A large new study published in JAMA has linked moderate coffee and tea consumption to a lower risk of dementia. Researchers at Mass General Brigham and Harvard tracked participants for as long as 43 years, making it one of the most extensive investigations yet into caffeine and long-term brain health.
The Study's Findings
The research drew on data from 131,821 participants in the Nurses' Health Study and the Health Professionals Follow-Up Study. Over the study period, 11,033 participants developed dementia. People who drank the most caffeinated coffee, about two to three cups a day, showed an 18 percent lower risk of dementia compared with those who drank little or none. People who drank one to two cups of caffeinated tea daily showed similar benefits. Decaffeinated coffee did not show the same protective association.
Understanding Caffeine's Role
The study is observational, so it cannot prove that caffeine directly causes these effects. Even so, the researchers adjusted for variables such as health conditions, education, and lifestyle habits, which strengthens confidence in the association. Researchers point to compounds beyond caffeine, particularly polyphenols in coffee and tea, as possible contributors. Scientists believe these compounds support heart health, reduce inflammation, and improve gut health, and they may also help protect cognitive function.
Industry Implications
These findings could shape how the health and wellness sector talks about caffeine, potentially encouraging moderate coffee or tea intake as one piece of a broader strategy for reducing chronic disease risk. Because researchers linked decaf to no measurable benefit, companies may also start marketing caffeinated products specifically around cognitive health rather than treating caffeine as interchangeable with decaf.
What This Means for You
Coffee and tea may support cognitive health, but people should weigh that benefit against their broader health picture rather than treat caffeine as a standalone fix. Researchers need more work to determine how caffeine interacts with other lifestyle factors and to refine recommendations for different populations, including people with heart conditions or anxiety disorders who may need to limit caffeine regardless of its cognitive upside.
