How to pronounce "substances"

In a recent survey,

a majority of respondents picked their sense of smell

as the one they'd be most willing to give up

among the traditional five senses.

But if you love food,

you should be giving your nose much more credit.

Because it’s actually our sense of smell

that plays a huge role in our ability to process flavor.

[Body Stuff with Dr. Jen Gunter]

First, let's talk about how smell works,

from coffee to stinky trash.

The substances around us give off volatiles,

which you can think of as tiny smell molecules.

We breathe in these smell molecules,

which then stimulate the olfactory sensory neurons

that sit high in the nose.

Each of these neurons contains an odor receptor on its surface.

Once the odor receptors are triggered by these smell molecules,

the neurons send information about them to the brain.

Here's what I think is so cool.

The brain not only categorizes that information as a particular odor,

it may also begin to associate feelings,

like pleasure or disgust and other moods and emotions with that odor

for future reference.

For example, you sniff bacon, you eat it,

your taste buds get salt,

and then your body gets a whack of fat,

which is an energy source.

So the brain loves it and attaches a positive label to it.

The next time you smell bacon,

a sensation associated with pleasure arises.

Now, there are a lot of smells out there,

more than our 400 or so odor receptors can detect.

But people with a healthy working sense of smell

have odor receptors that can combine

to detect anywhere between 10,000

to more than a trillion different odors.

Now, taste is completely different.

It comes from taste receptors on our tongues and in our mouths.

Taste is limited to the basics: salty, sweet, bitter, sour

and, somewhat controversially, umami or savory.

You can taste without smell,

but anyone with a stuffy nose can attest

that's a pretty bland experience.

That's because when we eat, for example, chewing pizza,

the pizza releases volatiles that travel from our mouths and throat

up through the nasal passage.

There, olfactory neurons get all the complex smells from the pizza

and send that information to the brain.

The smell and taste work together to help us enjoy food.

When our nose isn't working properly and food seems flavorless,

it's because we're only tasting those basic tastes

without any of the complex odors detected through smell.

So the next time you savor an amazing flavor,

thank your nose.

Our sense of smell is what brings nuance to what we eat.