There are usually two camps of people: those who reach for coffee as soon as their eyes are open, and those who eschew it completely.
If you’re in the former camp, new research suggests your morning brew may be doing more than giving you a kick start – it could also be linked to a lower risk of dementia later in life.
In a study led by researchers at the Harvard T.H. Chan School of Public Health and Mass General Brigham, it was discovered that drinking moderate amounts of caffeinated coffee or tea was associated with a reduced risk of developing dementia and slower cognitive decline over time.
An estimated 446,000 Australians are currently living with dementia, and that number is projected to grow significantly as our population ages.
Published in the Journal of the American Medical Association, the study followed more than 131,000 adults for up to 43 years, making it one of the most comprehensive investigations to date into the relationship between coffee, tea and brain health. Over the course of the study, 11,033 participants developed dementia.
Researchers found that people who drank two to three cups of caffeinated coffee a day had an 18 per cent lower risk of dementia compared to those who drank little or none. Similarly, those who consumed one to two cups of caffeinated tea daily also showed a lower risk of dementia and reported fewer signs of cognitive decline.
“When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention,” said 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. “Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”
Importantly, the protective link was seen with caffeinated beverages. Decaffeinated coffee did not show a statistically significant association with reduced dementia risk, suggesting caffeine itself may play a key role.
Why caffeine may support brain health
Coffee and tea contain a range of bioactive compounds, including caffeine and polyphenols, which are thought to have anti-inflammatory and antioxidant properties. Chronic inflammation and oxidative stress are both implicated in the development of dementia and Alzheimer’s disease, so compounds that counter these processes may help protect brain cells over time.
Caffeine may also improve insulin sensitivity and support cardiovascular health, both important factors, as conditions such as type 2 diabetes, high blood pressure and heart disease are known risk factors for cognitive decline.
That said, researchers are clear that this is an observational study. It shows an association between moderate caffeine intake and lower dementia risk, but it does not prove that coffee or tea directly prevents dementia. Other lifestyle factors – including diet, physical activity, education and social engagement – may also contribute.
The benefits observed in the study were modest, and more research is needed to understand the biological mechanisms at play. But given how widely consumed coffee and tea are, even small reductions in dementia risk at a population level could have a major impact.
It’s also worth noting that more is not necessarily better. The strongest associations were seen with moderate intake, around two to three cups of coffee per day. Excessive caffeine consumption can disrupt sleep and increase anxiety, both of which may negatively affect long-term brain health.
