People who drink a couple of teas or coffees a day appear to have a lower risk of dementia, scientists say. A large US study found that those who regularly consumed two to three cups of caffeinated coffee or one to two cups of caffeinated tea had a 15–20% lower dementia risk over decades than non-drinkers. They also showed slightly better cognitive performance and slower decline.
Researchers analysed health data from more than 130,000 participants followed for up to 43 years. The findings, published in Journal of the American Medical Association, showed no similar benefit from decaffeinated coffee. Lead author Yu Zhang of Harvard University said the study could not prove causation, as lifestyle factors may explain part of the link.
Scientists believe caffeine and plant compounds in tea and coffee may protect the brain by improving blood vessel health and reducing inflammation. However, experts caution that caffeine can also raise blood pressure in some people. Researchers stress that tea and coffee are not a cure, and that exercise, healthy diet, good sleep and avoiding smoking remain the most effective ways to protect brain health.
