Overview
- Habitual intake of about 300 mg of caffeine daily—roughly 2–3 cups of coffee—was associated with an approximately 18% lower risk of dementia.
- Caffeinated tea showed a smaller association, with about 1–2 cups a day linked to roughly a 14–16% lower risk.
- Decaffeinated coffee showed no protective association in the analyses.
- The apparent benefit plateaued around 300 mg of caffeine per day, with no additional protection at higher intakes.
- Findings came from the Nurses’ Health Study and Health Professionals Follow-up Study (131,821 participants, up to 43 years, 11,033 dementia cases) and were consistent across genetic risk groups; researchers stress the study is observational and cannot prove causation.