Overview
- The JAMA analysis pooled 131,821 participants from the Nurses’ Health Study and Health Professionals Follow-up Study, tracking diets and cognition for up to 43 years and identifying 11,033 dementia cases.
- Greatest associations were seen at roughly two to three cups of caffeinated coffee or one to two cups of tea daily, correlating with slower cognitive decline over time.
- Participants with the highest caffeinated coffee intake had about an 18% lower dementia risk than those with the lowest intake; heavier tea drinkers saw roughly a 14%–16% lower risk.
- Decaffeinated coffee showed no association with reduced risk, pointing to caffeine or related bioactive compounds as likely drivers according to the authors.
- Findings were consistent across genetic risk strata, including APOE4 carriers, though experts stress the effect is small and emphasize proven measures such as exercise, healthy diet and sleep.