- A new study that analyzed data from 131,821 people found that those who drank higher levels of caffeine had an 18% lower risk of dementia compared to those who had little or no levels of caffeine.
- It could be that caffeine improves signaling between neurons in the brain as well as blood flow, but more research is needed to prove this link and dig into the why of it all.
- Still, moderation is important as too much caffeine can mess with sleep and increase stress levels, which can negatively influence cognitive aging.
The next time you stumble out of bed and make a beeline for your coffee maker, know this: You could be doing your brain health a solid.
That’s the major takeaway from a new study by researchers at Harvard that found a link between having a few cups of coffee or tea a day and better cognitive health over time. The findings don’t necessarily suggest that you should take up a coffee habit if you don’t already drink it, or that drinking coffee should be the only thing you do for the good of your brain—but they can make you feel better about continuing to sip coffee if it’s your drink of choice.
Here’s the deal, plus what neurologists and a dietitian want you to keep in mind.
Meet the experts: Agenor Limon, PhD, is an associate professor of neurology and director of the Mitchell Center for Neurodegenerative Diseases at the University of Texas Medical Branch. Clifford Segil, DO, is a neurologist at Providence Saint John’s Health Center in Santa Monica, CA. Jessica Cording, RD, CDN, is the author of The Little Book of Game-Changers.
What did the study find?
The study, which was published in JAMA, analyzed data from 131,821 people who participated in two long-term biomedical databases: the Nurses’ Health Study and Health Professionals Follow-Up Study.
Participants provided information on their diet, while researchers analyzed health data for up to 43 years afterward. During the study period, 11,033 people developed dementia. But the researchers discovered that people who drank higher levels of caffeine had an 18% lower risk of dementia compared to those who had little or no levels of caffeine. Still, this is an association, not definitive proof of cause and effect.
The biggest differences were observed in people who had two to three cups of caffeinated coffee or one to two cups of tea per day.
People who drank caffeinated coffee also had lower levels of cognitive decline (7.8% compared to 9.5%) and they performed better on cognitive function tests.
People who drank caffeinated tea had similar results, although decaf coffee didn’t offer the same perks. That suggests that caffeine may be the big factor here, per the researchers.
Why might caffeine boost the brain?
It’s not entirely clear, but there are a few theories.
“Caffeine is a psychostimulant that has direct effects on the chemistry of the brain and the vascular system,” says Agenor Limon, PhD, associate professor of neurology and director of the Mitchell Center for Neurodegenerative Diseases at the University of Texas Medical Branch. It temporarily improves signaling between neurons in the brain, along with blood flow to enhance memory, attention, and cognitive performance, he explains. There may be something in this process that can help to lower the risk of dementia, he says.
Coffee and tea also contain bioactive ingredients like polyphenols and caffeine, which may help to reduce inflammation and cellular damage while protecting against cognitive decline, the researchers said in the study.
What's more, coffee can be part of a ritual of socializing with friends, and that's good for brain health, Limon says.
But there's still work to be done around using caffeine to lower the risk of dementia, says Clifford Segil, DO, a neurologist at Providence Saint John’s Health Center in Santa Monica, CA. “The idea that moderate caffeine intake can modestly improve cognitive function remains unproven,” he says.
The Caffeine Sweet Spot for Brain Health
Experts stress that moderation is important. “One to three cups a day may support alertness and possibly long-term brain health,” Limon says. But too much caffeine can mess with sleep and increase your stress levels, which can influence cognitive aging, he says. “The goal is to find the personal sweet spot by paying attention to your body,” Limon says.
It’s generally recommended that you have no more than 400 milligrams of caffeine a day, says Jessica Cording, RD, CDN, author of The Little Book of Game-Changers. “It also matters how you’re taking your caffeinated beverages,” she says. Putting a lot of sugar into your coffee could increase inflammation in your body, which would likely work against your healthy brain goals, she says.
Ultimately, Dr. Segil recommends that you simply enjoy your cup or two of coffee, knowing that it may support your brain health over time—just don’t go overboard with it.
