If you’re reading this story during the morning — or maybe even the afternoon — there’s a good chance you have a cup of coffee in your hand.
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Coffee is not only a pervasive beverage of choice but also a popular subject for health research. In fact, doctors have been interested in the health effects of coffee since at least 17th century Europe, says cardiac surgeon Marc Gillinov, MD, co-author of Heart 411: The Only Guide to Heart Health You’ll Ever Need.
But what should consumers do with the results of these studies — especially when some tout the health benefits of coffee while others warn against the drink’s ill effects? The latter is the case with a recent study from Mayo Clinic that links excessive coffee drinking with premature death.
“Observational studies cannot prove causality. They suggest something, but they don’t prove cause and effect.”
What the study says
In this long-term observational study of 44,000 subjects, researchers found that drinking 4 cups of coffee per day may increase the risk of premature death by 21 percent. Among deaths of people in the study, 32 percent of them were related to heart disease.
Does this mean you should put down that cup of coffee? Not so fast, says Dr. Gillinov.
“This is an interesting study, but keep in mind that it is an observational study,” Dr. Gillinov says. “Observational studies cannot prove causality. They suggest something, but they don’t prove cause and effect.”
The message is moderation
When it comes to coffee, assessing health risks and benefits can be as muddy as a strong cup of joe. For example, people who drink it regularly are much less likely than non-drinkers to experience a mild rise in blood pressure or heart rate, Dr. Gillinov notes.
In addition, this particular study focused on excessive coffee drinking — in this case defined as 28 cups or more a week. With that in mind, if people do take away a message from the study, it should be a message of moderation.
“The message turns out to be the same old message about everything: alcohol, chocolate, saturated fats,” Dr. Gillinov says. “None of these in moderation is going to kill you outright. But it is possible that too much can be harmful.”