How often do you pick your nose? Your answer may determine your risk of Alzheimer's, warns new study

Woman holding her nose

Frequent nose-pickers are at an increased risk of Alzheimer's

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Adam Chapman

By Adam Chapman

Published: 09/02/2024

- 15:23

Updated: 09/02/2024

- 15:47

Researchers suggest the nose offers a "plausible route" for dementia-inducing germs to enter the body

A new study suggests frequent nose pickers are at an increased risk of Alzheimer's disease - the leading cause of dementia.

The finding adds to a growing body of literature that suggests lifestyle and environmental factors can influence the risk of brain decline.

For the study, published in the journal Biomolecules, researchers at Western Sydney University reviewed several published research papers and found that nose-picking introduces germs into the nasal cavity, or “olfactory system”.

They explained: “The olfactory system represents a plausible route for pathogen entry, given its direct anatomical connection to the brain and its involvement in the early stages of Alzheimer’s disease.”

Illustration of germ molecules entering a person's nose

The nose represents a 'plausible route' for pathogen entry, researchers say

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The researchers hypothesize that the invading germs trigger the brain to produce the amino acid beta-amyloid as a defence mechanism.

Beta-amyloid is a protein fragment strongly implicated in Alzheimer’s disease. It's thought to destroy synapses before clumping into plaques that lead to nerve cell death.

The researchers wrote: “Our review proposes the hypothesis that neuroinflammation in [Alzheimer’s disease] might be partially caused by pathogens entering the brain through the olfactory system.”

However, they do qualify that the jury is still out on whether the neuroinflammation comes after developing Alzheimer’s disease or before it.

They noted: “One of the limitations of the ‘infection hypothesis of [Alzheimer’s disease] is the debate of what comes first, the chicken (Alzheimer’s disease) or the egg (infection).

“Is it because subjects have a compromised immune system that they develop an infection leading to neuroinflammation and Alzheimer’s disease?

“Or does increasing inflammation due to ageing and sub-clinical Alzheimer’s disease cause immune defects or unhealthy habits allowing the entry of olfactory pathogens?”

Limitations aside, the study raises the promise of finding new and novel ways of preventing dementia.

It comes after a study published in Nature Scientific Reports suggested the bacterium Chlamydia pneumoniae enters the brain via the olfactory nerve from the nose leading to the development of amyloid beta plaques.

The authors of the 2022 study posited that nose-picking damages the nasal mucosa, making it easier for the bacteria to reach the olfactory nerve and enter the brain.

Dementia - how to spot it

Different types of dementia can affect people differently, and everyone will experience symptoms in their own way.

However, there are some common early symptoms that may appear some time before a diagnosis of dementia.

These include:
  • Memory loss
  • Difficulty concentrating
  • Finding it hard to carry out familiar daily tasks, such as getting confused over the correct change when shopping
  • Struggling to follow a conversation or find the right word
  • Being confused about time and place
  • Mood changes

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