Using a cohort of 19 healthy men (mean age 33), the researchers assigned participants to one of five prescribed intakes of black tea over five periods lasting one week each. The caffeine level of each dose was standardized but the dose of tea flavonoids was controlled at levels of 0 (the control dose), 100, 200, 400 and 800 mg of tea flavonoids per day. A standard cup of black tea contains approximately 100-200 mg of flavonoids, depending on the individual preference of tea making. During the duration of the study, participants avoided naturally flavonoid-rich food and beverages such as red wine and chocolate to ensure that the results were a true reflection of flavonoid-rich black tea consumption only.
"In our study, black tea affected vascular function in normal individuals. We observed that vascular function improvement exerted by black tea started with one cup per day and further improved by increasing the number of daily cups of tea," explained Professor
"We used the gold standard technique to assess the dilation of the brachial artery in response to black tea and observed a significant improvement in arterial dilation. Simultaneously, we also observed that black tea consumption lowered blood pressure and reduced arterial rigidity, thereby improving the elastic capacity of the blood vessels."
"Maintaining vascular function, with drinking even a single cup of black tea suggests that black tea may help maintain healthy cardiovascular function in common tea drinkers. Further studies are needed to evaluate longer-term effects in different populations."
"We are delighted to have helped fund this study and helped further our understanding of the role of tea in health and wellness – and particularly its potential to help maintain cardiovascular health. This new study provides further support that regular tea drinking may be one of the most actionable changes a consumer can make as part of a healthy lifestyle."
Tea is the second most consumed drink in the world after water, and is a major source of dietary flavonoid intake in Western countries and in the Middle and Far East. Although this study evaluated a limited population – healthy men – and further research is needed, its findings may ultimately be relevant to millions of tea drinkers globally.
A full copy of the research findings, Black tea consumption dose-dependently improved flow-mediated dilation in healthy males, will be published in The Journal of Hypertension in
More information on this research, including a copy of the original research paper, and details on the Lipton Institute of Tea can be obtained by contacting
About the Lipton Institute of Tea
The Lipton Institute of Tea is Unilever's dedicated tea research facility, headquartered at Sharnbrook, just outside
The Lipton Institute of Tea publishes regular academic papers, aimed at uncovering and sharing the physical and mental health properties of tea. It is responsible for publishing The Lipton Institute of Tea Quarterly Tea Science Review, a quarterly overview of key tea science research developments from both internal and external sources and compiled to share recent studies and findings to a broader, non-specialist audience.
The Lipton Institute of Tea also operates the world's most northerly tea 'plantation' at its Sharnbrook headquarters. This facility enables tea to be studied in a controlled environment, as representative samples of tea from around the world are grown. Here, the journey from bush to cup – through drying and processing – can be very much shorter than usual.
More information on the Lipton Institute of Tea can be found at: www.liptoninstituteoftea.org
SOURCE Lipton Institute of Tea