New research suggests a simple dietary habit – enjoying two to three cups of caffeinated coffee daily, or one to two cups of tea – may be associated with a reduced risk of dementia, slowed cognitive decline, and preserved brain function. The findings, published , in the journal JAMA, add to a growing body of evidence exploring the potential neuroprotective benefits of these widely consumed beverages.
The large-scale prospective cohort study analyzed data from 131,821 participants drawn from the Nurses’ Health Study and the Health Professionals Follow-Up Study, spanning over four decades of observation. Researchers, led by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard, meticulously tracked participants’ dietary habits, including coffee and tea consumption, alongside their cognitive health outcomes.
“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.
The study revealed that individuals who consistently consumed moderate amounts of caffeinated coffee demonstrated an 18% lower risk of developing dementia compared to those with lower intake. Specifically, for every 100,000 people, there were 141 cases of dementia in the group consuming the most coffee, compared to 330 cases in the group consuming the least. This association was particularly noticeable among individuals .
Interestingly, the protective effect appeared to be specific to caffeinated coffee and tea. Decaffeinated coffee did not show the same association with reduced dementia risk. The study also noted a trend toward better performance on cognitive tests, specifically memory and concentration, among those who regularly consumed caffeinated coffee, although this finding was more pronounced in women participating in the Nurses’ Health Study.
While the study highlights a compelling link, researchers emphasize that it does not establish a causal relationship. “Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle,” Wang explained, adding that “the effect size is small and You’ll see lots of important ways to protect cognitive function as we age.”
The findings align with emerging research exploring the biological mechanisms by which coffee and tea may benefit brain health. Recent investigations suggest that compounds found in coffee, such as antioxidants and anti-inflammatory agents, may help protect brain cells from damage and improve metabolic regulation. A study published in BMJ Mental Health last November found that regular consumption of three to four cups of coffee daily was associated with longer telomere length, a marker of younger biological age, in adults with serious mental disorders. Similarly, research in the European Journal of Nutrition indicated that four to six cups of coffee a day may be linked to a lower risk of frailty in individuals over 55.
Green tea, too, has shown promise in supporting cognitive health. A study published in the journal Science of Food found that consuming three or more cups of green tea daily was associated with fewer lesions in the brain’s white matter, a risk factor for cognitive decline.
Experts caution against interpreting these findings as a recommendation to start drinking coffee or tea if you don’t already. “We are not recommending that people who don’t drink coffee start drinking,” stated Dr. Yu Zhang, a research trainee at Mass General Brigham and lead author of the study. “We are just seeing that for people who already drink coffee, the results are really reassuring.”
Regulatory bodies, such as the FDA and the American Heart Association, consider moderate caffeine consumption – up to three cups of coffee per day – to be generally safe. However, individual sensitivity to caffeine varies, and excessive intake can lead to adverse effects.
the researchers emphasize that maintaining a healthy lifestyle, encompassing a balanced diet, regular exercise, and cognitive stimulation, remains the most effective strategy for preserving brain health and reducing the risk of dementia. These findings add to the growing understanding of how dietary factors can play a role in supporting cognitive function, but should be considered as one component of a comprehensive approach to brain health.
