The researchers looked at the coffee habits of 17,702 UK Biobank participants who had MRIs on file. The UK Biobank is a massive biomedical database comprising genetic and health information from half a million people in the UK. From the data, researchers discovered that six or more cups of coffee per day correlated with a 53 percent increased risk of dementia.
Given that their participants ranged widely in age, from 37-73, the researchers also measured brain volume as an indicator of diminished brain health. Again, those who habitually drank six or more cups of coffee per day had smaller brains in MRI images taken four to six years after their first. “Brain volume is a rough indicator of physical and structural injury in the brain,” says Joel Salinas, MD, MBA, assistant professor of neurology at NYU Grossman School of Medicine. The brain naturally atrophies as people get older, but you’d expect a greater degree of atrophy in people who have early signs of neurodegenerative diseases like dementia and Alzheimer’s. The study doesn’t explicitly show that coffee consumption causes brain shrinkage, but the findings could be worth noting.
So what does this mean for your coffee habits? Coffee has a bad reputation, but it’s rich in antioxidants, vitamins, and minerals. There’s even research that suggests compounds in coffee might positively impact proteins in the brain connected to Alzheimer’s and Parkinson’s, Ajeet Sodhi,MD, a neurologist and the director of neurocritical care at the California Institute of Neuroscience, previously told Well+Good. In short: It’s fine to consume your pick-me-up (in a cup) in moderation.
If you usually drink one or two cups a day, with the occasional coffee binge on days when you really need the caffeine, there’s no need to worry. This and other research put your coffee drinking squarely in the safe zone. Erika Schwartz, MD, previously told Well+Good that 400 milligrams of caffeine per day (about four or five eight-ounce cups of coffee) is safe for most adults. Her advice lines up well with this new research, claiming the cutoff is six cups a day.
And, while a steady stream of coffee and caffeine might have health risks (caffeine can stimulate your nervous system and make anxiety worse), coffee isn’t the most important brain health habit to worry about, Dr. Salinas says. Our brains depend on healthy habits like staying hydrated, getting enough sleep, exercising, and eating a well-balanced diet. Excessive coffee drinking, he says, is often an unproductive substitute for some of these other behaviors. “People often rely too much on caffeine and ignore all of these other lifestyle factors that are meant to keep us performing at our best,” he says. Caffeine is a quick fix when we’re too tired to function, but it can quickly become a crutch.
Still, if your occasional coffee binge becomes more frequent, it’s okay to rethink your daily intake. “Don’t necessarily stop coffee cold turkey,” Dr. Salinas says. “I mean, that would give you a headache anyway.” But you might want to take a look at why your coffee habits became so excessive and adjust so you can cut back on the caffeine and get more sleep or build up your energy with water and exercise instead.
Good brain health habits may be especially important if you have a genetic risk of neurodegenerative diseases like Alzheimer’s, Dr. Salinas. If you have a grandmother who has dementia, for instance, you aren’t genetically doomed to the same fate. You can lower your risk with healthy habits and cognitively challenging activities like aquiring a new language, learning how to dance, or expanding your reading, Dr. Salinas says. However, it’s important to remember that our brain health also depends on social determinants like structural racism and socioeconomic disparities, Dr. Salinas says. “It’s like gaslighting to say that it’s 100 percent in your control,” he says. We have some control over our brain health, of course, but we also live in a larger world that affects our behavior.
When it comes to coffee, this new research, as well as research before it, points to a potential threshold where coffee goes from a delightful, and actually healthy, drink to a possible liability. Like with anything else we put into our bodies, moderation is key.
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