Long-Term Coffee and Tea Intake Linked to Lower Dementia Risk, Large Harvard Study Finds
A Harvard-led study of 131,821 participants followed for up to 43 years found that drinking two to three cups of caffeinated coffee daily or one to two cups of tea daily was associated with an ~18% lower risk of dementia, lower prevalence of subjective cognitive decline, and better performance on cognitive tests, with decaffeinated coffee showing no benefits. Results held across genetic risk groups, suggesting caffeine may be the active protective factor, though the effect size is small and caffeine should be one part of a broader cognitive-health strategy.