A US study by Harvard Medical School and Harvard School of Public Health in Boston of 83,000 women indicated that those that drink five to seven cups of coffee a week were 12% less likely to have a stroke than were those who have just one cup a month, according to a report published in the journal Circulation.

"The benefit does not appear to come from caffeine. Those who drank tea and other caffeinated drinks did not experience the same reduction in stroke risk," commented Professor Martin Grond of the German Stroke Society.

The benefits of drinking coffee are thought to originate from antioxidants in the beverage which lower inflammation and improve blood vessel function.

Taking into consideration factors such as cigarette and alcohol consumption, researchers found that healthy women who drank two to three cups of normal caffeinated coffee a day had, on average, a 19% lower risk for any kind of stroke than did women who drank less than one cup a month. Drinking four or more cups a day lowered the risk by 20%.

However, the study found that the beneficial effects of coffee only apply to otherwise healthy people. "Those with complaints such insomnia, anxiety, high blood pressure and cardiac complications should be aware that coffee consumption was likely to worsen their condition," said Grond.