A study published in 2022 found a tenuous but plausible link between picking your nose and an increased risk of developing dementia.
In cases where picking at your nose causes internal tissue damage, critical species of bacteria have a clearer path to the brain, which responds to their presence in ways that resemble signs of Alzheimer’s disease.
There are numerous caveats here, not the least of which is that the supporting research so far is in mice rather than humans, but the findings are definitely worth further investigation – and could improve our understanding of how Alzheimer’s disease starts, which remains somthing of a mystery.
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A team of researchers led by scientists from Griffith University in Australia ran tests with a bacterium called Chlamydia pneumoniae,which can infect humans and cause pneumonia.
C. pneumoniae has also been discovered in the majority of human brains affected by late-onset dementia.
The video below has a summary of the study’s findings:
It was demonstrated that in mice, the bacteria could travel up the olfactory nerve (joining the nasal cavity and the brain).
What’s more, when there was damage to the nasal epithelium (the thin tissue along the roof of the nasal cavity), nerve infections got worse.
this led to the mouse brains depositing more of the amyloid-beta protein – a protein that is released in response to infections.
Plaques (or clumps) of this protein are also found in significant concentrations in people with Alzheimer’s disease.
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“We’re the first to show that Chlamydia pneumoniae can go directly up the nose and into the brain where it can set off pathologies that look like Alzheimer’s disease,” said neuroscientist James St John from Griffith University in Australia, when the study was published in October 2022.
“We saw this happen in a mouse model, and the evidence is perhaps scary for humans as well.”
Could Nose Picking Be Linked to Alzheimer’s Disease? New Research Explores the Connection
Table of Contents
Recent research suggests a surprising potential link between a common habit – nose picking – and an increased risk of developing Alzheimer’s disease. While seemingly innocuous, this behavior may contribute to the progression of the neurodegenerative disease by introducing bacteria into the brain. Scientists are now investigating whether this connection is causal and if it’s a reversible process.
The Bacteria-Amyloid Beta Link
The research, initially published in Scientific Reports in 2022 and revisited in subsequent reviews like one in 2024, centers around Chlamydia pneumoniae, a common bacterium found in the nasal passages. This bacterium has been implicated in Alzheimer’s disease for some time,and the new hypothesis suggests nose picking could be a key pathway for its entry into the brain.
According to Griffith University researcher Dr. John St John, the team’s work focuses on how environmental factors, specifically bacteria and viruses, contribute to the progress of Alzheimer’s. “[W]e think that bacteria and viruses are critical,” he stated in a Griffith University news release.
The theory proposes that when individuals pick their noses, they can introduce C. pneumoniae and other microbes into the olfactory epithelium, the tissue lining the nasal cavity responsible for smell. From there, the bacteria can travel directly to the brain via the olfactory nerve.
Once in the brain, the bacteria can trigger an immune response, leading to the formation of amyloid plaques – a hallmark of Alzheimer’s disease. Amyloid-beta protein deposits are a key characteristic of the disease, and researchers are now investigating whether their increase is a natural immune response to infection that could be reversed once the infection is cleared.
Alzheimer’s Disease: A Complex Puzzle
Alzheimer’s disease is a complex condition with multiple contributing factors. While age is a significant risk factor – risk increases substantially after age 65 – it’s not the sole determinant. The National Institute on Aging highlights the role of genetic,lifestyle,and environmental factors in the disease’s development.
The current research doesn’t suggest nose picking causes alzheimer’s, but rather that it might very well be a contributing factor, especially in individuals already predisposed to the disease. The team is working to understand the full extent of this potential link.
Further Research and Considerations
Researchers are continuing to investigate the relationship between C. pneumoniae, nose picking, and Alzheimer’s disease. A key question is whether the amyloid-beta protein deposits are a protective immune response or a damaging process.
It’s importent to note that this research is ongoing, and more studies are needed to confirm these findings and determine the extent to which nose picking contributes to Alzheimer’s risk.However, it highlights the importance of considering environmental factors and potential pathways for infection in the development of this devastating disease.
Sources:
* St John, J. (2022, October 28). new research suggests nose picking could increase risk for Alzheimer’s and dementia. Griffith University.https://news.griffith.edu.au/2022/10/28/new-research-suggests-nose-picking-could-increase-risk-for-alzheimers-and-dementia/
* ScienceAlert. (2025,January 24).Scientists think nose picking could be linked to Alzheimer’s disease. https://www.sciencealert.com/scientists-think-nose-picking-could-be-linked-to-alzheimer-s-disease
* National Institute on Aging. (n.d.). Alzheimer’s and dementia. https://www.nia.nih.gov/health/alzheimers-and-dementia
* Begemann, M., et al. (2022). *Plausible pathogenic