On Memories (3/5): Why smell matters more than you think | Paule Joseph

0:02This is TED Health, a podcast from the TED Audio Collective, and I'm your host Dr. Shoshana Ungerleider. Here's a question you probably haven't thought about lately. How's your sense of smell? If that sounds like a strange thing to bring up in a conversation about health, get ready to rethink that. In today's episode, chemosensory scientist, nurse researcher, and TED Fellow, Polly Joseph, explores how smell isn't just about flowers or freshly baked cookies. It's a critical and often overlooked part of our well-being. From early clues about dementia to the lingering effects of COVID, your nose might be trying to tell you something important.

0:42And here's the kicker. Most of us, even our doctors, aren't listening. In this special podcast version of her TED Fellow film, Polly offers a surprising and actionable reminder to pay closer attention to the signals that our senses send us. Because when it comes to health, what we can't smell can hurt us.

1:08And now, TED Fellow Polly Joseph. I love the smell of rain. Just the amazing smell when you go outside. It takes me back home to Venezuela. I love the smell of chlorine in the summertime. My kids love swimming, but I love just really spending time with them in the pool. The smell of, like, crayon. It really takes me back to, like, kindergarten. The smell of Christmas. Because it's my birthday. But I love the smell of Christmas. I just think like apple crust, cinnamon, pine trees, those combinations. I hate the smell of Thanksgiving. The smell of fresh baked bread always reminds me of my mom and makes me smile.

1:47The smell can actually transport us into so many different dimensions. And I just love, love the idea that it does that. I am a chemosensory scientist and nurse researcher, and I study how diseases affect the senses of taste and smell. Our sense of smell is the only sense that is directly linked to our brain's limbic system, which controls memory and emotions. It can make us happy, it can make us sad, feel more calm and regulate our emotions or regulate our feelings. But if you ask most people what of the five senses they will give up, the most common answer is smell. Many people don't realize that smell is very important in the sense that it tells us whether something is going well or not, whether something is spoiled or whether you have gas leaking in your kitchen.

2:33One of the things that ignited my curiosity about smell was the times that I was working as a nurse and smelling infection, smelling poop, smelling decay. And that taught me that smell was really a primal sense that we really ignore at our own peril. I'm interested in how diseases impact smell. We know that our sense of smell tends to decrease as we age, but our sense of smell also decreases when different conditions like neurodegenerative diseases. So for example, Alzheimer's, Parkinson's disease, or frontal temporal lobe dementia. So it's one of the first symptoms that actually declines at least 10 years prior to any other symptoms appear.

3:12Yet the lack of clinical attention to smell means that we don't yet consistently use standardized tools to screen, diagnose, or identify these changes. So my mother-in-law is an incredible chef. However, a few years back, we noticed that all the food coming out of her kitchen was extremely salty. For me, I knew that something was wrong. So one of the things that I did was test her sense of smell. And it was immediately obvious that it was diminished. So she had hypostmia or decreased sense of smell. That then led us to take her to the doctor, and they were able to look at all her other symptoms.

3:44And we were able to then have a diagnosis that she had frontotemporal of dementia. Even when she was having symptoms, none of her clinicians tested her sense of smell. If we were able to test the sense of smell early on, it can provide us at least some early information. So at least it will tell us that something is wrong. During COVID, we know that millions of people started losing their sense of taste and smell. For a lot of diseases that are viral, people will lose their sense of smell. And that somewhat is normal. You get a cold, you lose your sense of smell. However, when COVID, this was a sustained loss of smell that was happening at the magnitude that it was occurring.

4:25So that really started to tell us that something was wrong. We know that people tend to lose their sense of smell and regain it. But the question is, to what degree? For many chemosensory scientists or smell researchers like myself, we're really concerned about the connection that we know that already exists between the sense of smell and our brains. and the possibility that many individuals that have lost their sense of smell with COVID will now have an increased risk of having neurodegenerative diseases. Since we don't test the sense of smell, we don't know individuals' baselines to really know what is happening over time.

5:01We haven't prioritized this research and testing, although we have tools that we use for research, but really standardized tools across medical offices are not there. Ideally, we can have individuals measured every year, Smell testing available from childhood all the way to adulthood. Just like when you go and get a physical exam, you can have actually your sense of smell measured. We know that our sense of vision is directly linked to how we experience the world. However, when it comes to the sense of smell, that's never tested. And one of the reasons is because we really don't appreciate it or really prioritize it.

5:38We just really think that, oh, it's just there to smell flowers. but smell can really help us. Imagine if we had smell tests that everyone could get, which would provide early information on diseases and give us insight into our overall well-being. We can actually tap into that power and use it for our own benefit.

6:11That was TED Fellow Polly Joseph. And that's it for today's episode. Thank you so much for listening. TED Health is a part of the TED Audio Collective, and I'd love to hear your thoughts about this episode. Send me a message on Instagram at ShoshanaMD. This episode was produced by me, Shoshana Ungerleiter, and Jess Shane. Edited by Alejandra Salazar and fact-checked by Vanessa Garcia-Woodworth. Special thanks to Maria Lages, Farrah Degrunge, Daniela Balarezo, Constanza Gallardo, Tansika Sangmarniwang, and Roxanne Heilash.