A new review of studies supports the hypothesis that nose picking may contribute to an increased risk of developing Alzheimer’s disease.
It’s one of those ideas that seems absurd at first glance, but makes sense when you think about it. Simply put, bacteria and viruses on our fingers easily enter our bodies when we put them up our nose.
It must be taken into account that the olfactory system, located in the roof of the nasal cavity, has a direct route to the areas of the brain where Alzheimer’s wreaks havoc, like the hippocampus. This could be crucial when weighing up this risk, says the team responsible for the review at the University of Western Sydney (Australia).
“There are many factors that may contribute to the development of Alzheimer’s disease, such as amyloid peptide and tau deposits, but recent evidence suggests that neuroinflammation may also play – at least in part – a role in its pathogenesis,” write the researchers in their published article.
“In recent years, new research has examined the possible involvement of invading external pathogens in triggering or accelerating neuroinflammatory processes in Alzheimer’s disease.”
As explained in the article, nose picking – or rhinotillexomania, as it’s technically called – could indirectly lead to this brain inflammation, and there are several ways this could happen.
First, nose picking means that whatever we have at our fingertips (e.g. pathogens) is pushed toward the brain. Second, removing things from your nose affects the balance of your microbiome, which could cause it to be a less effective barrier for your body.
As the researchers point out, nose picking has previously been linked to an increased risk of infection: a study published last year showed a link between this habit and the possibility of contracting COVID-19, for example.
Nasal pathogens
Invading pathogens could cause the damage seen in Alzheimer’s disease. In 2022, another study linked nose picking to Alzheimer’s, in this case the research focused on mice. He showed that damage to the nasal epithelium (the tissue that lines the nasal cavity) can increase the risk of infection and trigger a response in the brain similar to that seen in Alzheimer’s patients.
Other telling indicators pointed out in the research include that some viruses have been regularly found in the brains of people with Alzheimer’s and that signs of Alzheimer’s are often first detected in the olfactory bulb, the part of the brain that detects smells.
We’re still a long way from a definitive conclusion that nose picking increases the risk of Alzheimer’s, but the signs are there, and as we better understand this complex disease, we can also work on more effective treatments.
“Understanding the potential role of olfactory pathogen invasion in AD-associated neuroinflammation opens new opportunities for prevention,” the researchers write. “Across all entry routes, improving hand hygiene could be a simple prevention step, as the COVID-19 epidemic has shown.”
REFERENCE
Neuroinflammation in Alzheimer’s disease: A possible role of nose picking in pathogen entry via the olfactory system?