Drinking up to eight cups of tea a day lowers blood pressure and could prevent heart disease, Australian scientists have found.
Researchers at the University of Western Australia gave black leaf tea, such as Earl Grey or English Breakfast to volunteers with normal to high blood pressure.
They were given drinks containing 429 milligrams of the plant chemical polyphenols -- or the equivalent of eight and a half cups of tea a day.
A second group were given a tea-flavoured placebo.
After six months, the blood pressure of the tea-drinking group had fallen by between two and three mmHg, the measurement of pressure used in medicine.
A blood pressure fluctuating with the heartbeat between 112 and 63 mmHg is considered healthy, while a reading fluctuating between 140 and 90 is deemed high.
If the experiment was emulated by the general population, the number of people with high blood pressure would be cut by 10 percent and the risk of heart disease would fall by between seven and 10 percent.
"Our study has demonstrated for the first time to our knowledge that long-term regular consumption of black tea can result in significantly lower blood pressures in individuals with normal to high-normal range blood pressures," the team, led by Jonathan Hodgson, wrote in the journal Archives of Internal Medicine.
Adding milk to tea also does not affect the body's ability to absorb polyphenols, earlier studies have suggested.
Green tea is believed to have many health benefits as it is high in antioxidants. It is said to help in weight loss, prevent glaucoma and reduce risk of cancer.
