated in another RCT by Gaullier et al. (2007), were selected on the basis of being overweight and obese (BMI 28–32 kg/m2, age range 18–65 years) and were randomised to consume either 3.4 g per day of the c9, t11 and t10, c12 CLA mixture or placebo (4.5 g per day olive oil) for 6 months. Whether the CLA supplement was administered in the FFA form or in the triacylglycerol form was not reported. A total of 105 (84 women) completed the intervention (n=55 in the CLA group), 83 of them with >70 % pill count compliance. No significant changes in lean body mass were observed in the CLA group as compared to placebo in completers or in the subgroup of subjects who reported good compliance.
The Panel notes that the studies by Gaullier et al. (2004, 2007) had similar design and sample size, used the same dose of the CLA equimolar mixture and the same method to assess changes in body composition (dual-energy x-ray absorptiometry), but lead to conflicting results regarding the effects of CLA consumption on lean body mass.
In weighing the evidence, the Panel took into account that most of the human studies provided did not observe a significant effect of CLA consumption on lean body mass, and that results from the studies with the largest sample size per intervention group, which used appropriate methods to assess changes in body composition and had an appropriate duration under the proposed conditions of use, are inconsistent with respect to the effects of consumption of an equimolar mixture of the CLA isomers c9, t11 and t10, c12 on lean body mass.
The Panel concludes that a cause and effect relationship has not been established between the consumption of an equimolar mixture of the CLA isomers c9, t11 and t10, c12 and an increase in lean body mass.
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