At a Glance
- Moderate consumption of caffeinated coffee and tea is associated with a lower risk of dementia in large population studies
- The strongest protective patterns are consistently observed at moderate intake levels rather than heavy consumption
- Decaffeinated coffee has not shown the same cognitive association, suggesting caffeine plays a central role
- Excessively high caffeine intake may reduce potential benefits, particularly when sleep and cardiovascular factors are affected
Written By: Vennela Reddy, Bpharm
Reviewed By: Samruddhi Jadhav B.Sc-Microbiology,
MSc-Nutrition and Food Science
(Clinical & Holistic Nutritionist)
Daily coffee and tea habits have long sparked debate. Are these beverages protecting the brain, or quietly increasing long-term health risks? Recent large studies are offering reassuring clarity, and the message is encouraging for regular drinkers.
A landmark cohort analysis published in JAMA reported that higher intake of caffeinated coffee was associated with a significantly lower risk of dementia compared with low or non-drinkers. The strongest association was observed among individuals consuming roughly two to three cups per day, suggesting that moderate intake may offer the greatest benefit.
Importantly, the same protective association was not observed with decaffeinated coffee, a distinction that has drawn particular interest among researchers. This difference suggests that caffeine itself, rather than coffee as a beverage alone, may play a central biological role.
Beyond this large cohort analysis, similar patterns have been observed across multiple meta-analyses. Pooled research evaluating coffee, tea, and caffeine intake consistently reports modest reductions in dementia risk at moderate consumption levels, with benefits often plateauing rather than increasing indefinitely
Tea consumption has demonstrated a similarly favorable trend. Large population-based studies, including analyses derived from the UK Biobank, have reported lower dementia risk among regular tea drinkers. These studies frequently describe a non-linear relationship, where moderate intake appears more beneficial than either very low or very high consumption.
Researchers propose several biological explanations for these observations. Caffeine, a well-known neuroactive compound, influences brain signaling by blocking adenosine receptors. This mechanism not only contributes to alertness but may also affect pathways involved in neuroinflammation and amyloid-beta metabolism, processes linked to neurodegenerative disease progression.
In addition to caffeine’s effects, both coffee and tea contain antioxidants and polyphenols known to influence oxidative stress and vascular function. Since vascular health plays a critical role in maintaining cognitive performance, these compounds may contribute to the observed associations.
Despite these encouraging findings, experts emphasize an important limitation. Current evidence remains largely observational. While studies demonstrate consistent associations, they do not prove that coffee or tea consumption directly prevents dementia.
Another key theme emerging from research is the importance of dosage. More is not necessarily better. Several dose-response analyses suggest that protective associations are strongest at moderate intake levels, while excessively high caffeine consumption may reduce or negate potential benefits.
Very high intake may introduce unwanted physiological effects, including sleep disruption, heightened anxiety, and increased stress hormone activity. Because sleep quality is essential for memory consolidation and neural repair, chronic sleep disturbance may offset potential cognitive advantages.
Some studies have also explored intake patterns among individuals with underlying health conditions. Research focusing on hypertensive populations has suggested that associations between beverage intake and dementia risk may follow J-shaped or U-shaped curves, reinforcing the idea that balance is critical.
For patients and everyday readers, the practical message is reassuring. Moderate coffee and tea consumption does not appear harmful for long-term brain health. In fact, current research trends lean toward benefit rather than risk when intake remains within sensible ranges.
Coffee and tea are best viewed as supportive lifestyle factors rather than protective interventions. Brain health continues to depend primarily on well-established strategies, including physical activity, cardiovascular risk control, quality sleep, balanced nutrition, and cognitive engagement.
For millions of daily drinkers, the evolving science delivers welcome news:
Your morning cup is far more likely to be a friend to your brain than a foe.
Reference
Zhang Y, Liu Y, Li Y, et al. Coffee and Tea Intake, Dementia Risk, and Cognitive Function. JAMA. Published online February 09, 2026. https://jamanetwork.com/journals/jama/article-abstract/2844764
Ying Zhu et al, Moderate coffee or tea consumption decreased the risk of cognitive disorders: an updated dose–response meta-analysis, Nutrition Reviews, Volume 82, Issue 6, June 2024, Pages 738–748, https://doi.org/10.1093/nutrit/nuad089
Li F et al, Tea, coffee, and caffeine intake and risk of dementia and Alzheimer’s disease: a systematic review and meta-analysis of cohort studies. Food Funct. 2024 Aug 12;15(16):8330-8344. PMID: 39054894. https://doi.org/10.1039/d4fo01750a
Hu, HY et al. Tea consumption and risk of incident dementia: A prospective cohort study of 377 592 UK Biobank participants. Transl Psychiatry 12, 171 (2022). https://doi.org/10.1038/s41398-022-01923-z
Wang, B et al. Association between coffee and tea consumption and the risk of dementia in individuals with hypertension: a prospective cohort study. Sci Rep 14, 21063 (2024). https://doi.org/10.1038/s41598-024-71426-y
expert reaction to study looking at tea and coffee intake and dementia risk | Science Media Centre https://www.sciencemediacentre.org/expert-reaction-to-study-looking-at-tea-and-coffee-intake-and-dementia-risk/
Coffee Consumption and Risk of Dementia and Alzheimer’s Disease: A Dose-Response Meta-Analysis of Prospective Studies – PMC https://pmc.ncbi.nlm.nih.gov/articles/PMC6213481/