There’s a reason many of us wake up by sipping on a good cup of coffee of tea. The drinks promote alertness and seemingly kickstart a tired brain. While that’s certainly helpful in the moment, a new February 2026 study published in the medical journal JAMA indicates those habits might have long-term cognitive benefits, too.

The study, conducted by researchers with connections to Harvard Medical School and the Chan School of Public Health at Harvard University, looked at the habits of thousands of healthcare workers. While there are plenty of studies that tout the benefits of coffee, this one stands out for its length. Researchers have been tracking the caffeine intake of doctors, nurses, and other healthcare professionals for decades via the Nurses’ Health Study and Health Professionals Follow-Up Study, some as long as 43 years.

Over that time, researchers compiled and analyzed information on dementia diagnoses and cognitive decline, as well as how many cups of regular or decaf coffee and tea participants drank. And the results suggest good news for people who can’t get enough java: the top 25% of coffee drinkers were significantly less likely to receive a dementia diagnosis by the end of the study compared to their peers who drank less coffee or tea.

Ultimately, the results showed that people who drink coffee and tea daily are at less risk of developing dementia than people who skip the morning cup of joe. The study followed over 131,000 participants—11,033 of whom had dementia by the end of the research.  The people who drank the most coffee and tea had the lowest rates of the disease—about 141 cases in 100,000. It’s a staggering difference between them and the healthcare professionals who drank the least coffee and tea, who had a rate of about 330 per 100,000.

In an interview with the Harvard Gazette, lead author Yu Zhang, a student at Harvard’s Chan School of Public Health and research trainee at Mass General Brigham, explained that the benefits of coffee and tea seemed to extend even to people in higher risk groups. He says, “We also compared people with different genetic predispositions to developing dementia and saw the same results—meaning coffee or caffeine is likely equally beneficial for people with high and low genetic risk of developing dementia.”

The research also differentiated between regular and decaf coffee, while many other studies lump the brew into a singular category. The level of caffeine in your cup is evidently important, as participants who drank only decaf were just as likely to receive a dementia diagnosis as groups who drank the least coffee or tea. Only caffeinated coffee and tea seem to reduce the risk of dementia, with researchers concluding that a “higher caffeinated coffee intake was significantly associated with lower risk of dementia.”

The presence of “bioactive compounds,” such as caffeine or polyphenols, are credited as the source of the brain-boosting benefits. As defined by the National Cancer Institute, bioactive compounds “have actions in the body that may promote good health.” Harvard further explains that they are “possible neuroprotective factors that reduce inflammation and cellular damage while protecting against cognitive decline.”

To get the most benefit, the researchers suggests drinking two to three cups of caffeinated coffee or one to two cups of tea per day. If your habit outpaces that amount, don’t worry. The study pointed out that drinking more coffee than the suggested amount does not significantly increase or decrease the rates of dementia.

“While our results are encouraging, it’s important to remember that the effect size is small and there are lots of important ways to protect cognitive function as we age,” says Daniel Wang, MD, ScD, senior author and associate scientist with the Channing Division of Network Medicine at the Mass General Brigham Department of Medicine, adding that the study “suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”

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Rachel Maidl
Rachel Maidl is a writer and editor with over a decade of experience in the Milwaukee area. She’s currently a contributing editor for The Healthy and served as senior editor for Birds & Blooms magazine. Before joining Trusted Media Brands, Rachel worked as a communications manager for a medical nonprofit, helping allergists and immunologists ...
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Rachel Maidl