Washington, Jan 25: Drink at least three cups of black tea daily to help lower your blood pressure, scientists have claimed.
Researchers at the University of Western Australia found that people who drank three cups of black tea a day managed to lower their blood pressure (BP) levels by an average of two to three points.
That may not sound like much, but even small reductions in BP levels can have a major impact on the prevalence of high blood pressure (hypertension) and risk of heart disease, the researchers said.
“At a population level, the observed differences in BP would be associated with a 10 per cent reduction in the prevalence of hypertension and a seven per cent to 10 per cent reduction in the risk of heart disease and stroke,” study author Jonathan Hodgson was quoted as saying by WebMD.
In the study, the researchers looked at the effect of black tea on blood pressure levels among 95 men and women who were regular tea drinkers.
Their average systolic blood pressure (the top number in a blood pressure reading) was between 115 and 150 at the start of the study.
Half of the participants drank three cups of black tea per day for six months, and the other half drank a placebo drink with a similar flavour and caffeine content. Both groups were similar in terms of gender, age, and weight status.
By the end of the study, those who drank black tea experienced an average reduction of between two and three points in their 24-hour average systolic blood pressure level and about two points in their diastolic (the lower number in a blood pressure reading) level.
This is the first time that long-term use of black tea has been shown to lower blood pressure in people with normal to high-normal blood pressure, said the researchers who detailed their finding in the Archives of Internal Medicine.
According to the researchers, there are a number of potential explanations for this health benefit.
Recent studies have shown that drinking black tea can improve the function of the endothelial cells, which line the interior of blood vessels. Endothelial dysfunction is an early indicator of blood pressure changes.
Other research has suggested that the flavonoids found in tea can improve the blood vessel's tone and reduce body weight and abdominal fat.
These findings have important public health implications in light of the high rates of high blood pressure worldwide and the importance of high blood pressure as a risk factor for heart disease and death, the researchers added.