A new study conducted at the University of L’Aquila, Italy, and supported by the Lipton Institute of Tea, is the first to show that black tea consumption – depending on dose – simultaneously increased blood vessel reactivity and reduced both blood pressure and arterial stiffness, suggesting a cardiovascular health profile that is consistent with maintaining heart health.
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 standardised but the dose of tea flavonoids was controlled at levels of 0 (the control dose), 100, 200, 400 and 800mg 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 Claudio Ferri, the principle investigator of the study. “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.”
Dr Douglas Balentine, Research Director at the Lipton Institute of Tea, added, “In recent years, a growing volume of scientific research has suggested that, as part of a healthy lifestyle, regular tea drinking may help maintain a healthy heart. In this new study, tea flavonoids appeared to play a role in maintaining healthy blood vessel function, which in turn could contribute to maintaining cardiovascular health. The study’s results showing improved vascular function are also consistent with factors that could account for the results of a recent analysis in which regular tea drinking was associated with a significantly reduced risk of ischaemic stroke.”
“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 “Black tea consumption dose-dependently improved flow-mediated dilation in healthy males” findings will be published in The Journal of Hypertension this month.