I was sitting in a conference in August, drifting as I so often do between listening to what was on stage and pretending to be doing important work on my laptop (by which I mean sending memes on WhatsApp). All of a sudden, from the stage, the renowned biologist Aviv Regev came out with a sentence that made every single person in the room sit up and pay attention: “Of course,” she said, “we now know that Alzheimer’s starts in the nose.” I’m sorry, what? I didn’t know Alzheimer’s starts in the nose.
My own lovely dad died from Alzheimer’s last year, and ever since his diagnosis, I’ve done an incredible amount of digging into the disease, trying to understand what was happening to him. I was astonished I’d never come across this idea. And perhaps you haven’t either.
Which is why I want to share my astonishment at discovering that Aviv Regev was right – not only is Alzheimer’s closely associated with our sense of smell, but there is a growing body of research suggesting that our noses might have something to do with why the disease develops in the first place. The first bit you might already know: people with Alzheimer’s tend to lose their sense of smell, sometimes years before any symptoms of memory loss start to show up. But it turns out that our ability to smell is a surprisingly good indicator of our overall health (looking at you, covid-19).
One study from 2014 found that smell loss in older people was a better predictor of whether they would be dead within five years than a cancer diagnosis. Could pollution find its way to the brain via smell receptors? It’s not that losing your sense of smell itself will kill you.
More that the olfactory nerves are deeply intertwined with some of the most important memory structures in the brain, so when they start to deteriorate, it can be an early warning that something much more serious is going on. And this connection seems to work in both directions. One intriguing study (admittedly with quite a small sample size) put a diffuser with essential oils by older people’s beds, thus exposing them to all kinds of wonderful scents while they slept.
After six months, the people who had the olfactory enrichment performed better on memory tests than those in a control group. But not what Regev had been suggesting. Her words seemed to imply that noses are actually responsible for the trouble in the first place.
Extract — continue reading at the source.
