Episode 5: Making Sense of Smell

Bey
Hey, what’s up? Welcome to So Curious!, a new podcast from The Franklin Institute.

Angelica
In this season, Human 2.0, we will be talking to scientists and non-scientists about technology, innovation, and the human experience. We’re your hosts. I am Angelica Pasquini.

Bey
And I am the Bul Bey, but you could just call me Bey.

Bey
On today’s episode, we’re going to be talking about smell with Vice President of the Monell Chemical Senses Center, Nancy Rawson. Sight, taste, touch, smell…. Hearing?

Angelica
Oh, that’s the one. That was the one that we thought of last because we both love music so much.

Bey
And we both need people to hear us.

Angelica
Yeah, it’s true.

Bey
You know, that was the one thing, and I think I’ve told you this before. You’re a great listener. And someone being in comedy, I don’t know, I think my projected thought is that they’re looking for a space or a moment to show, to reveal, to tell. The prestige, I guess. Is that what that’s called? But you take in information and you just respond in a really sharp, concise way. What’s really cool is the science of creation and the science of connecting. And I think listening is a part of that. You listen to try to create in that moment, and you use the rest of the senses to do the same thing as well. And so trying to pull apart the senses, put them together and figure out how we use these things to navigate our spaces. It’s something that drives me for sure, especially music.

Angelica
Yeah. Do you ever hear sounds and then get inspired, or words, or something someone saidn that helps influence your lyrics?

Bey
Absolutely. And I’m really emo, so feelings like the touch and the feel of something really inspires me to try to how do I put something warm into sonics? How do I put something, I don’t know, smelly into an 808 drum? You know what I mean? All those different things. I love playing around with senses, for sure. And I definitely can’t wait to figure out how smell connects to a thought. How does taste connect to the smell? It’s interesting because we can kind of taste through our smell. Like you ever smell something that’s like you get it in your mouth?

Angelica
Yeah. Also, my sister can’t hear if she doesn’t have her glasses on. Okay?

Bey
Wow.

Angelica
It’s so dramatic. But she can’t pay attention if she doesn’t have her glasses on. She’s like, wait, I have to get my glasses. I can’t hear you. Okay. But you know what? It’s real and it’s true. It also makes me think of synesthesia like Jimi Hendrix had? And I think they say Andre 3000 has it, from Outkast. But is it Andre 2000?

Bey
It’s 3000.

Angelica
It’s three. Yeah. He can taste, color and smell sound. Also, apparently Kanye. But you know what? I want to experience that. If that were like an exhibit, I would be so into going.

Bey
That would be crazy. That’d be great. And I know one thing, too, that I’ve heard for years and have experience is when you’re parallel parking, you have to turn the music down. You have to do it quietly because you can’t concentrate. So there has to be something about loud noise, distraction, that plays around with your sight or focus for sure. There has to be something there.

Angelica
I need silence. I like silence. I think my food tastes better if it’s quiet.

Bey
Wow.

Angelica
You ever eat in a quiet room as opposed to… Well, I grew up Italian. Big household. Everyone was constantly talking. Now I’m obsessed with silence when eating.

Bey
I love that.

Angelica
Okay, let’s just get right into it by talking to an expert today about smell.

Bey
Our next guest is Nancy Rawson. Nancy Rawson is the Vice President, Associate Director, and Associate Member at the Monell Chemical Senses Center. Her research uses cell-based tools to understand and develop the function of chemosensory receptor cells. This understanding can then be used to treat and prevent various health challenges related to metabolism, aging, and neurological disorders. The Monell Center is the only independent scientific nonprofit dedicated to research on taste and smell.

Angelica
Hey, Nancy, welcome to the show. Can you please introduce yourself?

Nancy Rawson
I’m the Vice President of the Monell Chemical Senses Center in Philadelphia. We’ve been here for over 50 years studying taste, smell, and nutrition. And my background ranges from science to business to dance.

Bey
Cool. Well, thank you for being here. We’re really excited and curious, of course, to talk to you. I wanted to go to…”olfactory.”

Angelica
Go ahead.

Bey
I learned, like, a couple of seconds ago what that actually meant. And could you just explain it for the general audience? I thought it was a noun.

Nancy Rawson
So we have three chemical senses. These are chemicals that our bodies detect in the environment and help us respond appropriately to make sure we survive, and find mates, and avoid danger. So one of these is our sense of smell. And our sense of smell is biologically-based on a system called the olfactory system. We use the word “olfactory” as an adjective or “olfaction” is the noun.

Bey
And, you know, I’m from Philadelphia, born and raised and all that jazz. When I see, like, “Ol” at the start of a word, I think it’s like some “ye olde” language situation from Old City or something.

Nancy Rawson
Well, actually, it’s funny you said that because the olfactory system is the oldest sensory system in our bodies, evolutionarily speaking.

Bey
Wonderful.

Nancy Rawson
It’s a system that evolved before anything else. The very first primitive little organisms swimming around in the soup had to be able to detect chemicals in their environment.

Angelica
Yeah, I do think we smell things before we see them in life.

Nancy Rawson
Absolutely. Yeah.

Angelica
We were talking about smell before you came in. And how it helps us orient the entire world that we are existing in. I first just wanted to ask, how does a person, sort of, find their way to this specific part of science? What you drew to it?

Nancy Rawson
So I had a little circuitous path. I was very interested in nutrition and food intake and healthy diets and so forth. And I got a master’s degree in nutrition. And then I went to work at Campbell Soup Company, and I was in the nutrition department. We were trying to lower the salt in the soup, as everybody wants to do.

Bey
Yeah.

Nancy Rawson
And I got very interested in why do people like salt so much, and what does it do to the flavor of soup, and why is it so good, and asking all these “why” questions? And so I started to take courses at the University of Pennsylvania and eventually got my PhD in biology. The area I ended up doing my research in was more related to energy metabolism and appetite control. But I did some work at the Monell Chemical Senses Center as part of my research. And I got to know some of the work they were doing there. And when I went to continue my postdoc, I worked with someone who was studying olfaction, and he was using some really advanced techniques at the time for studying live cells through a microscope to see how they reacted to different stimuli. And these happen to be human olfactory neurons. So the actual nerve cells that detect odors.

Bey
Right.

Nancy Rawson
My initial intent was to learn these techniques, go back and study energy metabolism. But I got so entranced by the sense of smell that I ended up spending the next 17 years studying smell, and evenually taste.

Angelica
I mean, where’s the documentary? Let’s get it. We need the rights to the movie! I’m obsessed with it!

Bey
Angelica, I was going to say, what’s so interesting about this So Curious! podcast is with each person and expert that comes in and talks about what they studied. I always am intimidated. Like, this is going to be such an incredible story, you know, they really wanted to dissect the world. And it’s like, no, I wanted to know why soup was so salty, and why people liked it so much. And I’m like, that’s a really simple inquiry. And so, I don’t know, it makes it common for everybody. Just ask a question and follow that question and then see where that leads you in the world of science. I think that’s incredible.

Angelica
They say that the salt is the compliments in the food, but it is not good for you.

Nancy Rawson
Too much is not good for you.

Bey
Right, moderation!

Angelica
Too much is not good for you. Yeah, for real.

Bey
So I’m going to ask a silly question and then get to some more serious ones. Earlier, you mentioned our sense of smell, helping with identifying mates. I’ve heard and seen some stories in the past of people enjoying….for lack of language…a stinky person.

Bey
And that being something that was a draw. Are you saying that that’s not so much of a weird thing? That actually falls into a place of reasonability?

Nancy Rawson
Absolutely. So our sense of smell is much better than most people give it credit for. For a long time, people were considered as not having a very good sense of smell because we use our vision so much, and our hearing. And it’s certainly true that consciously that’s what we think about more. But through many, many years of research and studying all kinds of animal systems, we’ve learned that really humans are in many ways as good as and in some ways better than many animals with our sense of smell. And it’s just not always conscious. It’s not a conscious recognition. So there has been research showing that people can certainly recognize others of their family. Mothers can recognize the smell of their infants.

Angelica
Yeah. People definitely dig each other’s smells. I mean, sometimes you like someone and you just don’t know why. And there’s this whole thing going on.

Nancy Rawson
And one of the ways that we’ve learned the importance of this is when people lose their sense of smell. And one of the things that we hear over and over again is, “I really miss the smell of my mate, or the smell of my child, not being able to smell my child.” And that really brings it home. How important this sense is that you just don’t recognize it until you don’t have it.

Angelica
Yeah. So now with the onset of COVID, we have smell loss. And the research being done is making strides in the science world to restore smell loss. This is part of what you work on, right?

Nancy Rawson
That’s right.

Angelica
All right. So can you speak to this work? And what has been the process since COVID began?

Nancy Rawson
COVID has really changed the world of what we call chemosensory research, the research world into smell. There’s been a huge coming together of scientists from all around the world who are now collecting data and integrating that information globally in a way that has never been done before. And it’s really shown us how much progress we can make when that can happen. It’s also really accelerated our work to be able to do better assessment of our sense of smell. One of the big challenges that we were hit with immediately was, we had these anecdotal reports of people losing their sense of smell, but we didn’t have really good, valid, quick, inexpensive ways of measuring that sensory loss. And so we had to rely on self-report. And people aren’t very good at self-assessing their sense of smell.

Angelica
Oh, yeah.

Nancy Rawson
So that’s another aspect. And Monell has developed a rapid test called Sentinel that is “lift and sniff.” It runs, you know, you put your phone up to the UPC code. It pops up some questions, you lift up these film strips and sniff each one and answer some questions. And that was funded by the National Institutes of Health to develop this test. And now we have a manufacturing partner. And what our goal is, is that when you go to your doctor, maybe when you go to your dentist, you’ll have a smell test, the same way you have regular eye tests or hearing tests that we’ll have smell testing.

Angelica
Yeah.

Bey
Right.

Angelica
I have to ask what it smells like. Is it a flower? Is it strawberry?

Nancy Rawson
So there’s three different… Well, there’s a variety of odors that we put, and three strips. And so one of them has an odor. Two of them have no odor. So part of the test is, which one has the odor? So, if you can smell or not. Part of the test is how intense is that odor on a scale that you just move the slider. And then part is identification. So you’re given four choices. And so you have to pick which of these four choices does it smell like? It might be popcorn, it might be floral, it might be minty, it might be bubblegum. So there’s a variety of odors.

Angelica
You need to know what you’re smelling. Yeah. And be able to identify it.

Bey
100%. And something that stood out to us on the website is a section that’s called “Digitizing Taste and Smell.” Is what you just spoke about, does that fall under “Digitizing Taste and Smell?”

Nancy Rawson
So the concept with Digitizing Taste and Smell really goes beyond that, to the concept that you wrote of, “our smartphones become smell-phones.”

Bey
I love it.

Angelica
Right.

Bey
No. Make a note.

Angelica
Okay. Copyright note.

Nancy Rawson
You heard it here first!

Angelica
Yes, it’s you, all Nancy, “smell-phone.” Love it. Okay. Yeah, so… Digitizing Taste and Smell.

Nancy Rawson
Yeah. So our vision there is ultimately that a mother will be able to enjoy the smell of her baby from wherever she is. And a doctor may be able to use some type of a device to detect, check your aroma from your breath, or from your blood, or your other systems, and transmit that information electronically to another site where they can analyze it and say, oh, we better change your medication, or we better do something.

Angelica
And so the phone itself that you’re holding it will be able to do that? That’s the technology of the future?

Nancy Rawson
I think that there will be devices like that. Yes. It’s sort of reminiscent of the Star Trek tricorder kind of a concept.

Angelica
Wow.

Nancy Rawson
So right now, we already have devices that are quite portable that can detect and analyze thousands and thousands and thousands of chemical compounds very quickly. They’re very expensive today, of course. Right. So that technology has to advance. Then the technology for — and this is actually the harder part — for converting that information into information that relates it to the smell perception. So that’s the hard part. So if you think about a television set, the color on the television set, we have a code for describing every color that we can see, a mathematical code. We can describe it precisely. And if I use that code to describe a color, anybody, anywhere in the world can replicate that color, and it will be accurate. We do not have that code for smell today. And so that’s where the research is going on, to try to understand that code, which really means understanding how the brain does this task.

Bey
Yeah, that’s fascinating.

Angelica
Smell is so emotional. I would love to hear your thoughts on what the heck is going on when you smell something. And then there’s this whole wave of emotion that flows through your body.

Bey
Right, right!

Nancy Rawson
Right. So from a simple anatomy perspective, these nerve cells that connect to the olfactory bulb, the next connection is the part of the brain responsible for memory and emotion. And so that’s part of the reason. And the other part of the reason is that these senses — especially smell, because it is the distance one, right, you get that first — is so important for your survival. If you were a primitive animal and you couldn’t smell the predator coming, you did not survive in the gene pool, right?

Angelica
Totally.

Nancy Rawson
It needs to have that very rapid, very tight connection with appropriate emotional responses, whether positive or negative.

Angelica
Okay. This was fascinating to us. Dogs sniffing out cancer? So this is something that …Can you speak about this projec,t and what it says about the future of smell research? What are the possibilities? And also, what is the dog smelling? What the heck is going on?

Nancy Rawson
Yeah, that’s a really good question. So it’s been known for a long time. And actually human doctors did this when my dad was young. The doctor would come into the room and he would smell the patient and use that for diagnosis.

Angelica
Amazing.

New doctors don’t do that. But dogs, dogs can be very sensitive, but what they are really good at is discrimination. So dogs have a lot more of these odor receptors types than we do. And they’re also very good at creating air flow turbulence that makes them very acutely sensitive to very tiny differences in odor characteristics. So dogs are really good at discriminating when there’s differences. And this was first noticed in epileptic patients who had dogs that would be able to alert them when they were about to have a seizure, or sometimes in diabetics, that were going into ketosis, because their body odor changes. And so everything…your metabolism gives off all kinds of chemicals. And these chemicals come out in the skin, in your sweat, in your breath. And any shift in that metabolic state, whether it’s a little bit of inflammation or whether it’s an infection or whether it’s in the case of diabetes, for instance, changes in blood sugar, that changes the types of chemicals that are released.

Nancy Rawson
And one of the things that we’re thinking now is that a lot of what the dog is actually smelling isn’t necessarily that chemical, but the result of your skin or your oral microbiome acting on those chemicals.

Nancy Rawson
Because it’s these bacteria, our microbiome, that are giving off these volatile chemicals all the time. These small, really tiny little molecules that are what the dogs are picking up on. So a lot of the research is going into now, better understanding, how the microbiome is influencing the chemicals that are being produced through our metabolic processes and our disease processes.

Angelica
Absolutely.

Nancy Rawson
Again, one of the end goals for this type of work is to develop these devices that will smell you, that will collect that smell information and transmit it in a way that the machine-learning large databases [with] historical information about all of the different chemical odor signatures that might be associated with different aromas, different diseases, can be analyzed and then used to generate diagnostic information.

Angelica
How do the senses affect our nutrition? You’re passionate about nutrition as well, right?

Nancy Rawson
Yes.

Angelica
So our smell often has to do with what we’re eating, obviously, right? And then that’s coming out of our body. So what are your thoughts on nutrition as far as ….Obviously it’s helping our health, but how does it relate to the work that you’re doing?

Nancy Rawson
So one of our research themes we’re calling “sensory nutrition.”

Angelica
Okay.

Nancy Rawson
Which is really kind of a new term for work that has been going on for a long time, where we are applying sensory science to better understand our nutritional health and improve our nutritional health. So flavor, what we think of as flavor, is a mixture of odor, taste, chemical irritation, texture. All of these senses go into what we think of as flavor. And really it’s the flavor of foods –we eat what we like, at the end of the day.

Angelica
Yes, yes we do!

Nancy Rawson
I worked as a nutritionist, I can tell you! You can tell people, “you should eat this or you should eat that.” People will eat what they like!

Angelica
Yeah.

Nancy Rawson
So from a diet control perspective, flavor perception is very important. And from a health perspective, the sensory aspects of food contribute to how we metabolize our food. So even before you’ve eaten anything, just as you’re smelling the food and putting it in, at the beginning, [when you] first put it in your mouth before you’ve actually swallowed, that triggers neural processes that tell your stomach, “food is on its way, so get ready!” And triggers the release of different types of enzymes that are going to be digesting the food. So our sensory experience of food does contribute important ways to our metabolism and our digestion of food and making sure that the body can use that food efficiently.

Bey
Are we able to alter our personal taste to control our diets?

Nancy Rawson
So, taste can shift.

Bey
Okay.

Nancy Rawson
It was shown a number of years ago by Gary Beacham from Monell that, if you put people on a low salt diet for a period of time, their preferred level of salt does decrease. So you actually can shift their preference. What we don’t know for sure yet is if the preference shift was due to changes at the level of the tongue, like did they become more sensitive to salt? There’s some evidence for that. But it’s not completely known. Or, whether it’s completely going on centrally, in the central nervous system.

Angelica
Right.

Nancy Rawson
And probably both.

Angelica
Yeah.

Nancy Rawson
Because these systems do tune themselves to their environment. We know for both smell and taste that if you are exposed… An example in smell, there’s a chemical called androstenone, which is from boars. It’s, like, a sexual odor from boars, that some people can’t detect at all. Some people are really sensitive to it.

Angelica
Wow.

Nancy Rawson
Some people are in-between. If you’re not very sensitive to it, but you expose yourself to it over a period of time, you can become sensitized to it. So you actually start to make more of those receptors that can detect it.

Bey
It’s so fascinating. Are you able to share any, I guess, a banal story of someone losing their sense of smell and taste and what effect came from that?

Nancy Rawson
Right. So we’re learning through COVID in a big way that viruses are the major cause for smell loss. And when people do lose their sense of smell, as I mentioned before, it has dramatic effects on their emotional health because they report feeling isolated from people. And I think this comes back to what we were saying before about actually having some experience of other people’s odors, even though we’re not always conscious about it. It also can affect their food intake. So, I had one woman years ago who the only thing she could eat after she lost her sense of smell from a head injury were cinnabuns. Which, because of the cinnamon, is trigeminal, so that’s a chemical irritant. It works on a different system. And the fat, and the sugar, and the texture, right? But that’s hardly a healthy diet, right?

Angelica
Yeah. And that will have effects mentally, too, if that’s what you’re eating. I mean, it’s all connected.

Nancy Rawson
Exactly. We’re being faced with this global experiment in smell loss. A lot of the people do recover. They seem to recover. But then often when they go through this period of recovery, what they experience is something called parasmia. And this is almost worse in some ways than loss of smell, because what happens here is things don’t smell the way they’re supposed to. And unfortunately, they usually smell bad. So your cup of coffee might smell like smelly trash.

Bey
Right.

Angelica
How does that happen? Is it something that your brain knows the smell of? Something disgusting, and there’s like a crossed wire?

Nancy Rawson
It’s sort of like a crossed wire. But if you go back to that pattern recognition concept, or if you think about playing a chord on a piano and some keys are missing. Instead of hearing the chord that you should be hearing, you might be hearing something very different and dissonant.

Angelica
Dissonance, yeah.

Nancy Rawson
So as different parts of your nose recover at different rates, it’s likely that the receptors, the different receptors, are regenerating intermittently or in different rates. So not uniformly. So that’s messing up this code.

Bey
Right.

Nancy Rawson
And so the brain is doing the best it can with the information that it’s getting. One of the things that COVID has done, fortunately, is direct more funding towards research to help develop the tools that we need to really understand better how to help these systems regenerate.

Bey
Could you tell us about the future of regenerating loss of senses?

Nancy Rawson
As far as the future, Monell and other places have really developed some phenomenal tools to help us identify the specific growth factors and potential therapeutic treatments that will promote regeneration of these systems. The “ultimate” would be either a mixture of compounds that helps the system regenerate naturally, or potentially isolating the stem cells that you can then put back into the nose to create new mature olfactory neurons and sort of repopulate the system to start regenerating itself. And I do think that that technology is within reach. It’s certainly years away, but we have the ability to get there.

Bey
Right.

Nancy Rawson
And I think that what we can do today, really, obviously, other than staying as healthy as you can, wear your mask, not getting these viruses, because every time the system takes a hit like this, it increases the risk of your sense of smell not coming back.

Bey
Nancy Rawson, you are amazing. Thank you for coming and sharing your experience, your knowledge, your stories. This is really, really fascinating. Seriously. Thank you so much.

Nancy Rawson
Well, thank you. It’s been a pleasure.

Angelica
Okay. I’m processing. I’m downloading that information into my human brain. I think it’s time for us to talk about it.

Angelica
Okay. Well, that was amazing.

Bey
It was a breath of fresh air.

Angelica
Yeah.

Bey
I had to say, I’m sorry.

Angelica
I love when someone is really specialized in what they do, and it’s something I know nothing about that I can just learn. And there’s no one in my life who’s ever spoken to me about smell that way.

Bey
Right?

Angelica
I mean, wasn’t that nice?

Bey
What sticks with me is how deep of a connection you can have through smell like that could be the vehicle for you to lock in memory. That could be the vehicle for you to feel a very strong connection with someone and map out your environment. And I really appreciated being told that human beings have just as good a smell as dogs. We’re just different. I don’t want to use good, bad or better, but I really appreciated that.

Angelica
I loved when she also spoke about how people could smell diseases.

Bey
Right!

Angelica
That was really interesting,

Bey
Wasn’t it?

Angelica
The dogs sniffing cancer, but also even just the concept of people being able to smell when the body is about to do something different.

Bey
And it was a regular practice in the early 1900s or so, right? The doctor would walk in and sniff you.

Angelica
Yeah. You know what? I’m open to it.

Bey
Thanks so much to Nancy Rawson for sharing her experience. And thanks so much to you for tuning in to this episode of the So Curious! podcast.

Angelica
This podcast is part of The Franklin Institute. The Franklin Institute is a science museum located in Philadelphia. The Franklin Institute’s mission is to inspire a passion for learning about science and technology. For more information on everything about The Franklin Institute, visit fi.edu.

Angelica
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Angelica
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