Research has revealed that drinking tea and coffee may significantly reduce the risk of dementia. A large-scale study conducted by experts at Harvard University found that individuals who consume these caffeinated beverages exhibit better mental skills compared to non-drinkers. The study identified specific consumption levels linked to lower dementia risk, suggesting that moderate intake of both drinks could be beneficial.
The research involved tracking data from 131,000 health workers across the United States over an average of 43 years. Participants included 86,000 female nurses and 45,000 male health professionals. They completed dietary questionnaires every two to four years, which included questions about their consumption of caffeinated coffee, decaffeinated coffee, and tea. Cognitive tests were also administered throughout the study period.
During the follow-up, researchers identified 11,033 cases of dementia. The analysis indicated that higher intake of caffeinated coffee was significantly associated with a lower risk of dementia. Those who consumed the highest amount of coffee had an 18% reduced risk compared to those who drank the least. Similarly, tea drinkers showed a 16% reduction in risk. Furthermore, participants who consumed the most tea and coffee demonstrated a slower rate of cognitive decline than those with lower consumption levels.
Among the nurses surveyed, higher levels of caffeinated coffee consumption correlated with improved cognitive performance. The findings were consistent for tea consumption as well, but drinking decaffeinated coffee did not show a similar association with lower dementia risk or better cognitive function.
The authors noted that the most pronounced association was found among individuals who consumed a moderate amount of tea or coffee. They estimated that drinking around two to three cups of caffeinated coffee daily or one to two cups of tea daily was linked to the lowest dementia risk when compared to non-consumers. “Greater consumption of caffeinated coffee and tea was associated with lower risk of dementia and modestly better cognitive function, with the most pronounced association at moderate intake levels,” they stated in their article published in JAMA.
Lead author Yu Zhang from the TH Chan School of Public Health at Harvard University emphasized the importance of identifying modifiable lifestyle factors linked to dementia risk. “Dementia is one of the most important and challenging public health problems worldwide, and there are still very limited effective treatments,” Zhang explained. “We found that higher intake of caffeinated coffee and tea was associated with a lower risk of dementia and better cognitive performance.”
While the results are promising, experts have cautioned against assuming a direct cause-and-effect relationship. Dr. Susan Kohlhaas, executive director of research at Alzheimer’s Research UK, noted that the study shows an association rather than definitive proof that coffee or tea protect the brain. She highlighted potential confounding factors, stating, “People who drink coffee or tea may also differ in other ways that affect brain health.”
Professor Tara Spires-Jones, division lead at the UK Dementia Research Institute, acknowledged the study’s strengths but pointed out its limitations. She explained that observational research cannot conclusively determine whether caffeine intake causes a lower dementia risk. Other factors related to coffee and tea-drinking habits could influence the findings.
Additionally, the data on caffeine intake were based on self-reported questionnaires administered every two to four years. If participants were in the early stages of dementia, they might struggle to accurately report their consumption. Early brain changes could also affect their caffeine intake behavior.
As research continues, the findings underscore the potential health benefits of moderate tea and coffee consumption. Further investigations may provide deeper insights into the relationship between these beverages and cognitive health.
