Drinking copious amounts of coffee not only isn't harmful to your health, it may actually protect you from heart disease, especially if you're a woman, new research suggests.

Researchers from Harvard School of Public Health, Brigham and Women's Hospital, Harvard Medical School and the Universidad Autonoma de Madrid studied the effects of coffee consumption on 41,736 men and 86,214 women over 18-year and 24-year periods respectively.

Participants with a history of heart disease or cancer at the onset of the study were excluded.

They discovered that women who drank two to three cups of caffeinated coffee per day had a 25 per cent lower risk of death from heart disease during the study's followup period (1980 to 2004) than non-coffee drinkers. They also had an 18 per cent lower risk of dying from an illness other than cancer or heart disease during followup.

Women who drank five to seven cups of coffee a week had a seven per cent lower risk of death from all causes than non-drinkers.

In men, researchers saw non-statistically significant benefits and no downsides to drinking two to three cups of coffee, or five to seven cups of coffee daily.

The caffeine content was estimated by researchers at 137 mg per cup of coffee.

Participants filled out questionnaires about their coffee-drinking habits and health conditions every two to four years. Drinking more coffee per day did not increase a person's chance of dying during the followup period, according to the authors.

"We did not find a detrimental effect of coffee consumption on mortality," they write.

No cancer correlation

The researchers did not find any correlation between drinking coffee and cancer deaths.

During the study, 2,368 women died due to heart disease, 5,011 passed away from cancer, and 3,716 died from other causes. Among men, 2,049 died due to heart disease, 2,491 succumbed to cancer, and 2,348 died due to other causes.

Though the study points to a somewhat protective effect of drinking coffee, particularly among women, the researchers emphasize that the study design does not allow them to make definitive conclusions about coffee's value in protecting against heart disease.

They believe other factors may play a part in protecting coffee drinkers and that further study is needed.

The study is to be published Tuesday in the Annals of Internal Medicine.