Effect of black tea consumption on flow mediated dilatation: a randomized, placebo controlled, double blind, crossover trial

INTERVENTION: FMD analysis and blood sampling is carried out before intake of black tea, 2 and 4 hours after intake of drink FMD analysis and blood sampling is carried out before intake of placebo drink, 2 and 4 hours after intake of drink CONDITION: Healthy volunteers PRIMARY OUTCOME: FMD SECONDARY OUTCOME: Blood Nitrate/Nitrite concentration; Blood catechole amine concentration INCLUSION CRITERIA: 1) Subjects aged 20 through 65 years 2) Subjects whose systolic blood pressure below 150 mmHg 3) Subjects who have not taken alcohol drink the day before 4) Subjects are competent to consent