Did you know that our ability to smell a range of scents, including leather and mint, could be linked to our dementia risk? In one study, participants who couldn’t correctly identify at least four of five aromas were about twice as likely to develop the condition as those who could.
We also know that Alzheimer’s disease might affect your sense of tasteand smell years before diagnosis. So strong is the link that losing your sense of smell is considered by some researchers to be about as much of a dementia risk factor as carrying the Alzheimer’s-related gene, APOE-e4.
Not only that, but some studies have suggested that bacteria which enter our nose, i.e., through nose-picking, could increase our likelihood of dementia (though this has been debated). Still, another paper involving mice found dementia-like changes in the rodents’ brains after nasal exposure to the respiratory tract pathogen chlamydia pneumoniae.
In case you think the nose-related connections end there, spoiler alert: they don’t.
A paper published in the Journal of Extracellular Vesicles. showed that a nasal spray which contained helpful bundles of genetic information made the “brain’s own repair systems switch on, healing inflammation and restoring itself”. It appeared to reverse some signs of brain ageing in just two weeks.
And scientists are trying to find out whether nasal swabs could one day help to detect early signs of Alzheimer’s, too.
So what’s going on here?
Why could the nose be relevant to dementia?
Speaking to HuffPost UK, Emma Taylor, the senior information officer at Alzheimer’s Research UK, said that the nose “probably” contains a uniquely vulnerable area point for the brain.
The neurons that detect smells are the only ones “directly exposed to the outside world,” a University of Auckland article notes.
So, Taylor told us, “Scientists are… investigating whether factors such as air pollution, inflammation and infections could affect brain health through the nose”.
However, while she says the idea that dementia might “start” in the brain is “intriguing”, the expert doesn’t think we have enough evidence yet to say that’s true.
After all, she explained, “Changes in a person’s sense of smell can happen years before symptoms of some diseases that cause dementia appear.
“Researchers are exploring whether this means the nose is simply an early warning sign, or whether it could be involved in some of the earliest stages of disease. For now, the evidence isn’t strong enough to say that dementia begins in the nose.”
Still, the area could “potentially” offer a point of intervention.
“Because of the close connection between the nose and the brain, researchers are exploring whether smell tests, nasal samples or medicines delivered through the nose could help diagnose or treat diseases that cause dementia,” Taylor ended.
“While these approaches show promise, more research is needed before they become part of routine care.”
In other words, the functionality of our nose seems linked to dementia, though working out the exact direction of that relationship is difficult. And while its unique structure could help scientists to both administer tools to relieve symptoms and spot the condition early, until we know more about how it works, nobody properly… you guessed it…
nose. (Sorry.)
