Coffee and Tea Consumption Linked to Lower Dementia Risk, Study Finds

A large-scale study published in February 2026 in JAMA provides compelling evidence that regular consumption of caffeinated coffee or tea is associated with a reduced risk of dementia and improved cognitive function. The research, which followed over 130,000 individuals for more than 40 years, suggests that moderate caffeine intake could be a valuable component of a preventative strategy against cognitive decline.

Key Findings of the Study

Researchers analyzed data from the Nurses’ Health Study and the Health Professionals Follow-Up Study, finding a significant correlation between caffeine intake and dementia risk. Key findings include:

• Individuals with the highest intake of caffeinated coffee demonstrated an 18% lower risk of dementia compared to those who consumed little to no caffeine. Mass General Brigham
• The protective effect was observed specifically with caffeinated coffee, suggesting that caffeine is the primary driver of this benefit.
• Optimal benefits were seen with moderate consumption: 2-3 cups of coffee per day or 1-2 cups of tea per day. Harvard Gazette
• The study’s findings remained consistent regardless of genetic predisposition, including the presence of the APOE4 gene.

How Caffeine May Protect the Brain

While the exact mechanisms are still being investigated, researchers believe caffeine may offer neuroprotective benefits through several pathways:

• Reducing Amyloid Plaque Accumulation: Caffeine may help limit the buildup of amyloid plaques, a hallmark of Alzheimer’s disease.
• Improving Insulin Sensitivity: Caffeine can enhance insulin sensitivity, which is crucial for brain health.
• Reducing Neuroinflammation: Caffeine possesses anti-inflammatory properties that can protect against neuroinflammation, a key contributor to cognitive decline.

The Importance of Moderate Consumption

The study emphasizes a “non-linear” relationship between caffeine intake and cognitive benefits. Consuming excessive amounts of coffee or tea did not provide additional protection and could potentially be counterproductive due to sleep disruption or increased anxiety. JAMA Network

Study Details and Scope

The prospective cohort study involved 131,821 participants from the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS). Over the course of the study, 11,033 participants developed dementia. The research was led by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard.

Looking Ahead

While the findings are encouraging, researchers caution that the effect size is modest and that coffee or tea consumption should be considered one piece of a broader strategy for protecting cognitive function. Early prevention remains crucial, as current dementia treatments offer limited benefits once symptoms appear. Further research is needed to fully understand the long-term effects of caffeine on brain health and to identify optimal consumption levels for different individuals.

Key Takeaways

• Moderate consumption of caffeinated coffee (2-3 cups daily) or tea (1-2 cups daily) is associated with a lower risk of dementia.
• Caffeine appears to be the primary neuroprotective agent in coffee.
• The benefits are observed regardless of genetic predisposition.
• Excessive caffeine intake does not provide additional benefits and may have negative consequences.