Research
Coffee, Tea, and Dementia – Promising Signals but Far from a Miracle Cure
Article no. 27 · May 19, 2026 · Updated September 20, 2026 ·
For a long time, coffee and tea have primarily been discussed in terms of sleep, heart rate, and daily habits. But in recent years, research has begun to ask a different question: can what we drink also affect the aging of the brain? A new large study published in JAMA in early 2026 has attracted attention. The results have since been highlighted by several media outlets. The picture emerging is cautiously hopeful.
A very large study – and an unexpectedly clear pattern
Researchers analyzed data from large American long-term studies where participants were followed for many years. Participants regularly reported their coffee and tea drinking habits while researchers monitored the development of dementia and cognitive function.
The results indicated that individuals with higher consumption of caffeinated coffee had a lower risk of developing dementia compared to those with low consumption. Tea also showed a similar correlation.
In the data, the most beneficial results were observed at approximately:
- 2–3 cups of coffee per day
- 1–2 cups of tea per day
Decaffeinated coffee, however, did not show the same clear link.
Why might coffee affect the brain?
Researchers point to several possible mechanisms.
Caffeine affects brain signaling, but coffee and tea also contain many other biologically active substances – particularly polyphenols.
The hypotheses are that these substances can:
- reduce low-grade inflammation
- reduce oxidative stress
- improve blood vessel function