Friday, January 3, 2020

Smelling Sickness

The Annual Report from the Monell Center is out, and I'd like to copy a few interesting bits over the coming weeks.

The Monell Center in Philadelphia specializes in taste and smell research, and their first piece of news is about volatile signals for disease. We know that illnesses makes us smell different. Body odor comes from our distinct metabolic byproducts, and when our metabolism is disrupted, by a disease for example, it smells different. Dogs know this, and so does Alexandra Horowitz who wrote the book Being a Dog: Following the Dog Into a World of Smell (2016).

We can smell it too. Bruce Kimball, PhD, sensory neuroscientist Johan Lundstrom, PhD, and collaborators at the Karolinska Institute in Sweden reported that people can detect acute inflammation in others just by the smell of their urine.

But what we didn't know it actually changes the way others smell, just by being around us. Chemical ecologists Bruce Kimball, PhD, and Stephanie Gervasi, PhD, partnered with behavioral biologist Gary Beauchamp, PhD, to show that body odors of otherwise healthy people can change in an environment shared by sick-smelling people (or animals, according to the experiment).

Don't forget that the olfactory system is such a primitive part of us. It doesn't just go back to our animal ancestors, but even further. Plants don't see, and they don't hear.* But they can smell. Not the way we would consider smell, but they can sense chemicals in their environment, and those chemosignals can instigate immune response all by themselves. When a nearby plant is attacked by bugs, for example, they emit an olfactory alert to that their neighbors detect, and then beef-up their own chemical defense systems (by emitting bug-repellant vapors).

If you think about it, we're doing the same thing, only it's not us, it's the primitive chemosensory part of us. It detects potential threats in our environment, via the olfactory alerts from others, and rearranges our immune system accordingly.

Good to know, thanks Monell.

*Although you could say that plants "see" because they have some kind of photoreceptor that can tell where the light is and how much is there, etc.

Monell Center, Philadelphia PA

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