What happened
Coffee consumption will not kill you, according to a study from Harvard and the Universidad Autonoma de Madrid. The study followed the drinking habits of nearly 128,000 men and women over 18 to 24 years, and found that women who drink two or three cups a day—with or without caffeine—have a 25 percent lower risk of dying from heart disease than non-drinkers. For men, coffee drinking did not raise or lower heart-disease-related deaths.

What the commentators said
We are "delighted to learn that our morning wakeup fared well in this study," said the Wall Street Journal's Health Blog. But "we must also dutifully report that there is reason to be skeptical about the results." The researchers did not observe the study's participants directly—instead, the participants reported on their own drinking habits, diet, and exercise. This is called self-reporting, "which tends to be unreliable."

That's one reason why this study doesn't prove that coffee will lengthen your life, said Kathleen Doheny in The Washington Post. The take-away point is that "drinking up to six cups a day of caffeinated or decaffeinated coffee daily won't shorten your life span," and it might—might—even have some health benefits.

"Some experts still warn, however, that caffeine can lead to detrimental short-term health effects, such as anxiety and sleep problems," said Angela Haupt in USA Today. But since the results of the Harvard-Madrid study applied to people who drank decaf, too, it's possible to avoid negative effects from caffeine while still reaping any possible health benefits.