Tea’s positive impact on blood pressure confirmed in new systematic review
A new state of the art review has confirmed the positive impact of regular long-term tea consumption on blood pressure and evaluated the range of mechanisms by which this positive impact occurs.
Commenting on the research, Dr Tim Bond from the Tea Advisory Panel (www.teaadvisorypanel.com) notes: “Conducted by researchers in the United States and China, who included several meta-analyses in their paper, this review concluded that consumption of green tea significantly reduced both systolic blood and diastolic blood pressure by around 2 mmHg with a greater reduction in both systolic and diastolic blood pressure in study participants with higher blood pressure (>130mm Hg).
“Black tea, which remains the most popular type of tea in Britain, also showed a systolic and diastolic blood pressure lowering effect of almost 2mm Hg and 1.5 mm Hg respectively for green and black tea consumption respectively across the meta-analyses evaluated by the reviewers. Greater blood pressure lowering effects were seen in people with higher blood pressure.
“The review also considered some single large intervention trials, which again showed the blood pressure lowering effects of green and black tea and found that those who drank two and a half cups of green tea had a 65% reduced risk of developing high blood pressure compared with non-tea drinkers. A further single intervention trial evaluated in the review showed that regular consumption of three cups/day of black tea over six months, supplying approximately 429 mg/day of polyphenols, resulted in reductions in systolic and diastolic blood pressure of between 2 and 3 mmHg. “
Clinician, practitioner and an advisor to TAP, Dr Chris Etheridge adds: “Blood pressure lowering effects were found for a variety of people, including healthy population groups, as well as those of us ageing and people with diabetes and/or obesity.
“With regard to mechanisms, this review confirmed the blood pressure lowering effect of tea’s key ingredients including polyphenols, such as catechins and theanine. The underlying mechanisms for tea’s impact on blood pressure, shown in laboratory studies, include various beneficial effects on the blood vessels including relaxing smooth muscle contraction in the blood vessels, enhancing endothelial nitric oxide synthase activity, reducing vascular inflammation, inhibiting renin activity, and reducing anti-vascular oxidative stress.
“Overall this review confirms research that has been continually emerging for some years – that both black and green tea consumed regularly and in the long term can lower blood pressure in healthy people and in those with conditions such as diabetes.”