The amount of caffeine a person consumes could influence their risk of Alzheimer’s disease or other forms of dementia, a new study found.
The research, published in August in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, is the first to find a strong association between caffeine consumption and the risk of dementia.
The research team found that participants who reported lower caffeine consumption had a greater risk of exhibiting memory loss consistent with Alzheimer's or mild cognitive impairment. People who drank less caffeine also had lower levels of a certain amyloid protein that is often associated with the development of Alzheimer’s disease.
Alzheimer’s disease, the most common type of dementia, affects an estimated 6.9 million Americans.
“Previous studies examining the association between caffeine consumption and the risk of dementia and Alzheimer’s disease have been varied,” Claire Sexton, DPhil, senior director of scientific programs and outreach at the Alzheimer’s Association, told Health. “Some studies have shown that caffeine may reduce the risk of dementia by a small amount, while others have shown no effect or a slightly increased risk.”
While the new study adds to our understanding of caffeine’s effects on the brain, it doesn’t necessarily suggest people should up their caffeine intake.
“It is important to recognize that caffeine can be consumed in a variety of ways, including coffee, tea, chocolate, and energy drinks,” Sexton said. “Some [of these have] high levels of sugars, artificial sweeteners, and other ingredients that may reduce any potential benefit of caffeine.”
Here’s what experts had to say about the new study, current theories on the connection between dementia and caffeine consumption, and ways to lower your risk of cognitive decline.
The Relationship Between Caffeine and Dementia
This new report was authored by researchers in France who completed a cross-sectional study using data from 263 people who had either mild cognitive impairment or Alzheimer’s disease between 2010 and 2015.
The participants completed a survey on their habitual caffeine intake, which asked how much coffee, tea, chocolate, and soda they had daily. They also underwent “clinical, neuropsychological, and biological assessments” when they enrolled in the study.
Those who were able underwent magnetic resonance imaging (MRI) brain scans, and the participants also provided samples of their blood and their cerebrospinal fluid.1 Cerebrospinal fluid is found in the hollow spaces of the brain and spinal cord and between the layers of tissue that protect them.
The participants were divided into two categories depending on their median caffeine consumption:
- Those with a median caffeine consumption equal to or less than 216 milligrams a day were put in the “low caffeine consumption” group.
- Those with a median caffeine consumption higher than 216 milligrams a day were put in the “high caffeine consumption” group.
For reference, 12 fluid ounces of caffeinated soda contains between 23 and 83 milligrams of caffeine. One cup of coffee contains 113 to 247 milligrams of caffeine, while a 12-ounce energy drink can have between 41 and 246 milligrams of caffeine.
After adjusting for factors such as age, sex, smoking status, and more, the researchers found that people who drank less caffeine had a higher risk of being amnestic. This means that they experienced issues with memory loss in particular, as opposed to other non-amnestic cognitive impairments, where someone might have trouble making sound decisions or judging how to complete a task.
The researchers also found an interesting link between caffeine consumption and levels of a protein called amyloid in participants’ cerebrospinal fluid samples. Specifically, people who drank less caffeine had lower levels of plasma amyloid-β 42 (Aβ42) and abnormal ratios of other types of amyloid proteins. Lower levels of Aβ42 in the cerebrospinal fluid are associated with Alzheimer’s disease.
Amyloid proteins can clump together in the brain to form plaques, which researchers believe could lead to issues with brain function.
Right now, it’s not clear why caffeine could influence the risk of Alzheimer’s and dementia, though experts do have theories.
“Caffeine may block the formation of beta-amyloid from amyloid precursor protein,” Irina Skylar-Scott, MD, clinical assistant professor of neurology and neurological sciences at Stanford Health Care, told Health. “Caffeine may also improve amyloid clearance from the brain. However, these are still hypotheses for the mechanism behind how caffeine may affect amyloid protein, and they haven’t been proven.”
It’s also important to note that the study simply found an association between higher caffeine consumption and lower incidence of memory loss—caffeine may not be the cause.
“Cross-sectional studies like this one can’t establish causality, so they are a starting point for further research,” Skylar-Scott said. Randomized control trials on the association between caffeine consumption and Alzheimer’s and dementia may help researchers learn more, she added.
Can You Lower Your Risk of Alzheimer’s and Dementia?
Right now, it’s too soon to suggest that people should add extra caffeine to their routines as a way to prevent Alzheimer’s or dementia, experts said.
“As clinicians, we may recommend changes to caffeine consumption in the setting of anxiety or insomnia, but those recommendations are not based on dementia risk,” Skylar-Scott said.
The Food and Drug Administration advises against consuming more than 400 milligrams of caffeine a day—this is roughly two to three 12-ounce cups of coffee. Too much caffeine can lead to serious health problems, including high blood pressure, heart palpitations, increased heart rate, anxiety, digestive issues, dehydration, and sleep issues.
Unfortunately, outside of leading a healthy lifestyle, researchers don’t know a lot about how Alzheimer’s can be prevented.
“There isn’t a single food or ingredient that, through rigorous scientific research, has been shown to prevent, treat, or cure Alzheimer’s or other dementia,” Sexton said. “In fact, it is unlikely that one food or ingredient will have a significant beneficial effect against a disease as complex as Alzheimer’s.”
Instead, focus on maintaining a healthy lifestyle overall—that includes eating a healthy diet, staying physically active, and maintaining social connections to support brain health as you age.
“The takeaway message [from the new study],” Sexton said, “is that moderate caffeine consumption poses no risk to your cognition and overall health, as long as you have other good health habits.”
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