I have been a regular coffee drinker since college (and especially during the challenging days of medical school.) Last year, I covered a pair of recent research papers indicating a link between regular coffee consumption and decreased mortality from strokes and cardiovascular disease.
A new research paper suggests a strong link between regular consumption of coffee (or tea) and decreased risk of developing dementia. A study of over 130,000 adult men and women between years 1980-2023 tracked dietary consumption of caffeinated coffee, decaffeinated coffee, and tea. This data was correlated with development of dementia as well as performance on neuropsychological tests.
The results were striking. After accounting for confounding factors, the people who drank caffeinated coffee had a significantly lower rate of developing dementia—specifically, 141 vs. 330 cases per 100,000 person-years. This is a greater than 50% decrease in the risk of developing dementia! The coffee drinkers also showed significantly improved objective cognitive performance on the neuropsychological tests.
If you prefer tea over coffee, don’t fret. According to the paper, “Higher intake of tea showed similar associations with these cognitive outcomes.”
However, the cognitive benefits only applied to those who drank caffeinated coffee. The authors noted that, “decaffeinated coffee intake was not associated with lower dementia risk or better cognitive performance.”
How much coffee should one drink? The paper states, “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.”
This amount is roughly in line with the earlier paper suggesting that for cardiovascular benefit, “the sweet spot for daily consumption can be found around 3 cups of coffee or tea (or 250 mg of caffeine)”.
The current paper on cognitive benefits of coffee did not distinguish between drinking coffee in the morning vs. drinking later in the day. (In contrast, one of the papers on the cardiac benefits found that coffee consumption was beneficial only in the morning, as opposed to drinking coffee throughout the day.) Nor is it clear if the effect is due to caffeine, one of the metabolites of caffeine, or some other bioactive substance within caffeinated coffee or tea that is absent in decaffeinated coffee.
As with similar prior reports, this is an observational study, not a randomized controlled trial. Correlation does not imply causation. There could be something subtly different in the behaviour or lifestyle of the regular coffee or tea drinkers vs. the non-drinkers that could affect one’s dementia risk independent of caffeine consumption. Ideally, further research can uncover any underlying biochemical mechanisms that could explain the association between caffeine intake and protection from dementia.
I would also love to see if this result holds up in populations in other parts of the world, where coffee consumption is common, but diet and lifestyle can vary widely from the US-based population sample in this study.
If you want to know about other health benefits of regular moderate coffee consumption, this article from Johns Hopkins Medicine covers a few more, including decreased risk of developing Parkinson’s disease, decreased risk of colon cancer, and improved liver health.
For now, I plan on maintaining my regular habit of drinking 1-2 cups of coffee a day without qualms. If you regularly enjoy some daily coffee, feel free to do the same!
