Coffee & Dementia Risk: Moderate Intake Linked to Better Cognitive Function

Moderate consumption of caffeinated coffee may be associated with a reduced risk of developing dementia and improved long-term cognitive performance, according to a large scientific study published in February 2026 in the journal JAMA. The study followed more than 131,000 adults in the United States for over four decades.

The research, titled ‘Coffee and Tea Intake, Dementia Risk, and Cognitive Function,’ analyzed in detail the relationship between coffee intake – both with and without caffeine – tea, and the risk of dementia, as well as various indicators of cognitive function. A key finding is that the protective effect is particularly pronounced in those who consume between two and three cups of caffeinated coffee daily.

The study was developed from two large population follow-up cohorts: the Nurses’ Health Study, which included 86,606 women followed between 1980 and 2023, and the Health Professionals Follow-up Study, with 45,215 men monitored between 1986 and 2023. None of the participants had a diagnosis of cancer, Parkinson’s disease, or dementia at the start of the follow-up period.

Over a maximum follow-up period of 43 years – with a median of approximately 37 years – 11,033 incident cases of dementia were documented, identified through death records and medical diagnoses. Throughout the study, researchers collected dietary information every two to four years using validated questionnaires, allowing for a precise analysis of coffee and tea consumption patterns over time.

After adjusting for potential confounding factors and combining the results from both cohorts, the authors found that individuals in the highest quartile of caffeinated coffee consumption had an 18% lower risk of dementia compared to those in the lowest quartile. In absolute terms, this translated to 141 cases per 100,000 person-years in the highest consumption group, compared to 330 cases in the lowest consumption group.

The positive impact wasn’t limited to the clinical diagnosis of dementia. The study also evaluated subjective cognitive decline, measured through a questionnaire assessing personal perceptions of memory and thinking problems. In this indicator, 7.8% of people with the highest caffeinated coffee consumption reported cognitive decline, compared to 9.5% in the lowest consumption group.

in the case of the women from the Nurses’ Health Study, telephone-based neuropsychological tests were performed to measure objective cognitive function. Those who consumed more caffeinated coffee scored slightly higher on the Telephone Interview for Cognitive Status (TICS), a widely used test to assess mental status, as well as on a global measure of cognition integrating six different tests. Although the difference in global cognition did not reach statistical significance, the trend was consistent with the other results.

The analysis also included tea consumption, which showed similar associations with a lower risk of dementia and better cognitive outcomes, especially with an intake of one to two cups per day. In contrast, decaffeinated coffee did not show a significant relationship with either reduced dementia risk or improved cognitive performance, a finding that reinforces the hypothesis that caffeine plays a central role in the observed effects.

A key aspect of the study was the dose-response analysis. Researchers identified an inverse non-linear relationship between caffeinated coffee consumption and dementia risk, meaning that the benefit does not increase indefinitely with larger quantities. Instead, the most pronounced effects were concentrated at moderate consumption levels, particularly in the range of two to three cups daily.

In their conclusions, the authors note that greater consumption of caffeinated coffee and tea is associated with a lower risk of dementia and modestly more favorable cognitive outcomes. While they emphasize that Here’s an observational study – and not a clinical trial – they highlight that the duration of follow-up, the sample size, and the differentiation between caffeinated and decaffeinated coffee strengthen the robustness of the findings.

“While our results are encouraging, it’s important to remember that the effect size is small and You’ll see lots of important ways to protect cognitive function as we age,” said Daniel Wang, associate scientist with the Channing Division of Network Medicine in the Mass General Brigham Department of Medicine and assistant professor at Harvard Medical School. “Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”

The work provides new evidence to a scientific debate that has been inconclusive for years and suggests that, at least from a population perspective, moderate consumption of caffeinated coffee could be part of habits associated with healthier cognitive aging.