Moderate coffee and tea consumption linked to reduced dementia risk

A large observational study of 131,821 U.S. nurses and health professionals followed for up to 43 years found that moderate daily intake of caffeinated coffee or tea was associated with a substantially lower risk of dementia. Participants who consumed about 250‑300 mg of caffeine per day—roughly two to three cups of coffee or one to two cups of tea—had approximately a 35 % lower incidence of dementia compared with low or non‑consumers. The protective effect plateaued at this level; higher caffeine doses did not provide additional benefit, and decaffeinated coffee users showed faster memory decline, possibly reflecting underlying health issues.

The analysis, published in JAMA, noted that the association held across genetic risk groups and was strongest in adults aged 75 and younger. Researchers suggested biological mechanisms such as adenosine‑receptor blockade, reduced inflammation, and improved cerebral blood flow, though the study’s observational design precludes definitive causal conclusions.

These findings add to growing evidence that regular, moderate caffeine intake may support brain health, but they also emphasize the need for balanced consumption and further research to confirm causality.