ID 4663 -
Chitozan
PL: Chitozan
EN: Chitosan
Pdf: chitosan
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claim is chitosan.
Chitosan is a linear cationic polysaccharide composed of randomly distributed -(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine produced commercially by the deacetylation of chitin, which is a component of the exoskeleton of crustaceans and the cell walls of fungi. The degree of deacetylation can be measured by established methods, and ranges from 60-100 % in commercial preparations. The molecular weight of chitosan in commercial preparations ranges from 3,800 to 20,000 Da. Chitosan is insoluble in water.
The Panel considers that the food constituent, chitosan, which is the subject of the health claims, is sufficiently characterised.
2.2. Utrzymanie prawidłowego stężenia cholesterolu LDL we krwi (ID 4663)
The claimed effect is “stimulates the regulation of cholesterol levels due to O-carboxymethyl chitosan”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effect relates to the maintenance of normal blood LDL-cholesterol concentrations.
Low-density lipoproteins (LDL) carry cholesterol from the liver to peripheral tissues, including the arteries. Elevated LDL-cholesterol, by convention >160 mg/dL (>4.14 mmol/L), may compromise the normal structure and function of the arteries.
The Panel considers that maintenance of normal blood LDL-cholesterol concentrations is a beneficial physiological effect.
3.2. Utrzymanie prawidłowego stężenia cholesterolu LDL we krwi (ID 4663)
Five animal studies and one human intervention study on the effects of chitosan on blood lipids were provided for the scientific substantiation of the claim.
The Cochrane systematic review (Jull et al., 2008) cited in section 3.1. also reported on the effects of chitosan on blood lipids and included the only human intervention study submitted for the scientific substantiation of the claim (Macchi, 1996).
Statistical analyses combining the nine trials that provided data on total cholesterol concentrations (Colombo and Sciutto, 1996; Ho et al., 2001; Kaats et al., 2006; Macchi, 1996; Ni Mhurchu et al., 2004; Pittler et al., 1999; Veneroni et al., 1996; Wuolijoki et al., 1999; Zahorska-Markiewicz et al., 2002) were reported in the meta-analysis. However, the Panel notes that some of these studies used treatment preparations which contained other active ingredients in addition to chitosan, and considers that no conclusions can be drawn from these analyses for the scientific substantiation of the claim. When the trials were limited to those that used chitosan alone as intervention (Ho et al., 2001; Macchi, 1996; Ni Mhurchu et al., 2004; Pittler et al., 1999; Zahorska-Markiewicz et al., 2002), a small but statistically significant reduction in total cholesterol concentrations of -0.15 mmol/L (95 % CI -0.23 to -0.07, p=0.0002) was observed. Similar results were obtained when the analyses were limited to trials that met the allocation concealment quality criteria (Ni Mhurchu et al., 2004; Pittler et al., 1999) (-0.15 mmol/L; 95 % CI -0.23 to -0.07, p=0.0004). The I2-statistic indicated substantial heterogeneity (I2=59.5 %).
Statistical analyses combining the seven trials that included data on LDL-cholesterol concentrations (Colombo and Sciutto, 1996; Ho et al., 2001; Kaats et al., 2006; Ni Mhurchu et al., 2004; Veneroni et al., 1996; Wuolijoki et al., 1999; Zahorska-Markiewicz et al., 2002) were provided in the meta-analysis. However, the Panel notes that four of these trials used treatment preparations which contained other active ingredients in addition to chitosan (Colombo and Sciutto, 1996; Kaats et al., 2006; Veneroni et al., 1996; Wuolijoki et al., 1999), and that no separate analysis of the trials using chitosan alone was provided. The Panel notes, however, that whereas the studies by Ho et al. (2001) and Zahorska-Markiewicz et al. (2002), including 68 and 32 subjects respectively, did not show a significant effect on LDL-cholesterol concentrations, the largest study, by Ni Mhurchu et al. (2004), which included 250 subjects (125 per group), observed a small but statistically significant reduction in LDL-cholesterol concentrations in favour of chitosan (-0.12 mmol/L, 95 % CI -0.19 to -0.05). Similar results were obtained when the analysis was limited to the two studies of 6 months duration (-0.14 mmol/L, 95 % CI -0.19 to -0.06) (Ni Mhurchu et al., 2004; Zahorska-Markiewicz et al., 2002).
Statistical analyses combining the seven trials that provided data on HDL-cholesterol concentrations (Colombo and Sciutto, 1996; Ho et al., 2001; Kaats et al., 2006; Macchi, 1996; Ni Mhurchu et al., 2004; Veneroni et al., 1996; Zahorska-Markiewicz et al., 2002) were also provided. The Panel notes that three of these trials used treatment preparations which contained other active ingredients in addition to chitosan (Colombo and Sciutto, 1996; Kaats et al., 2006; Veneroni et al., 1996), and that no separate analysis of the trials using chitosan alone was provided in the meta-analysis. The Panel also notes that only the smallest study using chitosan alone showed a statistically significant increase in HDL-cholesterol concentrations compared to placebo (0.15 mmol/L, 95 % CI 0.03 to 0.27; 10 subjects per group) (Macchi, 1996), whereas no significant differences between chitosan and
placebo were observed in any of the other three studies, including the largest study by NiMhurchu et al. (2004), which had the longest duration (6 months).
The Panel notes that while chitosan consumption at doses of about 3 g/day showed, in the meta- analysis by Jull et al. (2008), a small but statistically significant effect on the reduction of both total (combining five studies) and LDL-cholesterol (combining two studies) concentrations, no effect was observed on HDL-cholesterol concentrations.
The mechanism by which chitosan is presumed to exert the claimed effect is by binding to negatively charged lipids and hence reducing their gastro-intestinal uptake, and these effects were observed in some animal studies (Deuchi et al., 1995; Sugano et al., 1980; Zacour et al., 1992). The effects of chitosan on 24 h faecal fat excretion in healthy human volunteers at doses of about 3 g daily were not statistically significant (Guerciolini et al., 2001), and it is unclear whether this could play a role on the claimed effect.
In weighing the evidence, the Panel took into account that a meta-analysis of RCTs, which investigated the effects of chitosan consumption on blood lipids, showed a small but statistically significant reduction in total and LDL-cholesterol concentrations.
The Panel concludes that a cause and effect relationship has been established between the consumption of chitosan and maintenance of normal blood LDL-cholesterol concentrations.
4.1. Utrzymanie prawidłowego stężenia cholesterolu we krwi (ID 4663)
The Panel considers that the following wording reflects the scientific evidence: “Chitosan may contribute to maintaining normal blood cholesterol levels”.
5.1. Utrzymanie prawidłowego stężenia cholesterolu we krwi (ID 4663)
The Panel considers that in order to obtain the claimed effect, 3 g of chitosan should be consumed daily. The target population is adults.
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