Coffee consumption and dementia

Will drinking coffee prevent Alzheimer's?

Coffee prevents dementia. No wait — coffee is bad for you. Actually, green tea is what you need. Or is it? Health headlines can’t seem to agree on coffee.

I love coffee and generally tend to dismiss health headlines… but I did come across a genetics study that may explain some of the disparate headlines. Moreover, the statistical benefits for coffee consumption for specific genotypes are fairly significant — actually larger than what studies show for exercise.¹

First, let’s take a look at some of the general population studies. The population-level data is interesting, but stick with me — the genetics study may help you figure out if these findings actually apply to you.

Should you drink coffee for your brain?

Keep in mind that coffee contains both caffeine and polyphenols. So the question arises - if coffee is beneficial, is it the caffeine or is it a specific polyphenol? Tea also contains caffeine as well as some different polyphenols. Another question is whether caffeine or coffee is neuroprotective in general, or only for Alzheimer’s disease.

Here are some of the studies on coffee and dementia from the past few years.

• A July 2025 study showed that drinking 3+ cups of coffee cut the risk of Alzheimer’s by over 40% and may also protect against Lewy body dementia.

• An analysis of multiple studies on caffeine shows that it is neuroprotective against dementia, and the animal studies also show caffeine to be neuroprotective in Alzheimer’s models.²

• A meta-analysis combining data for 750,000+ participants found that the risk of dementia decreased linearly with tea intake (more tea = less dementia). For coffee, there was a decreased risk of dementia when drinking 1 - 3 cups per day.³

• A smaller study in 587 individuals over age 90 showed that consuming 200+ mg of caffeine per day was associated with a 34% lower risk of dementia compared with consuming less than 50 mg/day.⁴

• Another study with 2500 older adults also found that caffeine consumption (266 mg - 495 mg/day) decreased the risk of dementia by around 40%. However, decaffeinated coffee had no statistical effect on dementia in this study.⁵

These give a nice average look at the population as a whole, and they point to caffeine specifically having a benefit in preventing dementia. However, everyone is unique — these studies may not apply to you.

Let’s get more personal and look at genetics:

Caffeine is metabolized by the CYP1A2 enzyme (primarily). There are genetic variants in the CYP1A2 gene that impact how the enzyme functions — leaving some of us as fast caffeine metabolizers, and some as slow or intermediate metabolizers.

This is why some people can drink coffee in the afternoon and others need to cut off caffeine early in the day to avoid sleep disturbances at night.

A French study of about 6,000 older adults (avg. age 74) looked at coffee consumption and dementia rates over a median of 9 years. Here’s where it gets interesting: the protective effect wasn’t the same for everyone.

The researchers found that when dividing the group by fast or slow/intermediate metabolizers of caffeine, it was only the individuals with slow or intermediate CYP1A2 enzyme function (slow or intermediate caffeine metabolism) who had a decreased relative risk of dementia. While one cup of coffee decreased the risk by 10%, more seemed to be better - with 4 cups of coffee decreasing the risk of dementia by ~40%.⁶

Why would slow CYP1A2 function interact with dementia?

Caffeine reduces alkaline phosphatase levels, and it also stimulates nitric oxide synthase in the endothelial cells lining blood vessels.⁷ ⁸ Caffeine also enhances heat shock protein response.⁹ Heat shock proteins are like chaperones that help protect against protein misfolding.

Thus, it may be that a longer exposure time with caffeine remaining in the system for longer is beneficial. Or, it may be a combination effect here, with caffeine providing some of the benefit, and slower CYP1A2 function being somehow slightly beneficial on its own.

One question that came to mind: did the French study take into account smoking and the interaction with CYP1A2? This matters because cigarette smoking is still fairly common in France (about a third of people smoke), and the polyaromatic hydrocarbons (PAHs) in cigarette smoke significantly upregulate CYP1A2 expression. This means someone with fast CYP1A2 who also smokes may metabolize caffeine extremely quickly. Perhaps non-smokers with faster CYP1A2 function still get some benefit from coffee

If you want to check your own CYP1A2 genetic variants, you can easily do so on Genetic Lifehacks or by looking at rs762551 if you have genetic data. The C/C and A/C genotypes are slow and intermediate for caffeine metabolism. The A/A genotype is the fast caffeine metabolizer.

If you’re thinking — I can’t drink caffeine because it makes me jittery… Well, that is also likely to have a genetic component due to an adenosine receptor (ADORA2A) genetic variant.

My takeaways:

As an intermediate caffeine metabolizer, my 2 - 3 cups of coffee habit could be a good thing. I do cut myself off by noon, since caffeine later in the day tends to reduce my sleep quality. This was something that I didn’t really notice until I used a sleep tracker, but it was obvious from the data that while I could fall asleep just fine, caffeine later in the day decreased deep sleep and made it more likely that I would be wide awake at 3:30 am.

Coffee consideration for APOE4 carriers:
Another new Alzheimer’s study looked at the effects of nanoplastic particles (preprint, in animals). The researchers found that the APOE4 animals had noticeable changes in memory and behavior with microplastics and nanoplastics added to their drinking water. They also had neuroinflammation and microglia activation. However, the APOE3 model animals didn’t show effects from the plastics in their drinking water.¹⁰

To tie these together: For someone with slow or intermediate CYP1A2 function along with APOE E4, coffee may help protect against Alzheimer’s, but it is important to avoid microplastics and nanoplastics in your hot drinks.

Look at how you’re making your coffee — and if you’re getting coffee while out and about, bring a travel mug along to avoid microplastics from the to-go cups.¹¹ I’ve found that most places are more than fine with me bringing my own cup. For home brewing, a ceramic pour-over set or a plastic-free French press may be the way to go. Or just go all out and get a good espresso machine. It’s for your health:-)

My splurge this year was to get a high-quality burr grinder. I went with a hand grinder so that I don’t wake up the household while grinding coffee in the morning. There’s just something very satisfying about hand-grinding coffee with a good grinder.

1. Iso-Markku, Paula, et al. “Physical Activity as a Protective Factor for Dementia and Alzheimer’s Disease: Systematic Review, Meta-Analysis and Quality Assessment of Cohort and Case-Control Studies.” British Journal of Sports Medicine, vol. 56, no. 12, Jun. 2022, pp. 701–09. PubMed, https://doi.org/10.1136/bjsports-2021-104981.

2. M Yelanchezian, Y. Mukish, et al. “Neuroprotective Effect of Caffeine in Alzheimer’s Disease.” Molecules (Basel, Switzerland), vol. 27, no. 12, Jun. 2022, p. 3737. PubMed, https://doi.org/10.3390/molecules27123737.

3. Li, Fengjuan, 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 & Function, vol. 15, no. 16, Aug. 2024, pp. 8330–44. PubMed, https://doi.org/10.1039/d4fo01750a.

4. Paganini-Hill, Annlia, et al. “Lifestyle Factors and Dementia in the Oldest-Old: The 90+ Study.” Alzheimer Disease and Associated Disorders, vol. 30, no. 1, 2016, pp. 21–26. PubMed Central, https://doi.org/10.1097/WAD.0000000000000087.

5. Dong, Xue, et al. “Association of Coffee, Decaffeinated Coffee and Caffeine Intake from Coffee with Cognitive Performance in Older Adults: National Health and Nutrition Examination Survey (NHANES) 2011–2014.” Nutrients, vol. 12, no. 3, Mar. 2020, p. 840. PubMed Central, https://doi.org/10.3390/nu12030840.

6. Lefèvre-Arbogast, Sophie, et al. “Habitual Coffee Consumption and Risk of Dementia in Older Persons: Modulation by CYP1A2 Polymorphism.” European Journal of Epidemiology, vol. 39, no. 1, Jan. 2024, pp. 81–86. PubMed, https://doi.org/10.1007/s10654-023-01060-x.

7. Li, Jinrui, et al. “Exploring the Impact of Coffee Consumption and Caffeine Intake on Cognitive Performance in Older Adults: A Comprehensive Analysis Using NHANES Data and Gene Correlation Analysis.” Nutrition Journal, vol. 24, Jul. 2025, p. 102. PubMed Central, https://doi.org/10.1186/s12937-025-01173-x.

8. Echeverri, Darío, et al. “Caffeine’s Vascular Mechanisms of Action.” International Journal of Vascular Medicine, vol. 2010, 2010, p. 834060. PubMed Central, https://doi.org/10.1155/2010/834060.

9. Brunquell, Jessica, et al. “Coffee Extract and Caffeine Enhance the Heat Shock Response and Promote Proteostasis in an HSF-1-Dependent Manner in Caenorhabditis Elegans.” Cell Stress & Chaperones, vol. 23, no. 1, Jan. 2018, pp. 65–75. PubMed Central, https://doi.org/10.1007/s12192-017-0824-7.

10. https://www.biorxiv.org/content/10.1101/2025.05.02.651942v1.full

11. Chen, Huier, et al. “Release of Microplastics from Disposable Cups in Daily Use.” Science of The Total Environment, vol. 854, Jan. 2023, p. 158606. ScienceDirect, https://doi.org/10.1016/j.scitotenv.2022.158606.