Drinking a daily cup of coffee -- or even several cups -- isn't likely to harm your health, and it may even lower your risk of dying from chronic diseases such as diabetes and heart disease. And it doesn't matter whether it's regular or decaf.

The study of 400,000 people, published in the New England Journal of Medicine, is the largest ever done on the issue, and the results should reassure any coffee lovers who think it's a guilty pleasure that may do harm.

Some studies have linked coffee drinking to better health and a lower risk of premature death, while others suggest that coffee -- or rather caffeine -- might contribute to heart disease through negative effects on blood pressure, cholesterol, and heart rate.

Overall, coffee drinkers were less likely than their peers to die during the study, and the more coffee they drank, the lower their mortality risk tended to be. Compared with people who drank no coffee at all, men and women who drank six or more cups per day were 10% and 15% less likely, respectively, to die during the study. The study was done by the National Institutes of Health and AARP.

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