New research suggests that moderate caffeine consumption may offer benefits for both brain health and heart rhythm, potentially reducing the risk of dementia and certain types of irregular heartbeat.
A pair of recent studies, published in JAMA Network, indicate a link between higher intake of coffee, tea, and caffeine and a lower risk of developing dementia. Researchers also found a possible connection between caffeine and a reduced risk of atrial fibrillation, the most common type of heart arrhythmia.
The studies revealed that individuals who regularly consume caffeine and caffeinated beverages showed a lower prevalence of subjective cognitive decline and even slight improvements in cognitive function. According to researchers, “even after adjusting for risk factors related to Alzheimer’s and dementia, caffeine consumption was associated with a reduced risk of developing dementia, as well as a reduction in the risk of cognitive decline.”
Professor Anne-Julie Tessier, a specialist in nutrition and health longevity at the University of Montreal’s nutrition department, commented on the findings. “The strongest associations were observed at moderate consumption levels—around two or three cups of coffee or tea per day—and no additional benefit was seen with higher intakes.”
Researchers suggest this is “biologically plausible,” explaining that the body has physiological limits on how it absorbs, transports, metabolizes, and stores caffeine and other bioactive compounds found in coffee and tea. They also caution that excessive caffeine intake can disrupt sleep or increase anxiety, potentially negating any neuroprotective effects.
The observed associations remained consistent regardless of genetic predisposition or other major risk factors for dementia and cognitive decline, the study authors noted.
The research suggests caffeine may reduce pro-inflammatory cytokines in the brain and lessen neuroinflammation, both key factors in cognitive decline and the development of Alzheimer’s disease. Beyond caffeine itself, coffee and tea “contain bioactive compounds…that offer antioxidant and vascular benefits by reducing oxidative stress and improving cerebrovascular function.”
“Chlorogenic acid, the main polyphenol in coffee, could be protective for the brain,” Professor Tessier explained. “There’s also trigonelline, which is involved in glucose metabolism. We shouldn’t forget about certain minerals found in coffee either. The hypothesis here is that all these compounds could reduce inflammation and stress in the brain. We also believe that regular consumption helps the brain clear toxic proteins responsible for diseases like Alzheimer’s.”
The study also points to caffeine’s ability to improve insulin sensitivity and reduce the risk of type 2 diabetes—a major risk factor for dementia—as contributing to its protective effect on cognitive health. Certain components of tea may offer additional benefits by promoting relaxation and neuroprotection.
“We’re seeing a potential benefit, and we’re also seeing that it’s safe,” said Tessier. “But the key message here is really to stay in moderation.”
Atrial Fibrillation
Atrial fibrillation is the most common form of heart arrhythmia. Surprisingly, a study last fall found that drinking just one cup of coffee per day may reduce the risk of an episode by 39% in patients with the condition, compared to those who avoid caffeinated beverages.
During the six-month study period, 47% of participants who drank one cup of coffee daily reported episodes of atrial fibrillation lasting more than 30 seconds, compared to 64% of patients in the no-caffeine group.
“A tolerance develops when you drink coffee,” Professor Tessier said. “And there are certain benefits found in coffee—bioactive compounds with antioxidant properties that could play a role and have some benefits for heart health.”
Researchers noted that all study participants were regular caffeine consumers. They suggest further research is needed to examine the impact of caffeine on patients with atrial fibrillation who consume little to none.
Because participants limited their intake to one cup per day, the researchers caution that their findings may not apply to patients who consume more or who drink energy drinks containing caffeine.
In light of these results, the authors suggest “it is reasonable for healthcare professionals to allow their patients with atrial fibrillation to consider consuming naturally caffeinated substances they enjoy, such as tea and coffee.”
However, they also emphasize that “some people may still find that caffeine…triggers or worsens their atrial fibrillation.”
