Green tea is already popular worldwide because of its immensely powerful health benefits. Now a Greek team has found that a cup of the bru daily helps in expanding arteries, which in turn improves blood flow thereby keeping the heart healthy.

According to researchers, the flavonoids in green tea relax the cells, called the endothelium, which is a thin layer on the inside of the blood vessels, that smooths the flow of blood allowing a more efficient circulation.

"Tea consumption has been associated with reduced cardiovascular morbidity and mortality in several studies. Green tea is consumed less in the Western world than black tea, but it could be more beneficial because of the way it seems to improve endothelial function.

"In this same context, recent studies have also shown potent anticarcinogenic effects of green tea attributed to its antioxidant properties," lead researcher Nikolaos Alexopoulos was quoted by the British media as saying.

In their study, the researchers at Athens Medical School tested a small group of volunteers who consumed green tea, 125 mg of caffeine and 450 ml of hot water on three separate occasions.

The team measured the diameter of the brachial artery in each participant 30, 90 and 120 minutes after they consumed each beverage. Dilation of the artery peaked at an increase of 3.9 per cent at the 30-minute test time.

They found that the caffeine and hot water did not have the same effect on the brachial artery that the green tea did -- in fact, drinking six grams of the drink caused the participants' brachial arteries (in the upper arm) to expand by almost four per cent.