What to know about a new study on coffee, tea, caffeine and dementia risk
A long-term analysis shows that people who drink caffeinated coffee and tea have a lower risk of developing dementia, although the study does not prove cause and effect.
Dr. Céline Gounder, CBS News medical contributor and editor-at-large for public health at KFF Health News, warned that the results should be taken "with a massive grain of salt."
The research, published in the medical journal JAMA on Monday, analyzed data on 131,821 people who had participated in two studies that ran from 1986 to 2023. Of that group, 11,033 developed dementia during the period studied.
The researchers compared each participant's self-reported intake of coffee, caffeinated tea and decaffeinated coffee, and tracked records of their cognitive health over time. They found that men and women who drank the most caffeinated coffee had an 18% lower risk of dementia when compared to those who reported little or no caffeinated coffee consumption. Caffeinated coffee drinkers also showed a lower prevalence of cognitive decline, the researchers said.
The benefits appeared to be most pronounced in people who drank two to three cups of caffeinated coffee a day, the researchers said, or one to two cups of caffeinated tea.
"Higher caffeinated coffee intake was significantly associated with lower risk of dementia," they wrote. "Decaffeinated coffee intake was not significantly associated with dementia risk.
However, Gounder said the research only found a small reduction in risk, and she pointed out that the data showed an association, not proof of causation, meaning that the caffeinated beverages might not be the only factor involved. The paper's authors noted that more research was necessary to validate their results.
"Studies like this drive me nuts," Gounder said on "CBS Mornings."
"People want permission to do the things they're already doing, or that they want to be doing, and it's usually really common behaviors like red wine or coffee or chocolate," Gounder said. "And it's usually something very simple that's related to a high-risk outcome like dementia."
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Gounder noted there may be other underlying factors that affected people's dementia risk, not just their coffee consumption. For example, some people may avoid caffeinated beverages for other health reasons, like high blood pressure, which is a known risk factor for dementia. The researchers said they excluded people with major chronic diseases at the outset of the study to try to account for that.
The Alzheimer's Association says more than 7 million Americans are living with Alzheimer's disease, the most common cause of dementia.
Gounder said people should not change their diets based on the research, but there are some steps that can help reduce the risk.
"Now, what should you be doing to prevent dementia? Exercise, improve your diet, address weight loss," she said, adding that hearing loss is also a warning sign of dementia risk. "Things that we don't like, things that are boring."
The research published Monday included "43 years of follow-up with repeated dietary measurements and assessments of dementia, subjective cognitive decline, and objective cognitive function," according to the analysis. The research was conducted by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard.
