2026-02-10 14:15:54
Drinking a couple of cups of coffee a day could help ward off dementia.
As part of a major new study led by Harvard researchers, scientists analysing decades of health data found that people with the highest caffeine intake were significantly less likely to develop dementia or experience age-related cognitive decline later in life.
The findings add to growing evidence that brain health can be protected long before symptoms ever appear.
Dementia affects around one in 10 adults over 65 and is driven by a mix of genetics, lifestyle and environmental factors.
Previous studies have shown that cutting alcohol, avoiding ultra-processed foods and prioritising sleep can lower risk. Now, attention has turned to caffeine.
Researchers at Mass General Brigham – a Harvard-affiliated hospital – examined health records from more than 130,000 Americans tracked over more than 40 years. They looked at how much caffeine participants consumed from coffee, tea, soda and chocolate.
Those who consumed the most caffeine – equivalent to two to three cups of coffee or one to two cups of tea per day – had an 18 per cent lower risk of developing dementia compared to people who drank little or none.
Caffeinated coffee drinkers were also 20 per cent less likely to show cognitive decline and performed better on memory and thinking tests.
Dr Daniel Wang, senior study author, and associate scientist at the Mass General Brigham Department of Medicine, said: “When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention.
“While our results are encouraging, it’s important to remember that the effect size is small. Caffeinated coffee or tea consumption can be one piece of that puzzle.”
The researchers believe caffeine, along with polyphenols found in coffee and tea, may reduce inflammation in the brain and limit cellular damage linked to dementia.
Notably, decaffeinated drinks offered no protection, suggesting caffeine itself is key.
The study, published in JAMA, drew on data from long-running studies of nurses and health professionals.
Of the participants, more than 11,033 developed dementia during the follow-up period. However, outside experts urged caution.
Naveed Sattar, professor of cardiometabolic medicine and an honorary consultant at the University of Glasgow, warned:”A major concern is residual confounding: unmeasured factors that cannot be fully accounted for.
“In this case, people who drink moderate amounts of tea or coffee may simply lead more balanced, healthier lives overall, and it may be these broader lifestyle patterns – not the drinks themselves – that relate to better brain health.
“There is currently no strong evidence from randomized trials that tea or coffee meaningfully improve recognized risk factors for brain health, such as blood pressure, cholesterol, or glucose levels. For these reasons, I would interpret these findings with considerable caution.
“The fundamentals of protecting brain health remain unchanged: maintaining good cardiovascular risk factors, eating a healthy diet, staying physically active, keeping alcohol intake low, and engaging in regular mental stimulation.”
Professor Tara Spires-Jones, Division Lead in the UK Dementia Research Institute, and was not involved in the study, agreed adding that lifestyle fundamentals still matter most.
She said: “This is a well-conducted study that looked at data from a large number of people over many years. However, the study does have important limitations.
“This kind of observational research cannot prove conclusively that caffeine intake was the reason for lower dementia risk, other factors related to coffee and tea drinking habits could be responsible.”
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