Flow Mediated Dilation in Response to Black Tea

Flow Mediated Dilation in Response to Consumption of Black Tea Versus Artificial Tea, in Non-tea Drinking Hypertensive Subjects.

Research indicate that people who regularly drink tea have a reduced risk of stroke or heart disease. In a number of studies in which people that normally do not drink showed that their blood vessels function improved when the drunk tea. The current study tests whether a specific black tea improves vessel function in non-tea drinking hypertensive subjects.

Epidemiological studies indicate that regular consumption of three cups of black tea per day reduces the risk of stroke or myocardial infarction. In a number of previous nutrition intervention studies tea has been shown to improve vascular function as assessed by Flow Mediated Dilation in various populations. The current confirmatory study tests a specific black tea against a placebo in a population of in non-tea drinking hypertensive subjects.

Inclusion Criteria:

• Males and post menopausal (> 1 year) females, not on hormone replacement therapy

• Aged >18 and < 65 years

• Body mass index (BMI) of >=18.0 and =<35.0 kg/m2

• Hypertension as previously diagnosed by primary care or hospital physician.

  • If untreated, office BP between 140/90 mmHg and 160/100 mmHg on screening
  • If treated, a controlled blood pressure (<160/100) on stable medication for at least 4 weeks

Exclusion Criteria:

• Tea drinkers: having typically consumed > 1 cup of black tea per week.
• Current smoker or has stopped smoking less than 6 months before start of study
• Self reported alcohol intake of >21 units/week
• Established cardiovascular disease other than hypertension
• Clinically significant arrhythmia
• Diabetes mellitus
• Chronic Kidney Disease > stage 2
• 10-year cardiovascular risk equivalent to 20% or greater using the QRisk2 calculator
• Abnormality of laboratory blood tests considered clinically significant
• Any other significant intercurrent condition/disease