ID 1708 -
Galusan epigallokatechiny z herbaty
PL: Galusan epigallokatechiny z herbaty
EN: Epigallo-catechin-3-gallate (EGCG) / Green tea extract, rich in EGCG
Pdf: Camellia sinensis
Oświadczenie (2)
- ochrona tkanek i komórek przed uszkodzeniem oksydacyjnym
- przeciwutleniacz
- naturalnym przeciwutleniaczem
1. Charakterystyka żywności / składnika
The food constituent that is the subject of the health claims is Camellia sinensis (L.) Kuntze, catechins present in green tea, and epigallo-catechin-3-gallate.
In the wording of claim ID 1105, tannins and fluoride are named as active ingredients in tea in relation to a claimed effect on oral health. The Panel refers to its previous opinion on fluoride in the context of the evaluation of Article 13 claims (EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), 2009); the effects of fluoride (irrespective of the source) on tooth mineralisation will not be considered further in this Opinion.
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 levels 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 level of fermentation, the production process, and the method for 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) and tannins in black tea (mainly theaflavin and thearubigin) 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 in green tea (including EGCG) and tannins in black tea (for ID 1105) are sufficiently characterised.
2.1. Ochrona DNA, białek i lipidów przed uszkodzeniem oksydacyjnym (ID 1103, 1276, 1311, 1708, 2664)
The claimed effects are “antioxidant”, “natural antioxidant” and “protection of body tissues and cells from oxidative damage”. 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 relate to the protection of body cells and molecules from oxidative damage caused by free radicals.
Reactive oxygen species (ROS) including several kinds of radicals are generated in biochemical processes (e.g. respiratory chain) and as a consequence of exposure to exogenous factors (e.g. radiation, pollutants). These reactive intermediates damage biologically relevant molecules such as DNA, proteins and lipids if they are not intercepted by the antioxidant network which includes free radical scavengers like antioxidant nutrients.
The Panel considers that protection of DNA, proteins and lipids from oxidative damage may be a beneficial physiological effect.
3.1. Ochrona DNA, białek i lipidów przed uszkodzeniem oksydacyjnym (ID 1103, 1276, 1311, 1708, 2664)
The vast majority of references provided in the list addressed other topics than Camellia sinensis (L.) Kuntze (tea) or green tea catechins, the claimed effect, or the relationship between the intake of tea/green tea catechins and the claimed effect. These include narrative reviews on polyphenols in general, in vitro testing of the antioxidant properties of different foods, compositional analyses, and
human studies investigating the effects of green tea catechins/polyphenols on cholesterol lowering, cancer prevention, photoprotection, or have been conducted in different patient populations aiming at secondary prevention or at treatment of disease conditions. The Panel considers that no scientific conclusions can be drawn from these references to substantiate the claims.
Some experimental, and generally small-scale, human studies reported that green tea or catechins in green tea are able to increase the total antioxidant activity of plasma measured by various assays including ferric reducing ability of plasma (FRAP), oxygen radical absorbance capacity (ORAC), trolox-equivalent antioxidant capacity (TEAC), and total reactive antioxidant potential (TRAP) (van Amelsvoort et al., 2001; Benzie et al., 1999; Coimbra et al., 2006; Leenen et al., 2000; Pietta et al., 1998; Serafini et al., 1996; Sung et al., 2000), to reduce the formation of malondialdehyde (colorimetric assay) (Coimbra et al., 2006), to increase the oxidation lag time of LDL ex vivo (Luo et al., 1997; van het Hof et al., 1997; Hodgson et al., 2000; Serafini et al., 2000; Ohmori et al., 2005), and to decrease DNA damage to lymphocytes measured by the comet assay (challenging with Fe2+
before electrophoresis) (Erba et al., 2005). The Panel notes that measurements of the total antioxidant activity/potential of plasma are not considered to be markers of oxidative damage, and that the formation of malondialdehyde using a colorimetric assay as well as the resistance of LDL to oxidation are not suitable markers to assess lipid peroxidation (Griffiths et al., 2002; Mayne, 2003; Dalle-Donne et al., 2006; Knasmüller et al., 2008; Dragsted, 2008). The Panel also notes that the variant of the comet assay used in the study by Erba et al. (2005) does not specifically measure DNA oxidative damage but general DNA damage independent of its origin. The Panel considers that no scientific conclusions can be drawn from these studies for the substantiation of the claimed effect.
Two randomised controlled human intervention studies (Hakim et al., 2003; Young et al., 2002) investigated the effects of green tea catechin intake on measures of oxidative damage to DNA and one acute study (Nakagawa et al., 1999) investigated the effects of green tea catechin intake on measures of oxidative damage to body lipids.
In a two times three week blinded human crossover intervention study, volunteers (eight smokers, eight non-smokers, aged 20-31 years) consumed green tea extract (18.8 mg catechins per day) incorporated into meat patties (meat patties without catechins used as control). The intervention did not significantly affect plasma oxidation lag time or urinary 8-OHdG assessed by HPLC-ECD (Young et al., 2002). The Panel notes that the evidence provided does not establish that urinary 8-OHdG reflects oxidised DNA within cells (Cooke et al., 2009).
A total of 143 heavy smokers (aged 18-79 years) were randomised to drink 4 cups per day of either decaffeinated green tea (73.5 mg/cup total catechins), decaffeinated black tea (8.11 mg/cup total catechins) or water during four months (Hakim et al., 2003). Among the 133 smokers who completed the intervention, drinking green tea resulted in a significant decrease in urinary 8-OHdG assessed by ELISA (-31%) compared with water, while no significant change was observed among smokers consuming black tea. The Panel notes that the evidence provided does not establish that urinary 8- OHdG reflects oxidised DNA within cells (Cooke et al., 2009).
The effect of green tea extract (254 mg total catechins/subject) on plasma phosphatidylcholine hydroperoxides (PCOOH by HPLC-CL) was investigated in an acute study with 18 healthy male volunteers (Nakagawa et al., 1999). The Panel notes that, although changes in plasma PCOOH measured by HPLC-CL is an acceptable marker of lipid peroxidation, no conclusions can be drawn from this study in relation to a sustained effect of green tea catechins on lipid peroxidation.
The Panel notes that no studies with appropriate endpoints to assess oxidative damage of DNA within cells or studies investigating a sustained effect of green tea catechins on lipid peroxidation have been presented to substantiate the claimed effect. The Panel also notes that no studies investigating the effect of green tea catechins on oxidative damage to proteins have been presented.
The Panel concludes that a cause and effect relationship has not been established between the consumption of catechins (including EGCG) in green tea (Camellia sinensis (L.) Kuntze) and the protection of DNA, proteins or lipids from oxidative damage.
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