Drinking a couple of teas or coffees a day may lower the risk of dementia and slow cognitive decline, scientists say. A large US study found that people 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. Researchers analysed health data from more than 130,000 participants followed for up to 43 years, with results published in the Journal of the American Medical Association.
Caffeinated coffee drinkers also showed slightly better performance on cognitive tests than those who drank decaf. No protective link appeared for decaffeinated coffee. Lead author Yu Zhang of Harvard University said the study could not prove causation, but the findings matched biological theories. Caffeine and polyphenols in tea and coffee may protect brain health by improving blood flow, reducing inflammation, and supporting metabolic health.
Experts caution that caffeine has mixed effects and may raise blood pressure in some people. Researchers stress that tea and coffee are not substitutes for healthy habits. They say regular exercise, good sleep, and a balanced diet remain key to protecting the brain.
