Coffee & Tea Linked to Lower Dementia Risk, Study Finds

Moderate, regular consumption of caffeinated coffee and tea may be associated with a reduced risk of developing dementia, according to a large, long-term study published February 9 in the Journal of the American Medical Association. The research, analyzing decades of data, suggests a potential protective effect, though the precise mechanisms remain unclear.

The study followed over 130,000 individuals—participants in the Nurses’ Health Study and the Health Professionals Follow-up Study—who were free of cancer, Parkinson’s disease and dementia at the study’s outset, dating back to the 1980s. Participants completed detailed dietary questionnaires periodically, allowing researchers to track their intake of coffee and tea over many years. Dementia diagnoses were ascertained through death records and self-reporting.

Researchers observed an inverse relationship between caffeine intake and dementia risk. Specifically, individuals who consumed approximately two to three cups of caffeinated coffee daily, or one to two cups of tea, exhibited the lowest risk compared to those who abstained from these beverages. Higher levels of consumption did not appear to confer additional benefit. Notably, the study found no association between decaffeinated coffee and a reduced risk of dementia.

Among those who did not consume caffeinated coffee, the rate of new dementia cases was 330 per 100,000 person-years. This rate decreased to 229 per 100,000 person-years among moderate coffee consumers. While those who consumed the most coffee also showed a lower rate, statistical adjustments for factors like age and smoking habits revealed that both moderate and high consumption were associated with similar risk reductions—approximately 19 and 18 percent, respectively. Tea consumption also demonstrated a protective association, although the study did not differentiate between caffeinated and decaffeinated tea.

The study participants who consumed the most coffee tended to be younger and were more likely to have a history of smoking. These factors were carefully accounted for in the statistical analysis to isolate the effect of coffee and tea consumption.

While the study establishes an association, it does not prove causation. The researchers did not investigate the biological mechanisms underlying the observed relationship. However, they propose several potential pathways. Inflammation is known to play a role in the development of dementia, and previous research suggests that caffeine may possess anti-inflammatory properties. Both coffee and tea contain compounds that may mitigate oxidative stress, a process that causes cellular damage.

It’s important to note that dementia is a complex condition with multiple contributing factors, and diet is likely only one piece of the puzzle. The researchers emphasize that reducing dementia risk is unlikely to be as simple as increasing coffee or tea intake.

The findings add to a growing body of evidence suggesting potential cognitive benefits associated with moderate caffeine consumption. A recent study highlighted by Gizmodo, for example, also points to a potential link between daily coffee consumption and a lower risk of dementia. Similarly, a large Harvard study, as reported by ZME Science, found that both coffee and tea were significantly associated with a lower risk of dementia.

Further research is needed to elucidate the specific compounds responsible for these potential benefits and to determine the optimal level of consumption. Individuals with underlying health conditions or concerns about caffeine intake should consult with their healthcare provider.

This study underscores the importance of a holistic approach to brain health, encompassing a balanced diet, regular exercise, cognitive stimulation, and management of cardiovascular risk factors.