Tea and coffee consumption linked with lower dementia risk at moderate levels

A long-term study of about 131,000 US health professionals found that moderate daily intake — roughly two to three cups of caffeinated coffee or one to two cups of tea — was associated with a lower risk of dementia, while decaffeinated coffee showed no clear link.

Researchers analysed dietary and cognitive data from more than 130,000 US health professionals tracked over decades to explore links between caffeinated beverages and dementia. Participants completed questionnaires about caffeinated and decaffeinated coffee and tea every two to four years, and cognitive tests were performed at intervals. During the follow-up period, over 11,000 cases of dementia were identified and associations with beverage intake were examined. The study authors reported the strongest associations at moderate intake levels rather than at high consumption. Key findings: - The analysis used data on about 131,000 health workers followed on average for several decades, with repeated dietary assessments. - Higher intake of caffeinated coffee was associated with a lower dementia risk; the highest consumers had about an 18% lower risk compared with the lowest consumers in the study. - People who drank the most tea showed a similar association, with around a 16% lower risk observed for higher tea intake. - The most pronounced associations were at moderate levels: roughly two to three cups of caffeinated coffee per day, or one to two cups of tea per day. - Decaffeinated coffee was not associated with lower dementia risk or better cognitive performance in the reported analyses. - The study is observational, used self-reported dietary data collected every two to four years, and was conducted in relatively similar groups of health professionals, which the authors and external experts noted as limitations. Summary: The study reports modest associations between moderate caffeinated coffee or tea intake and lower dementia risk, with no additional apparent benefit at higher consumption levels. Further research is needed to clarify whether these associations reflect a direct protective effect of caffeinated beverages or other related factors; Undetermined at this time.