Downing at least a cup of coffee a day seems to decrease the risk of stroke, according to a new Swedish study.

The 10-year study found that women who drank one or more cups of coffee a day were up to 25 percent less likely than women who drink less than one cup a day to have a stroke, said study researcher Susanna Larsson, of the Division of Nutritional Epidemiology at the Karolinska Institute in Sweden.

"Although the most appropriate amount of coffee per day is still uncertain, it seems that drinking about one to five cups a day is appropriate" to reduce stroke risk, Larsson told MyHealthNewsDaily.

Her previous research suggested a similar benefit for men, Larsson said.

The study was published today (March 10) in Stroke: Journal of the American Heart Association.

Coffee consumers

Larsson and her colleagues recorded the coffee-drinking habits and health histories of 34,670 women ages 49 to 83 for about 10 years. By the end of the period, 1,680 women had suffered a stroke.

Adjusting for stroke risk factors such as smoking, body mass index, diabetes history, blood pressure and alcohol consumption, the researchers found that the daily coffee drinkers were 22 to 25 percent less likely to have a stroke.

The apparent protective effect of coffee was about the same whether the women drank one to two cups or drank five, the study said.

In a study of 26,556 male smokers in Finland, published in 2008 in the journal Stroke, Larsson found that those who drank eight or more cups of coffee a day were 23 percent less likely to have a stroke over a 13-year period than men who didn't drink coffee. And men who had two or more cups of tea a day had a 21 percent decreased risk of stroke , that study said.

How it works

Coffee's protective effect may come from its high concentration of antioxidants, Larsson said. Coffee consumption also has been shown to reduce inflammation and oxidative stress, improve insulin sensitivity and reduce the risk of diabetes , she said.

"Given that the effects of coffee on inflammation, oxidative stress, insulin sensitivity and endothelial function happen quite fast, it is probably never too late to start drinking coffee," she said. Endothelia are layers of cells that line the inside of blood vessels, including in the kidneys and heart.

Other studies also have shown coffee has a protective effect against stroke. A study of 83,000 women, published last week in the journal Circulation, showed that those who drank two or three cups of caffeinated coffee a day had a 19 percent lower risk of stroke than those who drank less than one cup a month. And the study associated drinking four or more cups of coffee a day with a 20 percent decreased stroke risk.

Pass it on: Drinking one or more cups of coffee a day can decrease your stroke risk.

Follow MyHealthNewsDaily staff writer Amanda Chan on Twitter @AmandaLChan.