New research suggests that caffeinated coffee may help reduce the risk of dementia.
A long-term observational study involving nearly 132,000 healthy adults found that drinking two to three cups of caffeinated coffee or one to two cups of tea daily was associated with a lower risk of dementia, slower cognitive decline, and better preservation of cognitive function.
The findings were published Monday in the Journal of the American Medical Association.
Dr. Yu Zhang, a research intern at Brigham and Women’s Hospital in Boston and the study’s lead author, said the results were encouraging but cautioned against viewing coffee as a cure.
“We’re not recommending that people who don’t drink coffee start drinking coffee,” Zhang said. “For people who already drink coffee, we found that the results were really encouraging.”
The study found that decaffeinated coffee did not provide the same neuroprotective benefits.
Researchers from Mass General Brigham, Harvard T.H. Chan School of Public Health, and Broad Institute analyzed health and caffeine consumption data collected between 1980 and 2023.
The research drew on two major datasets:
-
The Nurses’ Health Study, which followed more than 86,000 women with an average age of 46.
-
The Health Professionals Follow-up Study, involving over 45,000 men with an average age of 54.
Participants completed dietary questionnaires every two to four years to track coffee, decaffeinated coffee, and tea consumption.
After a median follow-up of nearly 37 years, more than 11,000 participants were diagnosed with dementia.
The findings showed:
-
People who consumed the most caffeinated coffee had an 18% lower risk of dementia compared to those who drank the least.
-
Among tea drinkers, those with the highest consumption had a 14% lower risk.
-
The strongest protective association was observed in individuals aged 75 and younger.
Compared to non-drinkers, those who consumed two to three cups of caffeinated coffee or one to two cups of tea daily—equivalent to about 300 milligrams of caffeine—had the lowest risk.
The protective association appeared stronger among individuals at higher genetic risk of dementia, including those carrying the APOE4 gene, a major risk factor for Alzheimer’s disease.
However, Zhang emphasized that dementia is a complex condition that cannot be fully prevented through diet alone.
“Drinking coffee alone cannot provide a magical effect that can prevent people from developing dementia,” he said.
According to the World Health Organization, an estimated 57 million people worldwide were living with dementia in 2021. The condition disproportionately affects women, and Alzheimer’s disease remains the most common form.
