Drinking two to three cups of coffee each day may lower your risk of dementia by as much as 35%, according to a massive new long-term study. The protective effect was strongest in adults younger than 75, and benefits plateaued beyond moderate intake.
The Research
Researchers analyzed data from 131,821 nurses and healthcare professionals followed for up to 43 years, starting when participants were in their early 40s. Over the study period, 11,033 participants (about 8%) developed dementia. Those who regularly consumed moderate amounts of caffeinated coffee or tea had a significantly lower risk. For adults aged 75 and under, consuming about 250-300 mg of caffeine daily — equivalent to two to three cups of coffee — was linked to a 35% lower dementia risk.
The study, published in The Conversation on May 13, 2026, also found that people who drank more than that did not gain extra protection. Interestingly, decaffeinated coffee drinkers experienced faster memory decline, likely because many switched to decaf after developing conditions like high blood pressure or sleep issues that are themselves linked to cognitive decline.
Potential biological mechanisms include caffeine’s ability to block adenosine, a chemical that slows brain messengers like dopamine and acetylcholine. Caffeine may also reduce inflammation, regulate blood sugar metabolism, and lower levels of amyloid plaques — toxic proteins associated with Alzheimer’s disease. Coffee and tea also contain other protective compounds like antioxidants and substances that support healthy blood vessels.
Why It Matters
This study provides some of the strongest evidence yet that a simple daily habit — drinking moderate amounts of caffeinated coffee or tea — could meaningfully reduce dementia risk. Since dementia affects millions worldwide and currently has no cure, lifestyle factors are crucial. The findings suggest that two to three cups of coffee is the “sweet spot” for brain protection, while more may not help and could even harm due to increased anxiety or poor sleep.
What You Can Do
- Aim for 2-3 cups of caffeinated coffee or 1-2 cups of tea daily.
- Don’t exceed 300 mg of caffeine (roughly three 8-oz cups of coffee).
- Be aware that decaf may not offer the same benefits; if you have health conditions, talk to your doctor.
- Combine with other brain-healthy habits like exercise, social engagement, and a balanced diet.
Source: ScienceDaily Mind & Brain
Curious about your own brain? Take our free adaptive IQ test or try 306 brain training levels.
