People who drink a few cups of tea or coffee each day face a lower dementia risk, scientists report.
A large US study tracked more than 130,000 people over four decades.
Those drinking two to three coffees or one to two teas daily had a 15–20% lower dementia risk.
Caffeinated coffee drinkers also showed slightly slower cognitive decline.
Researchers published the findings in Journal of the American Medical Association.
The study found no protective link with decaffeinated coffee.
Lead author Yu Zhang from Harvard University said the results do not prove cause and effect.
Coffee and tea may protect the brain through caffeine and antioxidants.
Experts caution that caffeine can also raise blood pressure in some people.
Scientists stress that healthy lifestyle choices remain the strongest protection against dementia.
