A large-scale study conducted in the United States has identified a potential association between moderate daily consumption of coffee and tea and a lower risk of developing dementia. The research, led by scientists from Mass General Brigham, the Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard, analysed long-term health data and has been published in the peer-reviewed journal JAMA.
The investigation explored whether regular intake of caffeinated beverages could influence cognitive ageing. According to the findings, individuals who consumed approximately two to three cups of coffee per day or one to two cups of tea demonstrated a reduced likelihood of developing dementia. Additionally, moderate consumption appeared to slow subjective cognitive decline and support overall cognitive performance.
Long-Term Population Data Strengthens Findings
The study utilised data collected from two major longitudinal research projects in the United States — the Nurses’ Health Study and the Health Professionals Follow-Up Study. These initiatives have tracked participants’ health, diet, and lifestyle habits for several decades, providing researchers with a rare opportunity to evaluate patterns over extended periods. Participants were monitored for up to 43 years, with repeated assessments examining dietary intake, cognitive function, and dementia diagnoses.
Among more than 130,000 participants included in the analysis, over 11,000 cases of dementia were recorded. Researchers observed that both male and female participants who regularly consumed caffeinated coffee had an approximately 18 per cent lower risk of developing dementia when compared with individuals reporting little or no coffee intake. Moreover, those who consumed caffeinated coffee reported fewer early symptoms related to perceived memory or cognitive decline.
Tea consumption produced similar patterns, reinforcing the hypothesis that caffeinated beverages may play a protective neurological role. However, decaffeinated coffee did not demonstrate comparable benefits, suggesting that caffeine itself may be a key component influencing cognitive health outcomes.
Bioactive Compounds May Support Brain Health
Coffee and tea contain several biologically active compounds, including caffeine and polyphenols, which have been investigated for their potential neuroprotective properties. Scientific literature suggests these compounds may help reduce inflammation and oxidative stress, both of which are mechanisms associated with cellular damage and neurological deterioration.
Researchers involved in the United States study emphasised that dementia prevention remains a major global health priority. Current therapeutic interventions often provide limited benefits once clinical symptoms appear, highlighting the importance of identifying lifestyle-related protective factors earlier in life.
Optimal Intake Levels and Genetic Considerations
The study found that cognitive benefits were most evident among individuals consuming moderate quantities of caffeinated beverages. Interestingly, higher levels of caffeine intake did not demonstrate harmful neurological effects within the observed data, and in some cases produced protective outcomes similar to moderate consumption levels.
Further analysis explored whether genetic susceptibility influenced the relationship between caffeine intake and dementia risk. The researchers reported that the association between caffeinated beverage consumption and reduced dementia risk remained consistent across individuals with varying genetic predispositions to the condition.
A Potential Preventive Strategy — With Limitations
Despite the encouraging results, scientists caution that the protective effect identified is modest. They stress that maintaining cognitive health is multifactorial, involving elements such as physical activity, balanced nutrition, cardiovascular health, and social engagement.
The research conducted in the United States contributes to an expanding body of scientific evidence suggesting that dietary habits may influence long-term neurological health. Nevertheless, researchers emphasise the need for additional studies to clarify the biological mechanisms responsible and to determine how these findings may translate into clinical recommendations.
While moderate coffee and tea consumption may represent a promising component of dementia prevention strategies, healthcare professionals continue to advise individuals to consider caffeine intake within the context of overall health and personal tolerance levels.