Given the research we do for this channel, I am no stranger to surprising, sometimes controversial—and occasionally disgusting—claims regarding Alzheimer’s disease.

In a previous video, we explored how something as mundane as earwax buildup—or, more technically, cerumen impaction—could lead to hearing loss and, by extension, cognitive decline.

Today, we’re looking at a physical habit.

It’s often dismissed as a minor social faux pas—and was even the subject of jokes in an old Seinfeld episode. But recent research suggests this common behavior might create a pathway for certain pathogens to reach the brain.

We’re talking about nose-picking—and its potential link to late-onset dementia.

For the companion video, see here:

The Griffith University Study

A team of researchers at Griffith University in Australia published a 2022 study in the journal Scientific Reports. They focused on a bacterium called Chlamydia pneumoniae.

This common airborne bacterium—sometimes called the Taiwan Acute Respiratory Agent—is primarily known for causing bronchitis and pneumonia. However, it has also been detected in a significant number of human brains affected by late-onset dementia.

Using mouse models, the researchers tracked how this bacterium travels. What they found was striking: it can move along the olfactory nerve—from the nasal cavity directly into the brain.

In these models, infection reached the central nervous system within 24 to 72 hours. Once inside, it triggered amyloid-beta deposition—the same protein associated with Alzheimer’s plaques.

One interpretation is that amyloid-beta may function as part of the brain’s immune response to infection. However, if that infection becomes chronic or repeatedly facilitated—potentially through damage to the nasal lining—this process could contribute to neurodegeneration.

In short: this research suggests that certain behaviors might make it easier for pathogens to access the brain.

Connection: The Earwax Analogy

You may remember from our earwax discussion that conductive hearing loss involves a physical obstruction—something like earwax blocking sound transmission.

In a similar way, the nasal epithelium acts as both a physical and immunological barrier.

The Griffith University study found that when this barrier was damaged, infections in the mice became significantly more severe.

Think of the nasal lining as a security checkpoint: if it’s intact, most threats are stopped. If it’s compromised, things can slip through.

Just as we cautioned against inserting objects into the ear canal, scientists now warn that picking—or plucking nose hairs—can damage this delicate lining. That damage may give pathogens a clearer route to the brain.

Why This Matters

As geriatrician Maria Carney noted in our earwax discussion, “most people don’t even realize that they have an issue.”

That lack of awareness is a recurring theme in both Alzheimer’s prevention and detection.

While nose-picking is often associated with children, it remains common in adults. In fact, one study found that about 91% of people admit to it.

I’m curious how that compares with this audience—so I’ve put up an anonymous poll if you’d like to weigh in.

As many viewers know, age alone—especially over 65—significantly increases Alzheimer’s risk.

If we add environmental exposures, such as introducing pathogens through repeated nasal damage, this could represent an additional, potentially modifiable risk factor.

Caveats and Disclaimers

To be clear: this is early-stage research conducted in mice. We do not yet have direct evidence that this pathway operates the same way in humans.

Human trials would be needed to confirm whether a similar mechanism is at work.

And of course, Alzheimer’s disease likely involves multiple contributing factors—including acetylcholine loss, plaque formation through other mechanisms, neurofibrillary tangles, and nutritional or metabolic influences.

So yes—this hypothesis may sound farfetched.

But it is being seriously explored, and it may be worth paying attention to.

Practical Advice and Conclusion

One of the core goals of the Alzheimer’s Proof project is prevention. And unfortunately, there is no single solution—no magic bullet.

What we can do is try to stack the odds in our favor.

Protect the Barrier

Avoid plucking nose hairs and minimize behaviors that could damage the nasal lining. Chronic irritation may increase vulnerability.

Use Safer Alternatives

If needed, consider electric trimmers for grooming. For congestion, saline sprays or nasal irrigation may help. If using a neti pot, always use distilled or properly purified water.

Keep It Clean

If you must manually clear your nose, ensure your hands are clean—before and after. Also keep fingernails trimmed and smooth to reduce the risk of micro-injury.

Stay Aware

Consult a healthcare provider if you experience persistent irritation, bleeding, or signs of infection.

The key takeaway here isn’t panic—it’s awareness.

Small habits, repeated over time, can shape long-term brain health.

And if reducing Alzheimer’s risk comes down—even in part—to eliminating preventable factors, then even small changes may be worth considering.

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References:

• David Nield, “Nose-Picking May Have a Surprise Link With Alzheimer’s, Study in Mice Suggests,” Science Alert, April 5, 2026, <https://www.sciencealert.com/nose-picking-may-have-a-surprise-link-with-alzheimers-study-in-mice-suggests>. 
  
• Anu Chacko, Ali Delbaz, Heidi Walkden, Souptik Basu, Charles W. Armitage, Tanja Eindorf, Logan K. Trim, Edith Miller, Nicholas P. West, James A. St John, Kenneth W. Beagley, and Jenny A. K. Ekberg, “Chlamydia pneumoniae can infect the central nervous system via the olfactory and trigeminal nerves and contributes to Alzheimer’s disease risk,” Scientific Reports, vol. 12, no. 2759, February 17, 2022, <https://www.nature.com/articles/s41598-022-06749-9>. 

• “Can Earwax Buildup Cause Memory Loss? Cerumen Impaction & Dementia,” video, Alzheimer’s Proof (YouTube), Oct 24, 2020, <https://www.youtube.com/watch?v=OVnZJuM__mc>.