Black tea and maintenance of normal endothelium-dependent vasodilation

Health claim: Black tea and maintenance of normal endothelium-dependent vasodilation

Following an application from Unilever NV, submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Ireland, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to black tea and maintenance of normal endothelium-dependent vasodilation.

The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence.

The general approach of the NDA Panel for the evaluation of health claims applications is outlined in the EFSA general guidance for stakeholders on health claim applications and the guidance on the scientific requirements for health claims related to antioxidants, oxidative damage and cardiovascular health.

The food proposed by the applicant as the subject of the health claim is black tea beverages, either freshly prepared or reconstituted from water extract powders of black tea, characterised by the content of flavanols (expressed as catechins plus theaflavins) of at least 30 mg per 200 mL serving. The Panel considers that black tea characterised by the content of flavanols (expressed as catechins plus theaflavins) of ≥ 30 mg/200 mL serving, which is the subject of the health claim, is sufficiently characterised.

The claimed effect proposed by the applicant is ‘improvement of endothelium-dependent vasodilation’. The proposed target population is ‘adults in the general population’. The Panel considers that maintenance of normal endothelium-dependent vasodilation is a beneficial physiological effect.

The applicant identified as directly pertinent to the claim five human intervention studies on the effect of black tea consumption on endothelium-dependent vasodilation measured in fasting conditions after regular consumption of black tea (chronic effect) and four human intervention studies on the acute effect of black tea consumption on endothelium-dependent vasodilation after regular consumption of black tea (acute-in-chronic effect). In addition, the applicant provided eight human intervention studies on the acute effects of tea beverages on endothelium-dependent vasodilation as supportive evidence. The applicant also submitted meta-analyses of the chronic, acute-in-chronic studies and acute studies, both individually and combined.

Out of the five human intervention studies provided on the chronic effect of black tea consumption on endothelium-dependent vasodilation, only two investigated the effect after regular consumption of black tea for a sufficiently long time period (i.e. at least four weeks).

In one of these studies, an effect of black tea consumption not only on endothelium-dependent vasodilation but also on endothelium-independent vasodilation was observed. Therefore, this study did not allow conclusions to be drawn on whether the effects of black tea consumption on vasodilation were endothelium dependent or mediated via endothelium-independent pathways. The Panel considers that no conclusions can be drawn from this study on the effect of black tea consumption on endothelium-dependent vasodilation. The second study in which black tea was consumed for 6 months did not show an effect of black tea consumption on endothelium-dependent vasodilation.

In the absence of studies allowing an effect of black tea consumption to be established on endothelium-dependent vasodilation in fasting conditions in healthy individuals after regular consumption of the food for at least 4 weeks, the Panel considered that studies of shorter duration, on an acute effect of black tea consumption with or without preceding continued consumption of the food, or in patients, as well as the meta-analysis provided by the applicant cannot be used for the scientific substantiation of the claim.

In weighing the evidence, the Panel took into account that the two studies which were provided by the applicant and which investigated the effect of black tea consumption on endothelium-dependent flow-mediated dilation in fasting conditions after regular consumption of the food for at least four weeks did not allow an effect of black tea on endothelium-dependent vasodilation to be established.

On the basis of the data provided, the Panel concludes that a cause and effect relationship has not been established between the consumption of black tea and maintenance of normal endothelium-dependent vasodilation.

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Ria Van Hoef