Daily Coffee and Tea Consumption Linked to Reduced Dementia Risk in Major Study
Coffee and tea enthusiasts have reason to celebrate. A comprehensive long-term study examining dietary habits and cognitive function has revealed that consuming moderate daily amounts of these popular caffeinated beverages is significantly associated with a lower risk of developing dementia.
Study Details and Participant Demographics
The research, published in the Journal of the American Medical Association, tracked more than 131,000 participants in the United States who were free from cancer, Parkinson’s disease, and dementia at the study's outset. This extensive cohort included over 86,000 female participants from the Nurses’ Health Study, monitored from 1980 to 2023, and more than 45,000 male participants from the Health Professionals Follow-up Study, followed from 1983 to 2023.
Female participants entered the study at an average age of 46, while male participants averaged 54 years old. To assess the relationship between coffee, tea, and cognitive health, researchers gathered food frequency questionnaires from participants every two to four years throughout the study period.
Key Findings on Cognitive Health
Among the participants, more than 11,000 cases of dementia were recorded. The analysis demonstrated that higher intake of caffeinated coffee was significantly linked to a reduced dementia risk and a lower prevalence of subjective cognitive decline. Increased coffee consumption was also associated with improved objective cognitive performance in the Nurses’ Health Study group.
Similarly, greater consumption of caffeinated tea was connected to comparable positive cognitive outcomes. Researchers identified the most substantial association with lower dementia risk and reduced cognitive decline in participants who consumed moderate levels—specifically, approximately 2 to 3 cups of caffeinated coffee or 1 to 2 cups of tea per day.
Individuals with the highest daily coffee intake exhibited an 18% lower risk of developing dementia compared to those with the lowest intake. The results for caffeinated tea drinkers were analogous. Notably, decaffeinated coffee showed no association with reduced dementia risk or enhanced cognitive performance.
Expert Insights and Cautions
Yu Zhang, a lead author of the study from the Harvard T.H. Chan School of Public Health, emphasized that the research does not establish a direct causal link between caffeine and dementia risk reduction. "Our study alone can’t prove causality, but to our knowledge, it is the best evidence to date looking at coffee and tea intake and cognitive health, and it is consistent with plausible biology," Zhang told The Guardian.
Zhang advised against viewing coffee or tea as a magic shield against cognitive decline. "I’d say maintaining a healthy lifestyle, getting regular exercise, having a balanced diet and getting good sleep are all important to get better brain health," he added.
Dr. Kellyann Niotis, a preventive neurologist not involved in the study, highlighted the complexity of isolating coffee's effects. "It’s really a big challenge to disentangle the effects of coffee as a whole from all of the other compounds that are also in coffee—and tea," she told NBC News. "It’s definitely possible that these other compounds are interacting with each other, or synergistically with the caffeine itself, to exert some benefit."
Broader Context on Dementia Prevention
Research underscores that physical and mental activities are crucial in diminishing dementia risk, with diet playing a significant role. For instance, a study in the journal Neurology last year found that consuming processed red meat was associated with a higher likelihood of dementia or cognitive decline.
Dr. Andy Liu, an associate professor of neurology at the Duke University School of Medicine, previously stressed to HuffPost that a healthy diet combined with physical exercise is advantageous for cognitive health. He often recommends the Mediterranean diet to patients, particularly those with Alzheimer’s disease or cognitive concerns.
Liu also advised seeking medical advice promptly upon noticing cognitive changes. "Seeing us earlier is very beneficial," he explained. "Even if we don’t see anything, we tell them to come back and we’ll continue to monitor them, which is much safer. And then we can take action if we do notice changes."
