Harvard study: A couple of daily cups of coffee or tea linked to lower dementia risk
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- Reviewed by Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
If you're a regular drinker of coffee or tea, you might rely on that morning cup to think more clearly through the day. A new study suggests your daily habit might help your brain in the long term, too.
In the study, published online Feb. 9, 2026, by JAMA, Harvard researchers evaluated dietary records of more than 131,000 people (66% women). They were followed for an average of nearly 37 years, during which 11,033 of them were diagnosed with dementia.
The analysis showed that people who drank the most caffeinated coffee (about two-and-a-half cups daily) had an 18% lower risk of dementia compared with those who drank little or no coffee. Coffee devotees also showed less decline on tests of thinking skills. People who drank the most caffeinated tea (one to two daily cups) had similar results. Interestingly, decaffeinated coffee didn't seem to have a protective effect.
The study was observational and can't prove conclusively that the caffeinated beverages protected participants' brains. However, other research suggests that the inflammation-fighting effects of caffeine and polyphenol compounds, found in both coffee and tea, may play a role.
Image: © Nikolay Ponomarenko/Getty Images
About the Author
Joyce Hendley, Staff Writer
About the Reviewer
Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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