This Bad Habit May Increase Your Risk of Alzheimer’s Disease

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Cameron Whitman /

Your mother told you to never pick your nose — and that advice was probably wiser than even she knew.

People who pick their nose might introduce bacteria that travels up the olfactory nerve and into the brain, possibly increasing the risk of dementia and Alzheimer’s disease, according to a new study.

Researchers at Griffith University in Brisbane, Australia, monitored mice and found that Chlamydia pneumoniae traveled the nerve between the nasal cavity and the brain and then attacked the central nervous system. In response, brain cells deposited amyloid beta protein, which is considered a marker of Alzheimer’s disease. Scans of the brains of these mice showed patterns similar to what one would expect to find with dementia.

The olfactory nerve is a potent pathway for such bacteria because it has a short route to the brain and bypasses the blood-brain barrier.

In a summary of the researchers’ findings, James St John, head of the Clem Jones Centre for Neurobiology and Stem Cell Research and co-author of the study, said:

“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. We saw this happen in a mouse model, and the evidence is potentially scary for humans as well.”

It’s worth noting that the findings in mice don’t necessarily confirm that the same risk exists in humans. The researchers say the next phase of their study will focus on whether the same risk is present in people.

In the meantime, the researchers are sure of one thing: It’s a very bad idea to pick your nose or to pluck your nose hairs. According to St John:

“We don’t want to damage the inside of our nose and picking and plucking can do that. If you damage the lining of the nose, you can increase how many bacteria can go up into your brain.”

St John says the risk of developing dementia “goes right up” after the age of 65 and that bacteria and viruses might play a “critical” role in the course of the disease.

Multiple studies over the past couple of years have found evidence that infection with COVID-19 may increase the likelihood of developing dementia, and that it also may accelerate the timetable for being diagnosed with the disease.

St John adds that one of the first signs of possible Alzheimer’s disease is a loss of smell, and he recommends that people have their sense of smell tested beginning as early as age 60.

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