Yes, people have been concerned about it since the 16th century, but as long as we’ve been analyzing its effects we’ve observed that drinking coffee tends to improve your health, not harm it. In moderation, of course.
The high-volume coffee drinkers were more healthy. And that’s exactly what they found. Across 502,641 participants ranging from 38 to 73 years old, both male and female, the more coffee a person drank the less likely they were to die. The researchers published their results in JAMA Internal Medicine on Monday.
All of these findings generally line up with what other large-scale studies have found: drinking more coffee tends to correlate with good health and fewer deaths. Here is a 2017 European study showing that, with 521,330 people. Here’s one from 2012 involving 5,148,760 Americans finding the same inverse correlation. And here’s another from 2017 focusing on nonwhite populations in the U.S., still finding that drinking coffee is generally associated with lower risk of death.
They did find, somewhat unsurprisingly, that those with a higher “caffeine metabolism score”—those who metabolize caffeine faster—tended to drink more coffee.
If you’re one of those people who can’t have more than a cup without getting jittery, but still want to drink joe, don’t worry—you can drink decaf and still get the health benefits.
This study, like others, found that the caffeine content made no difference to the risk of death. Researchers aren’t sure what’s in coffee that seems to boost our health, but the scientists on this study noted it provides further evidence that the secret ingredient isn’t caffeine. One 2005 study in JAMA suggested that it could be compounds that reduce inflammation and insulin resistance, like lignans, quinides, and magnesium.
Caffeine is a stimulant, and though “too much” depends on your personal metabolism, an overload can give you headaches, irritability, restlessness, a fast heartbeat, and muscle tremors. Plus it can deprive you of sleep. The Mayo Clinic recommends limiting yourself to about 400 milligrams a day for that reason. It also doesn’t mean that you can put oodles of sugar and cream in without having other negative health effects, like obesity or heart disease. But it does mean that the average person can drink their moderately-sugared, lightly-creamed joe in peace—even though we already knew that.