Coffee is more than a morning ritual at the breakfast; it connects us with ourselves and others, encouraging focus and pleasure. But can drinking this caffeinated drink help prevent or slow the progression of dementia? New research suggests it might.
Bruce McMichael
29 April 2026
Moderate coffee drinkers (around 3 cups per day) tend to have a lower risk of dementia, according to new research published by a group of US-based universities. However, the effect is described as a correlation rather than proof of cause and effect, and several limitations inform these findings.
Dementia is an umbrella term for a set of symptoms (cognitive decline, a gradual, noticeable loss of thinking abilities, such as memory, reasoning, attention, and language) caused by various diseases. Alzheimer’s is a specific degenerative brain disease and the most common cause of dementia.
The research was published in JAMA (The Journal of the American Medical Association) and led by investigators from Mass General Brigham, Harvard T.H. Chan School of Public Health, and the Broad Institute of MIT and Harvard. It analysed existing data from two US-based cohorts, the Nurses’ Health Study (started in 1976 and focussed on 121,700 female nurses aged 33-35) and Health Professionals Follow-Up Study (51,529 male health professionals aged 40-75). The researchers notes that potential biases and data collection limitations remain.
Such studies have limitations and detractors. 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’. Gounder added that, while the research found only a small reduction in risk, the data showed an association, not proof of causation. She cautioned that factors other than caffeinated beverages might have contributed to the observed association, according to CBS.
The report published in JAMA also noted that, ‘the most pronounced associated differences were observed with intake of approximately 2 to 3 cups per day of caffeinated coffee or 1 to 2 cups per day of tea’.
The analysis of 43 years of investigation found that moderate consumption of caffeinated coffee and tea was associated with a lower risk of dementia and modestly better cognitive function. Despite the study’s length, the limitations of observational research prevent firm conclusions about causality.
Speaking to The Harvard Gazette, senior author Daniel Wang, associate scientist with the Channing Division of Network Medicine in the Mass General Brigham Department of Medicine and assistant professor at Harvard Medical School, said “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. Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”
Although several studies have associated coffee consumption with a reduced risk of dementia, it should not be seen as a guaranteed preventive measure. The probable benefits appear to stem from how coffee’s compounds interact with the brain over time.
The new report’s lead author, Yu Zhang, a student at Harvard Chan School and a research trainee at Mass General Brigham, said: “We also compared people with different genetic tendencies 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”.
There’s also evidence that it may reduce the buildup of proteins associated with Alzheimer’s disease.
Coffee is a major source of antioxidants (such as polyphenols) linked in the fight against oxidative stress, something closely linked to dementia and cognitive decline. Oxidative stress is when harmful molecules build up in your body and start damaging your cells because your natural defences can’t keep up. Such oxidative stress has been linked to dementia and cognitive decline.
Coffee is also known to increase levels of neurotransmitters, for example, dopamine and serotonin, both of which are well known for boosting mood and physical health.
Luxembourg-based Alzheimer Europe, a membership organisation for national associations, notes that ‘caffeine has also been reported to improve the sensitivity to insulin and vascular function, both of which may help protect the brain against cognitive decline’.
Another link between coffee and dementia revolves around chronic inflammation in the brain, which is also a major factor in dementia. Coffee contains compounds that may reduce inflammation of the brain’s nervous tissue.
However, in common with all foods and drink, too much caffeine can alter sleep patterns and indeed poor sleep increases dementia risk, with benefits also dependent on genetics and overall lifestyle.
Coffee consumption alone will not prevent dementia. Good protection can be achieved through a combination of regular exercise, a healthy diet (such as Mediterranean-style foods), regular sleep, and staying mentally and socially active, each of which is associated with improved brain function.
Continuing with the research, a 2021 study by the UK Biobank said that participants “who were followed up over a period of 10-14 years. In total 365,682 participants, aged between 50 and 74, took part in the research,” reported the UK-based charity Alzheimer’s Research UK. The UK Biobank is the world’s largest and most comprehensive dataset of biological, health and lifestyle information made available for scientific studies.
Participants self-reported their tea and coffee drinking habits at the beginning of the study. Researchers then recorded the number of people who went on to have a stroke (2.8%) or develop Alzheimer’s disease or vascular dementia (1.4%).
Commenting on the Biobank research, Alzheimer’s UK reported that people who drank two to three cups of coffee or two to three cups of tea per day had around 30% lower risk of stroke and dementia when compared to those who didn’t consume either. This association was found among people who drank either tea or coffee, as well as among those who drank both.
Dr Rosa Sancho, Head of Research at Alzheimer’s Research UK, speaking on alzheimersresearchuk.org, noted that, “For most of us, our risk of dementia depends on the complex interaction of our age, genetics and lifestyle. We know that stroke increases the risk of developing vascular dementia. Understanding which aspects of our lifestyle have the greatest impact on our brain health is key to helping people make well-informed decisions about their lives.”
Studies like this struggle to pinpoint cause and effect, said Sancho. While the researchers attempted to control for other factors that could affect a person’s risk of stroke and vascular dementia, no firm conclusions can be made about whether tea or coffee causes this lower risk. Limitations in study design mean results should be interpreted with caution.
Participants only reported tea and coffee consumption at the beginning of the study, and there is no data on long-term habits, so it’s not clear how relevant the findings are to long-term brain health. This limitation makes it difficult to draw strong conclusions about ongoing consumption effects.
Ultimately, as the collective evidence suggests, there is no single silver bullet that will either prevent or heal Alzheimer’s. So, while medical research continues, it is probably best to exercise regularly, eat fresh, healthy food, and keep in touch with friends and family.
