People who drink a few cups of tea or coffee each day may face a lower risk of dementia, researchers say. A long-term US study found that adults who drank two to three cups of caffeinated coffee or one to two cups of caffeinated tea daily had a 15–20% lower dementia risk than non-drinkers. The research analysed health records from more than 130,000 participants followed for up to 43 years and was published in Journal of the American Medical Association.
Caffeinated coffee drinkers also showed slightly less cognitive decline and better performance on some brain tests than those who drank decaf. No protective link appeared for decaffeinated coffee. Lead author Yu Zhang of Harvard University said the study cannot prove cause and effect, but the findings align with biological theories. Tea and coffee contain caffeine and polyphenols that may reduce inflammation, improve blood vessel health, and support metabolism, all linked to brain ageing.
Experts urge caution. Naveed Sattar from the University of Glasgow noted caffeine can also raise blood pressure in some people, which increases dementia risk. Researchers stress that tea and coffee are no substitute for proven measures such as exercise, healthy diet, good sleep, and managing blood pressure.
