Coffee and Tea Linked to Lower Dementia Risk

Research indicates that people who enjoy a couple of cups of tea or coffee daily might reduce their risk of dementia and experience better cognitive performance compared to those who don’t consume these beverages.

Analyzing health records from over 130,000 individuals, the study found that participants who typically drank two to three cups of caffeinated coffee or one to two cups of caffeinated tea each day had a 15-20% lower risk of developing dementia over 40 years compared to non-drinkers.

Interestingly, those who preferred caffeinated coffee appeared to experience less cognitive decline than decaf drinkers and performed slightly better on various cognitive tests. These findings were shared in a report from the Journal of the American Medical Association.

While this suggests that regular tea and coffee consumption could benefit brain health, the research isn’t definitive. There may be other factors at play; for instance, individuals who struggle with sleep might avoid caffeine to improve their rest, and this group could also be at an increased risk for cognitive decline.

Lead author Yu Zhang, from Harvard’s nutritional epidemiology department, points out that while their study doesn’t establish a direct cause-and-effect relationship, it represents some of the most convincing evidence regarding coffee and tea intake and cognitive health.

Caffeine and polyphenols found in these drinks have potential protective effects against brain aging—they might enhance vascular health and reduce inflammation. Caffeine’s connection to lower rates of type 2 diabetes, a known risk factor for dementia, adds another layer of interest here.

The team assessed data from 131,821 volunteers involved in two significant public health studies, the Nurses’ Health Study and the Health Professionals Follow-Up Study. Participants underwent repeated assessments regarding their diets, dementia diagnoses, cognitive decline, and performance on cognitive tests over many years.

Those consuming the most caffeinated coffee exhibited an 18% lower risk of dementia compared to light or non-consumers, with similar results observed for tea drinkers. This protective effect seemed to plateau at around two to three cups of coffee or one to two cups of tea daily. Notably, no link was found between decaffeinated coffee and dementia risk.

Further investigation is necessary to establish whether these two drinks truly offer brain protection. Conducting randomized trials over several decades, assigning participants to caffeinated versus decaffeinated beverages, is difficult in practice. However, researchers could focus on whether these drinks lead to biological changes that indicate better brain function, possibly visible through scans.

Naveed Sattar, a professor of cardiometabolic medicine at the University of Glasgow, acknowledged that understanding these relationships can be complicated, especially since caffeine has both positive and negative effects on the brain.

Both coffee and tea contain antioxidants that may offer benefits, and caffeine can enhance motivation for work, learning, and exercise. However, for some individuals, caffeine may elevate blood pressure, which has been identified as a significant factor linked to dementia. Sattar noted that caffeine’s varied effects mean that its overall impact can be unclear until properly studied in controlled trials.

Researchers advocate that about half of global dementia cases could be delayed or prevented through addressing various risk factors, including obesity, smoking, excessive alcohol use, hearing loss, and high blood pressure.

Zhang cautioned against viewing coffee or tea as a “magic shield,” emphasizing the importance of a healthy lifestyle, regular exercise, a balanced diet, and good sleep for maintaining optimal brain health.