Daily coffee consumption has been linked to lower risks of dementia.

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Daily coffee consumption, if caffeinated, may be linked to lower risks of dementia in older adults. A study published in the February 2026 issue of the Journal of the American Medical Association reviewed data from over 100,000 adults over a period of four decades. The investigators, based at Harvard Medical School and the T.H. Chan School of Public Health at Harvard, looked at females enrolled in the Nurses Health Study between 1980 and 2023 (over 86,000 individuals) and men enrolled in the Health Professionals Follow-Up Study from 1986-2023 (over 45,000 individuals).

The group looked at three lifestyle factors, including consumption of caffeinated coffee, decaffeinated coffee and tea, and amassed dietary data every two to four years for each enrolled member in these studies. They then looked at both objective measures of dementia as well as subjective reports of cognitive decline for each subject.

The most common cause of dementia in the U.S. is Alzheimer’s Disease, which usually first presents with subjective cognitive decline and progresses to more objective deficits in memory and ability to perform activities of daily living. Over 6 million people in this country are living with Alzheimer’s, and this is likely to rise to 13 million over the next two decades. Factors such as continuing to engage in learning activities, exercise, social connections, getting adequate sleep and minimizing alcohol intake and use of sedatives have all been linked to reduced likelihood of developing dementia later in life.

Coffee and caffeinated tea consumption have been linked to some reduction in high blood pressure, heart failure and all-cause cardiovascular mortality, but has an unclear association with an increased risk of coronary artery disease and cognitive function. An ongoing placebo-controlled multi-center randomized double-blind trial, based at the University of Lille in France, is looking at patients with very early signs of declining cognition and early Alzheimer’s Disease. Enrolled patients are either given a placebo capsule or a capsule containing 200mg of caffeine (equivalent to two cups of coffee) twice per day, for a total of 400mg per day, over a 30-week period. Participants will then undergo cognitive testing to assess for any caffeine-specific impacts.

The current JAMA study included participants already enrolled in long term health outcomes studies, and found a notable correlation between caffeinated coffee consumption and better cognitive function. For both groups, the development of dementia was reduced by over half, and the presentation of subjective cognitive decline reduced from 9.5% to 7.8%. The tea consumers reported similar benefits to caffeinated coffee drinkers. Those who consumed decaffeinated coffee found no reduction in dementia risk or subjective cognitive decline.

The researchers also found a limit to the benefits of caffeinated coffee, peaking at about two to three cups per day. The benefits plateaued with daily consumption of more than two or three cups. There were no specific details on how the consumed coffee was prepared, whether freshly ground, instant or whole bean, as well as brewing technique or caffeine concentration per cup. In addition, type of tea, caffeinated or not, was also not specified. Moreover, even with large population studies over several decades, association as opposed to causation remain hard to differentiate. These particular study populations included health professionals only, which may have both positive and negative impacts on subjects’ responses and outcomes data.

But at least for now, the data is pointing towards some benefits, and likely no risks, to drinking real coffee, or tea. But to keep sleep quality solid, best to consume any caffeinated substance in the early part of the day.