Your morning cup of java could be doing more than just providing a jolt to your day. A study out today suggests that caffeinated coffee and tea can also promote a healthier brain.
Researchers in Boston, Massachusetts, examined the health records of nurses and other medical professionals. People who reported drinking the most coffee and tea were noticeably less likely to develop dementia later in life, they found. It might only take a few cups of either drink a day to obtain these benefits, they also found.
“Greater consumption of caffeinated coffee and tea was associated with lower risk of dementia and modestly better cognitive function, with the most pronounced association at moderate intake levels,” the researchers said in their paper, published Monday in the journal JAMA.
A prospective look at caffeine and dementia
Plenty of research has attempted to explore how coffee and tea consumption can affect our health.
Most of these studies rely on observational population-level data, however, which can only show a correlation between any two factors, not a direct cause-and-effect. These studies are often also limited by other caveats, such as only looking at people’s diets during a single point of their lives. This can make it harder to examine the impact of a specific food, since our diets can change.
In this new study, researchers at the Broad Institute of MIT and Harvard, Mass General Brigham, and Harvard Medical School examined data from two similar projects: the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS). Both the NHS and HPFS are prospective studies, meaning they proactively tracked people’s health over time (retrospective studies are easier to conduct but harder to pull high-quality data from). Volunteers in these studies were also asked to disclose their dietary habits every few years, allowing the researchers to study and compare people who were regular coffee/tea drinkers.
The studies collectively involved 131,821 participants, who were followed for up to 43 years. Of these, roughly 11,000 people developed dementia during the study period.
Compared to people who reported drinking little to no coffee or tea, those who drank the most had lower odds of developing dementia, the researchers found. Those in the 75th percentile and above of coffee/tea consumption were 18% less likely to later have dementia. These coffee/tea drinkers were also slightly less likely to report any subjective cognitive decline compared to non-drinkers (7.8% versus 9.5%), and coffee drinkers specifically seemed to perform better on some cognitive tests.
Importantly, this pattern wasn’t seen with decaffeinated coffee or tea, suggesting that caffeine is the crucial ingredient for better brain protection (some studies have suggested that decaf beverages can still have some benefits, though).
What to think about your coffee habit
Even prospective studies like the NHS and HPFS can only be used to demonstrate a correlation between coffee and reduced dementia. And the researchers note that if caffeinated coffee and tea can truly stave off dementia, their effect is likely to be modest at best.
That said, the majority of studies have suggested that coffee and tea consumption is a net positive to our health, including for our brains. A 2024 review, for instance, estimated that coffee was associated with a 10% lower relative risk of dementia.
You also don’t need to drink much caffeine to see these benefits. The researchers failed to find any significant reduction in dementia risk for the biggest coffee and tea drinkers compared to moderate drinkers. And the sweet spot for dementia prevention appeared to be around two to three daily cups of coffee or one to two cups of tea.
So as long as you’re not drinking obscene amounts of caffeine (like certain celebs), your health should be more than fine. And you’re probably doing your brain a small favor.
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