Regular consumption of caffeinated coffee was associated with lower dementia rates and better cognitive outcomes in a study of U.S. adults followed for up to 43 years. The findings identify a relationship but do not establish that coffee prevents dementia.
Researchers recorded 141 dementia cases per 100,000 people annually among participants who consumed higher amounts of caffeinated coffee, compared with 330 cases among those who rarely or never drank it. Dementia involves declines in memory, thinking and other abilities that interfere with daily life.
Participants with higher caffeinated coffee intake also reported fewer concerns about declining cognition. Subjective cognitive decline was reported by 7.8% of this group, compared with 9.5% among those consuming little or none. These reports reflect perceived changes and do not necessarily indicate dementia.
The strongest associations appeared among people drinking two to three cups of caffeinated coffee daily. The relationship was observed across different levels of genetic risk for dementia. Higher consumption did not appear to offer additional benefits.
Tea consumption was also associated with lower dementia risk and better cognitive functioning, with the strongest associations at one to two cups daily. However, researchers did not distinguish between caffeinated and noncaffeinated tea, limiting conclusions about caffeine’s possible role.
Decaffeinated coffee did not show the same associations as caffeinated coffee. That difference raises questions about whether caffeine contributes to the findings, but does not demonstrate that it is responsible.
Other differences between people who drink coffee and those who avoid it could help explain the results. Genetics, general health and lifestyle are also relevant to dementia risk.
Overall, the study links moderate caffeinated coffee and tea consumption with more favorable measures of cognitive aging. Further research is needed to determine whether these beverages directly affect dementia risk and which components, if any, account for the observed associations.