People who drink a couple of teas or coffees a day appear to have a lower risk of dementia and slightly better cognitive performance, researchers say. A US study tracking more than 130,000 people for up to 40 years found that those 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 findings, published in the Journal of the American Medical Association, also showed slightly less cognitive decline among caffeinated coffee drinkers compared with those who chose decaf.
Researchers caution the results do not prove caffeine protects the brain, as other factors may explain the link. Lead author Yu Zhang of Harvard University said the evidence fits plausible biology, including effects on blood vessels, inflammation, and metabolism. Experts note caffeine can also raise blood pressure in some people, which increases dementia risk. Scientists stress that coffee and tea are no substitute for a healthy lifestyle, exercise, good sleep, and balanced diet.
