Moderate, regular consumption of caffeinated coffee or tea may be associated with a reduced risk of dementia, according to a new study published in in the journal JAMA. The research, which followed over 130,000 individuals for decades, suggests a potential protective effect of caffeine on cognitive function.
Researchers analyzed data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, encompassing over 131,821 participants. The findings indicate that those who consumed two to three cups of caffeinated coffee daily had an 18% lower risk of developing dementia compared to those who consumed little to no caffeinated coffee. A similar benefit was observed with one to two cups of tea per day.
The Role of Caffeine
The study’s lead author, Dr. Yu Zhang, a research trainee at Mass General Brigham in Boston, emphasized that the research doesn’t recommend that non-coffee drinkers start consuming the beverage. Rather, the results are reassuring for those who already enjoy coffee as part of their routine. The protective effect appears to be specific to caffeinated beverages; decaffeinated coffee did not demonstrate the same benefits.
“When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention—and our unique access to high quality data through studies that has been going on for more than 40 years allowed us to follow through on that idea,” said senior author Daniel Wang, MD, ScD, associate scientist with the Channing Division of Network Medicine in the Mass General Brigham Department of Medicine and assistant professor at Harvard Medical School. He cautioned, however, that the effect size is small and that numerous factors contribute to cognitive health as we age.
The long-term observational nature of the study—spanning from 1980 to 2023—provides a robust dataset for examining the relationship between caffeine intake and dementia risk. Participants regularly completed diet questionnaires, allowing researchers to track their consumption habits over many years. After a median follow-up period of nearly 37 years, over 11,000 individuals had been diagnosed with dementia.
Observational Study and Limitations
It’s important to note that this study is observational, meaning it cannot definitively prove a cause-and-effect relationship between coffee/tea consumption and reduced dementia risk. While the data suggests an association, other factors—such as genetics, lifestyle, and overall health—could also play a role. Researchers acknowledge that the observed effect is modest, and further research is needed to fully understand the underlying mechanisms.
The study participants consisted of health professionals, primarily women (from the Nurses’ Health Study) and men (from the Health Professionals Follow-Up Study), with average ages of 46 and 54, respectively, at the start of the study. This demographic may not be fully representative of the general population, potentially limiting the generalizability of the findings.
Implications for Dementia Prevention
Dementia is a growing public health concern, and current treatments offer limited benefit, particularly once symptoms appear. This research highlights the potential importance of preventative strategies, including lifestyle factors like diet. While coffee and tea are not a guaranteed solution, they may represent a simple and accessible component of a brain-healthy lifestyle.
The findings align with existing research suggesting that certain lifestyle habits can influence brain health. Just as adequate sleep is crucial for cognitive function, caffeine appears to modulate the body’s response to aging and potentially slow cognitive decline. Researchers emphasize that a holistic approach to brain health, encompassing diet, exercise, and mental stimulation, is likely to be most effective.
While the study did not find negative effects from higher doses of caffeine, it’s always prudent to consume caffeine in moderation as part of a balanced diet. Individuals with underlying health conditions should consult with their healthcare provider regarding appropriate caffeine intake.
The evidence from this study strengthens the case for considering coffee and tea as potentially beneficial components of a dementia-preventative lifestyle. Further research, including clinical trials, will be necessary to confirm these findings and elucidate the precise mechanisms by which caffeine may protect against cognitive decline.
