We once thought coffee was unhealthy and did our best to cut down, but that was a long time ago. Nowadays, research is accumulating that our cup of comfort is actually very healthy. A new study adds further weight: drinking two to three cups of coffee per day reduces the risk of dementia.
And it’s not just some obscure study that came to this conclusion: scientists from Harvard and Mass General Brigham analyzed data from more than 130,000 people and were able to follow participants for up to 43 years.
Why prevention is so important
Table of Contents
With dementia, almost more than with any other disease, prevention is better than cure. In fact, there is no cure and what treatments are available have only a limited effect. It is therefore logical that researchers will look at lifestyle factors, such as food and drink, to prevent or delay the disease.
And coffee appears to help, probably because of the polyphenols and caffeine. These substances can reduce inflammation and cell damage, thus protecting against cognitive decline. Yet previous findings about coffee and dementia were inconsistent. Many studies had a short follow-up or did not sufficiently address the differences between, for example, coffee with and without caffeine, or they did not look at the full spectrum of memory problems: from subjective decline to real dementia.
Unique data spanning decades
With the new data something could be said about this. Participants repeatedly reported their diet, any dementia diagnoses, subjective cognitive decline, and performance on objective cognitive tests. The researchers specifically compared the effects of coffee with and without caffeine and tea.
Of the more than 130,000 participants, more than 11,000 developed dementia. The men and women who drank a lot of caffeinated coffee had an 18 percent lower risk than those who drank little or no caffeinated coffee. In addition, subjective cognitive decline was less common among coffee drinkers (7.8 percent versus 9.5 percent). On some measures, they also scored better on tests of overall cognitive function.
Caffeine seems to be the key
Higher tea consumption showed similar results. Decaffeinated coffee did not. This indicates that caffeine likely plays an important role, although further research is needed to confirm the precise mechanisms.
The greatest cognitive benefits were seen in participants who drank two to three cups of caffeinated coffee or one to two cups of tea daily. Striking: in contrast to previous studies, a higher caffeine intake did not lead to negative effects. Rather, it provided similar protective benefits as the optimal amount. Good news for diehard coffee drinkers: more is not necessarily worse.
Genetic predisposition also appeared to make no difference. “We compared people with different genetic predispositions to dementia and saw the same results. This means that coffee or caffeine is likely to be equally beneficial for people with high and low genetic risk,” said lead researcher Yu Zhang.
Small effects
Colleague Daniel Wang emphasizes that the findings must be interpreted with nuance: “Although our results are encouraging, it is important to remember that the effect is small and that there are many ways to protect cognitive functions as we age. Our study shows that drinking caffeinated coffee or tea may be part of that puzzle.”
Coffee and tea are therefore not miracle cures, but in addition to other lifestyle factors, they can make a modest contribution to protecting our brains as we age.
We have written about this subject before, for example also read Good news about coffee again: it prevents aging in people with psychological problems and Is your coffee not strong enough? This way you can make a stronger cup with as few beans as possible. Or read this article: Coffee turns out to be even better for your health than thought.
Finished? Also listen to the Scientias Podcast:
date:2026-02-09 16:00:00