Scientists from Niigata University and other institutions have found that higher coffee and caffeine intake may be linked to a reduced risk of dementia.
Dementia is a group of cognitive and social symptoms that interfere with daily functioning.
Rather than a single disease, it describes a range of conditions characterized by impairment in at least two brain functions, such as memory, judgment, language, or reasoning.
Common symptoms include forgetfulness, reduced social skills, and declines in thinking abilities severe enough to disrupt everyday activities.
Green tea and coffee share several health benefits, including a high content of antioxidants. Caffeine, a natural stimulant found in both beverages, can increase attention and alertness and may enhance mental performance, including reasoning speed and memory.
Although coffee, green tea, and caffeine have been proposed as potential protective factors against dementia, evidence from previous studies has remained inconclusive.
In the current study, researchers aimed to examine the associations between coffee, green tea, and caffeine intake and the risk of developing dementia in middle-aged and older adults. The study followed more than 13,000 community-dwelling participants aged 40 to 74 years for approximately eight years. Participants reported their coffee and tea consumption using a food frequency questionnaire.
The primary outcome was incident dementia, identified through records from Japan’s long-term care insurance database. During the follow-up period, 309 cases of dementia were recorded.
The researchers found that higher coffee consumption was associated with a lower risk of dementia. Compared with participants who consumed the least amount of coffee, those with the highest intake had a significantly reduced risk. Similarly, higher caffeine consumption was linked to a lower dementia risk.
These associations were strong in men but not observed in women. In addition, participants who consumed 2 to 2.9 cups per day and those who consumed three or more cups per day had a lower dementia risk compared with individuals who did not drink coffee.
The study also found that the association between green tea intake and reduced dementia risk was significant only among participants aged 60 to 69 years.
Based on these findings, the researchers suggest that higher levels of coffee and caffeine intake are strongly associated with a reduced risk of dementia, particularly in men. Notably, coffee consumption of three or more cups per day was linked to an approximately 50% reduction in dementia risk.
The study was published in Journal of the American Geriatrics Society and was conducted by Nana Matsushita and colleagues.
