For many people, coffee is part of the daily routine. A new long-running study suggests it may also be linked to a small but measurable benefit for brain health later in life.
Researchers analyzing data from more than 130,000 adults found that people who regularly drank moderate amounts of caffeinated coffee or tea had a lower risk of developing dementia and showed slightly better cognitive performance over time than those who drank little or none.
The findings, published in JAMA, come from decades of follow-up data collected through two major U.S. health studies that have tracked diet and health outcomes since the 1980s. Participants repeatedly reported their coffee and tea intake and completed assessments related to memory, thinking skills and diagnosed dementia.
Compared with people who rarely drank caffeinated coffee, those who consumed about two to three cups per day had a lower likelihood of developing dementia over the course of the study. Similar patterns were seen among people who drank one to two cups of tea daily. Decaffeinated coffee, however, was not associated with the same cognitive benefits.
The differences were modest. Researchers emphasize that coffee is not a preventive treatment for dementia, and the study does not prove that coffee or tea directly protects the brain. Still, the consistency of the association over many years suggests that moderate caffeine intake could play a small role in supporting cognitive health as people age.
The study also found that people who drank caffeinated coffee reported slightly less subjective cognitive decline and performed somewhat better on certain objective tests of cognitive function. These patterns held regardless of participants’ genetic risk for dementia.
Scientists suspect caffeine may be part of the explanation, though coffee and tea also contain other compounds that may influence inflammation and brain signaling. The study was not designed to determine which components matter most.
Researchers caution that coffee should be viewed as just one piece of a much larger picture. Physical activity, overall diet quality, cardiovascular health, sleep and social engagement remain far more influential factors in long-term brain health.
This research was supported by grants from the National Institutes of Health.