Drinking your morning cup of coffee or tea might do more than help you wake up—it could help protect your brain, too.
A new study published in JAMA has found that people who regularly consume caffeinated coffee or tea appear to have a lower risk of developing dementia than those who avoid caffeine entirely. The effect was most noticeable among individuals who drank two to three cups of coffee or one to two cups of tea per day.
The study tracked nearly 132,000 people over several decades, using data from two major U.S. health studies: the Nurses’ Health Study and the Health Professionals Follow-up Study. Participants, who began the studies in their mid-40s to mid-50s, completed detailed surveys every few years about their diet, including beverage intake. Over time, about 11,000 of them were diagnosed with dementia.
After adjusting for other health and lifestyle factors, researchers found that those with the highest intake of caffeinated coffee had an 18% lower risk of developing dementia compared to those who drank the least. Tea drinkers also saw benefits—those with the highest tea consumption had a 14% lower risk.
However, decaffeinated coffee didn’t show a similar link, which suggests that caffeine may play a key role. Still, researchers caution that caffeine is unlikely to be the only explanation.
“It is really a big challenge to disentangle the effects of coffee as a whole from all of the other compounds that are also in coffee—and tea,” said Dr. Kellyann Niotis, a preventive neurologist at Weill Cornell Medicine, speaking to NBC News. “It’s definitely possible that these other compounds are interacting with each other, or synergistically with the caffeine itself, to exert some benefit.”
Coffee contains hundreds of bioactive compounds that may influence brain health by reducing inflammation, improving blood flow, and regulating metabolism, said Sara Mahdavi, a nutrition researcher at the University of Toronto, in an email to CNN.
The researchers stress that while the results are promising, they’re not meant as a recommendation for people to start drinking coffee if they don’t already. “We are not recommending that people who don’t drink coffee start drinking,” said lead author Yu Zhang, a population health scientist at Mass General Brigham, in an interview with NBC News. “We are just seeing that for people who already drink coffee, the results are really reassuring.”
One key takeaway: more is not necessarily better. The benefit plateaued after about three cups of coffee or two cups of tea a day. Higher consumption didn’t lead to further risk reduction.
The findings were described as “very large” and “rigorous” by experts not involved in the study, including Dr. Aladdin Shadyab, a public health researcher at UC San Diego. He told The New York Times that the results align with previous research showing coffee may lower the risk of several age-related chronic diseases.
But experts also warn against thinking of coffee or tea as magic bullets. “Regular physical and frequent activity, good sleep hygiene, not smoking, managing blood pressure and diabetes, staying socially engaged and maintaining overall diet quality, which should be mainly made up of whole plant-based foods … remain far more influential than any single beverage,” Mahdavi said.
Still, if you already reach for a warm cup of coffee or tea in the morning, there may be one more reason to enjoy it. Just don’t expect it to work miracles on its own.
