Mouse study suggests nose picking has surprising link to Alzheimer’s

A study published in 2022 found a weak but plausible link between picking your nose and an increased risk of developing dementia.

While picking your nose can damage internal tissues, important species of bacteria have a clear path to the brain, which responds to their presence in ways similar to Alzheimer’s disease symptoms.

There are several caveats here, not the least of which is that the supporting research so far has been in mice rather than humans, but the findings are certainly worth further investigation — and may improve our understanding of how Alzheimer’s disease begins, which remains a mystery.

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A team of researchers led by scientists from Australia’s Griffith University tested the bacteria. Chlamydia pneumoniawhich can infect humans and cause pneumonia.

C. Pneumonia It has also been detected in the majority of human brains affected by late-onset dementia.

The video below summarizes the study’s findings:

It was demonstrated that in mice, bacteria can travel up the olfactory nerve (connecting the nasal cavity and brain).

What’s more, when the nasal epithelium (the thin tissue lining the nasal cavity) is damaged, the nerve infection worsens.

This caused the mouse brains to accumulate more amyloid-beta protein – a protein that is released in response to infection.

Plaques (or clumps) of this protein are also found in significant concentrations in people with Alzheimer’s disease.

“We are the first to show this Chlamydia pneumonia can go directly to the nose and brain where it can set off pathologies similar to Alzheimer’s disease,” said James St. John, a neuroscientist at Griffith University in Australia, when the study was published in October 2022.

“We’ve seen this happen in a mouse model, and the evidence is potentially alarming for humans as well.”

Scientists are surprised by the speed C. Pneumonia Once absorbed into the central nervous system of mice, infection occurs within 24 to 72 hours. It is thought that bacteria and viruses see the nose as a quick route to the brain.

Although it is not certain whether the effects will be the same in humans, or whether amyloid-beta plaques are also the cause of Alzheimer’s, it is important to follow promising leads in the fight to understand this common neurodegenerative condition.

“We need to study this in humans and confirm whether the same pathway works the same way,” St. John said.

“This is research that has been proposed by many people, but has not yet been completed. What we do know is that these same bacteria are in humans, but we haven’t worked out how they get there.”

Related: Nasal spray may reduce Alzheimer’s disease, study in mice suggests

Picking the nose is actually not a rare thing. In fact, it’s likely that 9 out of 10 people do it… not to mention a bunch of other species (some a little more proficient than others).

While the benefits are unclear, studies like these should give us pause before making a choice.

Future studies on similar procedures in humans are planned — but until then, St. John and his colleagues suggest that picking your nose and plucking your nose hair is “not a good idea” because of the potential damage to nasal tissue.

“We don’t want to damage the inside of our nose and picking and plucking can do that,” warns St. John.

“If you damage the lining of the nose, you can increase how much bacteria can get into your brain.”

A great question the team is trying to answer is whether increased amyloid-beta protein deposits are a natural, healthy immune response that can be reversed when fighting infection.

A 2024 review further advanced the hypothesis that nose picking may play a role in increasing the risk of developing Alzheimer’s disease—revealing more about how the process may unfold.

RELATED: Alzheimer’s Causes May Come From Inside Your Mouth

It’s clear that Alzheimer’s is an incredibly complex disease, with so many studies on it and so many different angles scientists are taking to understand it—but each piece of research brings us a little closer to finding a way to stop it.

“Once you get to 65, your risk factor goes up, but we’re looking at other factors, because it’s not just age — it’s also environmental risk,” St. John said.

“And we think bacteria and viruses are critical.”

The research was published in 2015 Scientific reports.

An earlier version of this article was published in November 2022.

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