A new study conducted by researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard suggests that drinking 2-3 cups of caffeinated coffee or 1-2 cups of tea daily may significantly reduce the risk of developing dementia. The findings, published in JAMA, analyzed data from 131,821 participants in the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS).
According to the study, moderate consumption of these beverages not only lowered dementia risk but also slowed cognitive decline and preserved cognitive function. “When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention,” said senior author Daniel Wang, MD, ScD. “Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”
The Importance of Early Prevention
Early prevention is crucial in the fight against dementia, as current treatments offer limited benefits once symptoms manifest. This has led researchers to explore lifestyle factors, such as diet, that could influence dementia development. Coffee and tea, rich in bioactive compounds like polyphenols and caffeine, have been identified as potential neuroprotective agents.
These compounds are believed to reduce inflammation and cellular damage, thereby protecting against cognitive decline. However, previous studies have yielded inconsistent results due to limited follow-up and insufficient detail on long-term intake patterns. The comprehensive data from the NHS and HPFS, with follow-ups extending up to 43 years, provide a more detailed understanding of these potential benefits.
Key Findings and Implications
Of the over 130,000 participants, 11,033 developed dementia. The study found that those with the highest intake of caffeinated coffee had an 18% lower risk of developing dementia compared to those who consumed little or no caffeinated coffee. Additionally, coffee drinkers exhibited a lower prevalence of subjective cognitive decline and performed better on objective cognitive function tests.
“Both male and female participants with the highest intake of caffeinated coffee had an 18% lower risk of dementia compared with those who reported little or no caffeinated coffee consumption.”
Higher tea intake showed similar results, while decaffeinated coffee did not, suggesting that caffeine might be the key factor in these neuroprotective effects. Despite previous concerns, higher caffeine intake did not yield negative effects, instead offering similar benefits to the optimal dosage.
Genetic Factors and Broader Implications
The study also examined the impact of genetic predispositions on dementia risk. “We compared people with different genetic predispositions to developing dementia and saw the same results,” said lead author Yu Zhang, MBBS, MS, PhD student. This indicates that coffee or caffeine could be equally beneficial for individuals regardless of their genetic risk.
The implications of these findings are significant, suggesting that moderate coffee and tea consumption could be a simple, accessible strategy to help reduce dementia risk. However, as Dr. Wang cautions, “it’s important to remember that the effect size is small and there are lots of important ways to protect cognitive function as we age.”
Future Directions and Research
While the study provides promising insights, further research is needed to fully understand the mechanisms behind caffeine’s neuroprotective effects and to identify other contributing factors. The study was supported by various research grants from the National Institutes of Health, ensuring that the findings are robust and reliable.
As the global population ages, the demand for effective dementia prevention strategies will only increase. This study offers a potential pathway for further exploration, emphasizing the role of dietary choices in maintaining cognitive health.
For those interested in the detailed findings, the paper titled “Coffee and tea intake, dementia risk, and cognitive function” is available in JAMA under DOI: 10.1001/jama.2025.27259.
