People who drink a couple of teas or coffees a day appear to have a lower risk of dementia and slightly better cognitive performance, scientists say. A US study tracking more than 130,000 people over 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 were published in Journal of the American Medical Association.
Researchers also found less cognitive decline among caffeinated coffee drinkers compared with those who chose decaf, which showed no protective effect. The analysis drew on long-term data from two major US health studies and suggests the benefit plateaus at moderate intake. Lead author Yu Zhang of Harvard University said the results cannot prove causation but align with biological theories linking caffeine and polyphenols to reduced inflammation, better vascular health, and improved metabolism.
Experts caution against overinterpreting the findings. University of Glasgow professor Naveed Sattar noted caffeine can also raise blood pressure in some people, which increases dementia risk. Researchers stress tea and coffee are not a cure and that exercise, diet, sleep, and managing health risks remain central to protecting brain health.
