ID 1112 - Katechiny z zielonej herbaty

PL: Katechiny z zielonej herbaty
EN: Catechins – Green tea (camellia sinensis)
Pdf: Camellia sinensis

Oświadczenie (2)

1. Charakterystyka żywności / składnika

The food/constituents that are the subjects of the health claims are Camellia sinensis (L.) Kuntze, catechins present in green tea, epigallo-catechin-3-gallate (EGCG) and green tea extract rich in EGCG.
The plant Camellia sinensis (L.) Kuntze is an evergreen shrub of the Theaceae family. Tea is an extract of the dried leaves from Camellia sinensis (L.) Kuntze and it is usually prepared by infusing the leaves in hot water. The composition of the tea leaves depends on a variety of factors, including climate, season, horticultural practices, and the type and age of the plant. Many kinds of tea are produced, which can be classified into three major types according to the different degrees of fermentation: green (un-fermented), oolong (semi-fermented) and black (fully fermented) (Wang et al., 2000).
The composition of tea beverages greatly depends on the type of leaves used, on the degree of fermentation and on the methods of preparation (Kaszkin et al., 2004; Astill et al., 2001). The degree of fermentation, the production process and the method of preparing the tea infusion have not been described in relation to the claims.
Green tea contains polyphenolic compounds, which include flavanols, flavandiols, flavonoids and phenolic acids. Most of the polyphenols in green tea are catechins. Epigallo-catechin-3-gallate (EGCG) is the most abundant catechin in green tea. In black teas, the most abundant polyphenols are tannins, mainly theaflavin and thearubigin (Mukhtar and Ahmad, 2000). Tea extracts/infusions also contain variable amounts of potentially active food constituents, such as caffeine, theanine or theogallin.
Green tea catechins (including EGCG) can be measured in foods by established methods.
The Panel considers that whereas Camellia sinensis (L.) Kuntze (tea) is not sufficiently characterised in relation to the claimed effects, catechins from green tea (including EGCG) are sufficiently characterised.

2.1. Udział w utrzymaniu lub osiągnięciu prawidłowej masy ciała (ID 1107, 1112, 1544, 2716)

The claimed effects are “weight management/metabolism of lipids”, “weight management” and “control of weight”. The Panel assumes that the target population is the general population.
In the context of the proposed wordings, the Panel assumes that the claimed effects refer to an increased oxidation of body fat leading to the loss of fat mass and body weight.
Weight management can be interpreted as contribution to the maintenance of a normal body weight. In this context a moderate weight loss in overweight subjects without achieving a normal body weight is considered to be a beneficial physiological effect.
The Panel considers that the contribution to the maintenance or achievement of a normal body weight is a beneficial physiological effect.

3.1. Udział w utrzymaniu lub osiągnięciu prawidłowej masy ciała (ID 1107, 1112, 1544)

A total of 48 references were cited in relation to the claimed effect. Twelve references were reviews on the mechanisms by which green tea catechins (GTCs) could exert the claimed effect, but provided no original data. Three references provided information on technological and quality aspects of green tea. Other references reported on the acute effects of green tea supplements on energy expenditure
and nutrient utilisation but did not report on body weight. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claimed effect.
Nine references provided data from human intervention studies on the effects of green tea catechins on weight management (Chan et al., 2006; Diepvens et al., 2006; Hase et al., 2001; Kovacs et al., 2004; Nagao et al., 2005, 2007; Takashi et al., 2002; Tsuchida et al., 2002; Westerterp-Plangtenga et al., 2005). The papers by Takashi et al. (2002) and Tsuchida et al. (2002) were published in the same Journal and the abstract contained the same information, so apparently referred to the same study.
All of these references with the exception of Takashi et al. (2002) have been considered in a recently published meta-analysis of randomised, double-blind, controlled trials (RCT) which investigated the effects of GTCs with or without caffeine on body weight (Phung et al., 2010).
A total of 15 trials (n=1,243) met the inclusion criteria for the meta-analysis by Phung et al. (2010). Of the 15 trials included, seven trials (n=600) evaluated GTCs with caffeine compared with a caffeine-matched control, six trials (n=524) evaluated GTCs with caffeine compared with a caffeine-free control, and two trials (n=119) evaluated caffeine-free GTCs compared with a caffeine-free control. The Panel notes that studies testing the effects of GTCs plus caffeine compared to a caffeine-free control do not allow conclusions to be drawn on the effects of GTCs alone because an interaction between GTCs and caffeine on the claimed effect cannot be excluded from the data provided. The Panel considers that no conclusions can be drawn from these studies or the meta- analysis by Phung et al. (2010) for the scientific substantiation of the claimed effect.
In a randomised, double-blind, placebo-controlled and parallel study, Takeshita et al. (2008) investigated the effects of GTCs on body weight in 81 healthy Japanese overweight and obese men (BMI≥25) who were randomly assigned to consume one bottle of sports drink per day containing decaffeinated green tea extract (548 mg GTC and 0 mg caffeine: catechin group, n=40), or one bottle of sports drink per day (0 mg of both GTCs and caffeine: placebo group, n=41) over 12 weeks. At the end of the study, body weight was significantly lower in the catechin group than in the placebo group. As only the abstract and tables in this publication were in English, and the full text was available in Japanese only, the Panel could not perform a complete evaluation of this study.
In a second randomised, double-blind, placebo-controlled and parallel study, Hill et al. (2007) randomised 42 overweight or obese post-menopausal women to consume either EGCG (300 mg/d) or placebo (lactose) twice daily for 12 weeks. Subjects were excluded if regular tea consumption exceeded three cups per day and/or habitual caffeine intake exceeded 300 mg per day. A total of 38 subjects completed the study (19 per group). Both groups were prescribed moderate physical exercise during the study (i.e. an exercise programme requiring running or walking for 45 minutes, three times per week at a heart rate which corresponded to 75 % of their age predicted maximum). No significant differences between groups were observed with respect to body weight changes
(0.08 kg 0.21 vs. -0.45 kg 0.27, in the intervention versus the placebo groups, respectively).
In weighing the evidence, the Panel took into account that the only intervention study from which sufficient information was available for a scientific evaluation found no effect of EGCG consumption on body weight.
The Panel concludes that a cause and effect relationship has not been established between the consumption of catechins (including EGCG) from green tea (Camellia sinensis (L.) Kuntze) and contribution to the maintenance or achievement of a normal body weight.

Warunki i możliwe ograniczenia stosowania oświadczenia

Recommended dosage 400-600 mg catechins Catechins are active and functional polyphenol components of green tea leaves. One cup (200ml) of brewed green tea may contain 100-150 mg of catechins.or equivalent of 50-60mg of EGCG. The usual consumption of green tea is about 5-10 cups per day, which is equivalent to 500-1200 mg of catechins or 250-600 mg of EGCG per day.