A recent JAMA study, summarized in Psychiatric News, adds to growing evidence that caffeine consumption may be associated with a lower risk of Alzheimer’s disease and cognitive decline: https://psychiatryonline.org/doi/full/10.1176/appi.pn.2026.05.5.6
However, caffeine can also have negative effects, and experts caution against starting a coffee or tea habit solely to improve cognition.
The key point is not that coffee or tea “prevents” dementia, but that moderate caffeine intake may be one helpful lifestyle factor for brain health.
- Primary argument: People who regularly drink caffeinated coffee or tea may have better cognitive aging outcomes than people who drink little or none.
- Study design: Researchers followed 131,821 adults from two long-term U.S. health studies, the Nurses’ Health Study and Health Professionals Follow-Up Study, for up to 43 years.
- Main finding: During follow-up, 11,033 participants developed dementia. Higher caffeinated coffee intake was linked with lower dementia risk.
- Size of effect: People in the highest caffeinated coffee group had an 18% lower dementia risk compared with those in the lowest group. They also reported less subjective cognitive decline, 7.8% versus 9.5%.
- Tea also helped: Higher tea intake showed similar favorable associations with dementia risk and cognitive outcomes.
- Decaf did not show the same benefit: Decaffeinated coffee was not significantly linked with lower dementia risk or better cognitive performance. This suggests caffeine may be part of the protective effect.
- Best amount: The strongest association was seen with about 2 to 3 cups of caffeinated coffee per day or 1 to 2 cups of tea per day.
- Simple interpretation: Moderate caffeinated coffee or tea may support brain health, possibly through caffeine and polyphenols that reduce inflammation and cellular damage.
- Important limitation: This was an observational study. It shows a relationship, but it does not prove that coffee or tea directly prevents dementia.
- Practical takeaway: Caffeinated coffee or tea may be one small part of a healthy aging plan, along with sleep, exercise, nutrition, cardiovascular health, and regular medical care.
