If you’re the sort of person who regularly scans the latest science-related headlines, you’ve probably come across the coffee shuffle at some point: Articles reporting on the latest study to show coffee may do something good for you, followed by articles reporting on studies showing that coffee is actually the devil’s brew. So what should you take away from this mish-mash of research and should any of it affect your own coffee habits?
The main problem here is that science is rarely as definitive as headlines can make it out to be. The world is a complicated place, and the interactions between our body and the foods or drinks we put into it are often hard to tease out. Nutrition research is especially tricky to conduct since it usually takes years for a specific item in our diet to have any real effect on our long-term health. Most of the time, it’s not so much one kind of food that matters, but the shape of our diet. Eating too many highly processed foods regularly for too long might increase our risk of heart disease in our older years, for instance, but a single twinkie won’t.
Coffee is chock full of ingredients, though, including some known to acutely affect the body like the stimulant caffeine. And because coffee’s been one of the most popular foods in the world for centuries, it’s no surprise that hundreds, if not thousands, of studies have been devoted to finding out what it can do to us, usually through observational studies of a population or certain group of people.
In the past few years alone, studies claim to have found that coffee consumption is associated with a lower risk of heart failure; that it can stave off early death among the general public and in people with type 2 diabetes; and that it may even help undo the liver damage that can be caused by chronic alcohol use. Conversely, studies have suggested that excessive coffee drinking (over six cups a day) is linked to poorer health; that drinking it before, but not after, breakfast can muck with your metabolism; and that it may increase the risk of glaucoma in people genetically predisposed to the eye condition. The state of California also recently almost mandated that coffee products would need a label warning of potential cancer risk.
This sort of whiplash might be enough to cause any reasonable person to simply not bother paying attention to any new coffee-related headlines. But while science isn’t perfect, it’s a process that builds on repetition. When you’re trying to figure out the harms or benefits of any drug or substance, it’s best to look at the big picture, not just a single study, especially since most food studies can only show a correlation between two things, not a direct cause-and-effect relationship.
These reviews of the evidence aren’t foolproof either, but they give a good sense of the scientific consensus. And in truth, there’s a lot more evidence that coffee is generally good for us (or at least not harmful) than the opposite. Really, these days, it’s actually harder to come across negative coffee studies, as scientists have started to agree on its overall positives. California’s coffee cancer warning, by the way, was very dumb, but for reasons that weren’t really related to coffee in the first place.
Sure, like almost anything, coffee is best taken in moderation and too much of it may very well be bad for us. Children and people with certain conditions that could be worsened by stimulants like an anxiety disorder should probably also avoid or be more cautious about their habit (or switch to decaf, since the benefits of coffee seem to still be there). And if you do feel like your coffee consumption is more trouble than it’s worth, it’s of course fine to cut down or to talk to your doctor about it if possible. But yes, for the average joe, there’s nothing wrong with grabbing a cup of joe once in a while—it just might be a small health boost, if anything.