2-3 cups of caffeinated coffee daily may lower dementia risk: Study

Drinking moderate amounts of caffeinated coffee or tea may be linked to a lower risk of dementia and modestly better cognitive function, according to a large long-term study published in Journal of the American Medical Association (JAMA).

The study, titled “Coffee and Tea Intake, Dementia Risk, and Cognitive Function”, found that the strongest benefits were observed among people who consumed two to three cups of caffeinated coffee per day or one to two cups of tea daily. Researchers noted that the benefits appeared to plateau beyond these levels, suggesting there may be a limit to how much caffeine the body can effectively metabolise.

The analysis included 131,821 participants from two large US cohorts, the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Participants were followed for up to 43 years, during which 11,033 cases of dementia were identified through medical diagnoses and death records.

After adjusting for multiple lifestyle and health factors, researchers found that higher intake of caffeinated coffee was associated with a significantly lower risk of dementia. Those in the highest consumption group had 141 cases per 100,000 person-years, compared to 330 cases among those with the lowest intake. The hazard ratio for dementia was 0.82, indicating an 18% lower risk.

Higher caffeinated coffee intake was also linked to a lower prevalence of subjective cognitive decline, based on questionnaire assessments. In the NHS cohort, participants with higher intake additionally showed slightly better performance on objective cognitive tests, including the Telephone Interview for Cognitive Status (TICS).

Tea consumption showed similar protective associations, while decaffeinated coffee did not demonstrate any link to reduced dementia risk or improved cognitive performance.

Researchers highlighted a non-linear dose-response relationship, meaning the benefits were most pronounced at moderate consumption levels, rather than increasing steadily with higher intake.

The study’s authors concluded that regular, moderate consumption of caffeinated coffee and tea may play a role in supporting long-term brain health, though they emphasised that the findings show an association rather than direct causation.