A six month study by scientists at the University of Western Australia (UWA), Unilever, and the National Health and Medical Research Council of Australia shows that people who drink black tea throughout the day may get the benefit of a slight reduction in their blood pressure. The study is published in the Archives of Internal Medicine.
In the study, 95 Australian participants ages 35–75 were recruited to drink either three cups of black tea or another beverage similar in taste and caffeine content, but not derived from tea, daily for six months. Before the study started, the participants’ blood pressure throughout the day was about 121/72 millimeters of mercury (mm Hg). Blood pressure readings less than or equal to 120/180 mm Hg are considered normal.
After the six-month period, the research found that the tea drinkers’ systolic (top number) and diastolic (bottom number) blood pressure fell between 2–3 mm Hg compared to non-tea drinkers. More research is required to better understand how tea may reduce blood pressure, although earlier studies reported a potential link between tea consumption and the improved health of people’s blood vessels.