It was the summer of 2020, and Sakeenah Benjamin tested positive for COVID 19.

I immediately lost my smell, my taste, all the symptoms that you heard early on about what people lose. I lost everything.

A month later, Sakeenah felt like she had recovered. She had regained her sense of smell and taste.

I started to feel like myself again or my old self, whatever that was. And moving forward, try to start living a normal life again. And all that changed on Halloween of 2020. So I was basically chilling on my couch in West Philly, and I think I was getting ready to watch Halloween.

I'm scared. There's nothing to be scared of. Are you sure? I killed him. You can't kill the boogeyman.

Get in there. Come on, Tommy! Now lock the door.

I was, like, sitting around in some candy and had some garlic parm truffle fries I, like, put in the air fryer to try to make them nice and crispy and just the best.

Sakeenah was cozy. She was feeling pretty good. And then suddenly something startled her. Something like out of a horror movie.

Everything tastes like rancid meat. And I thought I just bought a bag of old fries from the store. And something wrong with the wine possibly. Then I brushed my teeth and toothpaste tastes rancid as well. So it was like all of these things. I thought I had a terrible trip to the grocery store.

But nothing was wrong with Sakeenah's groceries. Instead, something in her body had changed.

It was like a switch flipped at my brain and nothing was normal. I would have like a bowl of oranges on my table, and I couldn't even eat those anymore because an orange wasn't an orange anymore. It looked like an orange. It probably smelled like an orange to any other person, but to me, it tasted like garbage.

Unlike earlier that summer, when she lost her smell and taste, this time around, Sakeenah was experiencing parosmia. That's a distorted sense of smell, another symptom of COVID 19. It sometimes appears after a patient's initial infection.

It was like, I don't want to say living in a world of darkness, but my brain just didn't know what was real versus what wasn't, I guess? It changed my life mentally and it changed my life physically.

Those who have experienced smell loss or smell distortion, like Sakeenah, say that it's hard to grasp just how important this sense is until it's gone. From smelling your favorite candle to tasting strawberry ice cream on a hot summer day, our olfactory system plays a crucial role in the way we experience life. So in today's episode, we're going to take a look at what causes smell, loss or smell distortion in COVID patients and how it could also be a sign of other diseases. Plus, we'll explore some of the ways doctors are treating this condition, including a technique called smell training. And for those of us who don't have smell challenges, there's something here for you, too, because we're going to hear how we can better appreciate and even strengthen this underrated sense. I'm Dr. Sanjay Gupta, CNN's chief medical correspondent. And it's time to start chasing life. As a doctor and someone who's reported on this pandemic from the start, I'm hopeful that today's episode will serve as a resource for the many people who have been recently affected by this issue. The reality is, because of COVID, more people are experiencing long lasting impacts to their senses. In fact, according to new data from the BMJ, a British medical journal, about 5% of COVID patients who initially lose smell or taste might go on to experienced long term dysfunction. If you do the math, that's 15 million people. Some people develop something called anosmia. That's loss of smell. Others develop parosmia or the distortion of smell, which is what Sakeenah experienced. We put out a call on social media asking for your experiences, and you all shared some pretty powerful stories.

Still, to this day, a year and a half later, I still can't eat red onions. Certain things tasted like rotting human flesh.

When I am using a sponge in the kitchen to clean and I smell it and I'm just like. Why does this smell like this? It smells like rotten cheese.

Still no taste or smell. Consequence of that is I had a kitchen fire because I could not smell. By the time I realized what it was, the flames were almost two feet high.

I lost 15 pounds in and around a week and a half just from not eating. And then since then, I haven't been able to gain the weight back. Eating pasta, which is my favorite food, just felt like eating mushy nothingness.

I think probably a lot of your listeners, if they had to choose one sense that they had to lose. If you thought about your sight or your hearing, all of these things seem so important. People often would say, "Oh yeah, I'd give up my smell." But you really don't know until it's gone, until you've lost it. Or like me, you work with people all the time who have lost it, how truly impactful that is to people's quality of life and the way in which we relate to each other.

That's Dr. Zara Patel. She's a rhinologist, basically a nose expert. She's also a professor at Stanford University. She's been researching treatments for disorders related to the ears, nose and throat for over a decade now. But she says in the past, patients with loss of smell haven't always gotten the care or the attention they deserve.

One of the silver linings of COVID is that it has brought so much attention to this sense because before then, there was me and a handful of other otolaryngologists in this country who had an interest in it. So before the pandemic, you know, I've been researching smell for over a decade now, but there were not a lot of other people doing it. And there was certainly not the same amount of interest as there is now.

Pre-COVID, how common was smell loss?

I would say certainly not as common as now, but it was out there. There are many viruses that cause, smell loss. You know, many other coronaviruses, rhinoviruses, influenza viruses, and there's many, many other reasons why you can end up with this type of problem. Endocrine issues, metabolic issues, any neurodegenerative disease. So we now know that smell loss can be the earliest sign of things like Parkinson's disease, Alzheimer's disease, Lewy body dementia, situations like depression, autism, schizophrenia. The sense of smell is really the canary in the coal mine, this harbinger of how cognitive function is occurring in the brain. And so there are so many different ways in which, you know, other disease processes can lead to sense of smell and vice versa, perhaps. And so although it was not nearly as common as it is now because of the prevalence of COVID 19, it is something that was affecting millions of Americans. I would say, you know, before COVID 19, a quarter of people over the age of 50 had some level of smell loss. So it was certainly still a big problem, just not talked about very much and not discussed.

Some of these patients that you've helped treat. You say that the impact on not being able to smell was something that maybe even they couldn't fully appreciate until they lost their smell. Any examples jump out?

Yeah. You know, I could talk for the whole hour about how much this impacts people. So there's very basic things. People realize they can't smell smoke. They can't tell when their stove has been left on. They can't smell if their food has gone bad when they take it out of the fridge. And so just very basic protective mechanisms, then they start getting anxious about their personal hygiene. Do I smell okay? I can't smell myself. Are other people going to smell me? I've had people come into the office just soaked in cologne because they are so worried that they smell bad to other people. You know, you can then think about how smell is related to taste. A lot of people think taste comes from the tongue and those very basic tastes like sour, sweet, salty, bitter, umami. Those come from the tongue. But everything else about the flavor of your food. Your ability to distinguish chicken from beef, from fish, your chocolate from vanilla from strawberry. That is all dependent on your ability to smell it. And then think about how across all regions of the world, all societies and cultures, how we come together as people, either family or friends or even with strangers. It's almost always over food and drink. And so when you start realizing people are not able to enjoy that in the same way and in certain cases become repulsed from that situation, of course, that leads to social withdrawal. And as social human beings, that can lead to depression, anxiety, all sorts of mental health issues. So the smell of coffee, the smell of walking through a forest, the smell of going to the beach and that salty, briny sharpness to the air, the smell of your baby as you smell their head. All of these aromas we take for granted. If you don't have that, people describe their world as having gone gray and really losing the joy of life.

It's interesting. There was a patient I still remember from when I was back in residency and she had a tumor, a meningioma. You're familiar with this. For our listeners, that's typically a benign tumor. But we also knew that her olfactory nerves, the nerves that are responsible for smell, went right through this tumor. And in order to remove the tumor, we would likely have to take those nerves. She knew that going in, and kind of like, just like you're describing Zara, it wasn't of huge concern to her when we told her this. But we followed her, you know, afterwards during her recovery. And then months and years after that, she would go through these periods of time where she would seemingly eat everything and she would come in quite overweight. This was her describing this. And then there were times that she came in nearly emaciated where she just wasn't eating anything. Just like you said, she couldn't smell her food. And at times, she would react by just simply eating things voraciously. And other times she she was nauseated by everything, seemingly. That was quite striking to me.

That's a very common phenomenon. People's weight can swing wildly. People are trying to gain some sort of satiation from their food, and so that's why they overeat. And then other people, especially those people with distortion of smell and taste, which is another phenomenon that can happen, sometimes just cannot stand eating anything that they used to really love and enjoy. It tastes terrible. Unfortunately, these distortions that can develop when there's damage to the olfactory system are never good smells or tastes. They're always these terrible smells. People describe rotting flesh or very chemical, sweet, sickly smells and tastes. They describe dirty socks, sometimes feces. There's always some terrible smell and taste. Can you imagine every time that you went to drink your coffee in the morning, it instead of smelling and tasting like the wonderful, warm, cozy aroma that we're all so familiar with, it instead smelled like paint thinner or tasted like socks. It's a really impactful thing.

Yeah. I was wondering if it was going to be an aberrant smell, why not have everything smell like roses?

That would be wonderful.

The Cinderella sense, as you've called it, though no more during COVID. When did this first sort of hit your radar?

My colleagues actually in other countries started to reach out to me. So, for example, I had a colleague from Italy send me I think it was a WhatsApp message, letting me know that he had lost his sense of smell. And not only that, but that many, many of his colleagues had also suddenly lost their sense of smell. And that made me realize, oh, this is yet another virus that's going to cause loss of smell and taste. And pretty early on, one of our residents here at Stanford, knowing I was an expert in smell, had connected me to someone at the CDC that was looking for some someone to consult with them on this issue as they started hearing about it also. And I, I started pretty early pushing adding this to our list of screening symptoms, because it seemed obvious that this was so much more prevalent of a symptom versus things that we were first talking about, like cough, shortness of breath, fever. So finally, after pushing them a little and certainly having other ENT colleagues in our organization, national organizations talking with them, they finally did add that to the list of symptoms.

When I first heard about this and, you know, I wasn't sure what to make of it, but I thought people might have significant sinus congestion, things like that, and that would interfere with their sense of smell. But it became pretty clear that it was more than that.

Yeah, certainly when people have sinus congestion and nasal swelling, that can lead to loss of smell. But in COVID 19 in particular, it's a different mechanism. Some people have swelling and congestion, but the majority do not. And the way in which the SARS-CoV-2 virus actually affects the smell system primarily is it actually binds to the supporting cells. And so the virus enters into those cells and causes a lot of inflammation. And that's why a lot of people have this sudden drop out and smell because of all that inflammation. The vast majority of people, probably 70 to 75% of people, within that first 7 to 10 days are able to bounce back and regain it. But what we now know is that there are people who continue to have persistent smell and loss dysfunction. And over time, there are definitely people who can continue to spontaneously recover over the ensuing months. But unfortunately, there is a significant number of people that have persistent loss of smell and taste or distortion. So a common phenomenon that we see is even in those patients who have right away regained their smell and taste, about 3 to 4 months after, will have some sort of secondary hit.

Why does that happen?

Our olfactory system has the inherent ability to regenerate over our lifetime. It does many, many times throughout our lifetime. About every 3 to 4 months, these nerves are dying off and regenerating. New nerves take over. And so that is why, you know, around that time, we might start developing this secondary phenomenon where the supporting cells that should have been able to send the signals to have those new nerves regenerate or send the signals to guide the right connection of those nerves, that's missing. And so that's when we start developing these problems.

Do those supporting cells themselves also regenerate over time?

They can, but they may not. And that's the problem overall. When people have this more permanent type of loss and smell and taste, that natural, inherent regenerative capacity of the olfactory epithelium of all these different types of cells, has taken a hit that's just too great that it cannot then bounce back and regenerate. And that's what a lot of our therapies are actually aimed at targeting, trying to kickstart that natural regenerative capacity to turn back on again.

Do you have a sense of how prevalent this is with COVID patients?

The initial kind of ancestral original variants and then even going through Delta, caused a lot. So, you know, estimates have ranged from 70 to 98% of patients with COVID had some level of smell loss initially, but about 75% of those will spontaneously recover. So the people who have long term persistent smell loss, what we would consider part of Long-Covid type symptoms. There have been different estimates about this too. A big meta analysis just came out recently, and it estimated that 5% of patients who had this happen, have a long term persistent problem. But I think that's actually a very low estimate. I think definitely millions and millions of more people around the world are now suffering from this problem.

I can't even imagine waking up to a freshly brewed cup of coffee or my mom's homemade chai and not being able to fully enjoy it. As Dr. Patel said, missing out on smell or taste can make the world go gray. The question now is this "Is there anything we can do then to restore our sense of smell after it's gone?" After the break, Dr. Patel is going to share how she treats patients with smell loss.

It's something that I describe to patients, like if you had a stroke and you lost function of an arm, you would go to physical therapy and do rehab until you could work that arm again. And it's the same thing, the same idea about your sense of smell.

That's coming up in just a moment.

And now back to Chasing Life. Remember Sakeenah Benjamin, who we heard from earlier? Well, she spent months with a warped sense of smell.

I really want it like a cheeseburger or some chicken fingers, like those sorts of things. Buffalo wings, all these things that you would just normally think about, like, "Oh, it's okay to eat. Like, sure, I wouldn't mind getting wings when I go out." I could not do that.

She drastically changed her diet, steering away from all of her favorite comfort foods. And at a certain point, she had had enough.

I stumbled upon a Facebook group. People were boiling like burnt orange peels and rinds of old fruit and all these things and just boiling it and putting their face over the water. I'm embarrassed to say that I did do it. I was very desperate at some point, and it did not work.

But one day, Sakeenah learned about a technique to essentially reteach herself to smell by sniffing odors that used to smell familiar to her.

Lavender candles, lavender essential oils, things that I thought smelled normal. Having that aroma go through my home at least once or twice a day, and just like trying to remember what they smelled like.

Sakeenah says that doing this exercise gave her a sense of hope. And thankfully today, her parosmia has improved. She's not completely healed, but she's finally able to enjoy some of her favorite foods again. Now, it's unclear if the time Sakeenah spent practicing smelling actually improved her symptoms. But we do know this based on existing research, some doctors are recommending a similar technique to their patients using both smell and memory.

So one major thing is something called olfactory training. That's really just a structured smelling protocol.

Here's Dr. Patel again.

It's something that I describe to patients, like if you had a stroke and you lost function of an arm, you would go to physical therapy and do rehab until you could work that arm again. And it's the same thing, the same idea about your sense of smell. So you basically take something that has a smell. Essential oils are easy because they hold on to a smell for a long period of time. The four that we commonly start with are rose, lemon, eucalyptus and clove. The reason we start with those is that they're in different categories of odor. So you're going to be stimulating different types of olfactory receptor neurons inside your nose. But anything that has a smell that you would recognize, you bring it to your nose. You just breathe normally, nice and slowly, deep in and out. But you focus your memory on what that smell used to smell like to you. That's a very integral and key component of the exercise because of that connection between our memory and our smell. And I have people do that twice a day, every day for a very long period of time, like six months, because the olfactory nerves are turning over and they don't all do that at the same exact time. So you want to cover all that time frame when all this regeneration is occurring, helping to stimulate that regenerative capacity.

You could just do this at home, you're saying?

Exactly.

Get those. So, rose, lemon, eucalyptus, clove. They represent four different categories of fragrance.

Yeah, you can switch those smells up. Like at one month and three months, you can change them, increase the the amounts of smells. All of those types of things can improve the efficacy of olfactory training. It's really just a matter of how much time you have to do it. But yeah, you can do all those things.

You said, I think 75% roughly of patients who have smell loss will recover on their own. Does this sort of smell therapy, is it helping people who would not otherwise recover or is it speeding up recovery?

It could do both, probably. But definitely,you know, when we've done these studies and there are lots of really high level studies I've run myself that show that people who are not spontaneously recovering. So one of my criteria for my studies is actually waiting six months after initial loss so that I don't confound my results with spontaneous recovery. And so this is helpful for people even at that point who have not been able to spontaneously recover on their own. This can help patients like that. It could maybe also help patients at the beginning speed it. But the key point is that you don't know which patient you're going to be. You don't know when you first get your loss of smell. Am I going to be one of those spontaneous recovery people or not? And the earlier you start with any of these interventions, the more likely they will be effective. And so I would encourage anyone who loses their sense of smell. It's so easy to do. There's no downside to doing it. Just start doing it right away.

Should anyone do. I mean, obviously, we're talking about people with smell loss, but even people who may not have smell loss but think that their smell is not as good. Is this something that can help my train smell for anybody?

It could. There are some people who just naturally do that as part of their profession. But if you wanted to try to increase your acuity, definitely just practicing with smells can do that.

Like people do a taste, like sommeliers with wine?

Yes, exactly.

How effective is that? What's the success rate?

Yeah. So it varies in studies. The numbers from different studies range anywhere from like 30 to 50% of people who compare it to not doing the training, people who were not able to recover.

So, I mean, that's that's not great, obviously, for people who are really suffering or are dealing with this, but still a good enough option, because why not? Is that, is that the thinking?

Yeah, exactly. We have lots of incremental improvement type of things, but nothing that you could just wave a magic wand and bring all the smell back. And there are actually some really interesting functional MRI studies that show that we really are doing something real here. You can take a person who lost their sense of smell, do a functional MRI, and there's this kind of chaotic, disparate array of connectivity in their brain that doesn't make a lot of sense. And then do this training for some amount of weeks, several weeks, and do that functional MRI again. And then just the entorhinal cortex where it's supposed to light up, that lights up. So we are definitely changing connectivity by doing that.

It's important to note that even though smell training is something you can easily do at home, it is still crucial to consult with the doctor if you experience, smell, loss or distortion. Your doctor is going to need to look into the root cause of the problem, which, as we learned earlier, could be a sign of other diseases. Plus, Dr. Patel says that smell training works best when it's combined with other therapies. One option she prescribes is a steroid rinse that's essentially rinsing the nose with steroid medicine.

Adding this steroid irrigation that does have increased efficacy, significantly increased efficacy versus just olfactory training itself. So that is helpful. And that is something that I tell all my COVID 19 and many other smell loss patients to do as part of their treatment.

Now, while talking to Dr. Patel, the doctor in me wanted to know if there's anything new on the horizon. Something that could provide even better outcomes for patients in the future. And Dr. Patel says she and others in the field are currently working on that. In fact, she recently completed a study on injecting patients with platelet rich plasma, also known as PRP.

People in orthopedics use this to inject joints to try to help with cartilage regeneration in mild arthritis. Esthetics uses it a lot. They, you know, do facials to try to regenerate the skin. They inject it into the scalp to regrow hair. And so there's a lot of other examples of how it is used. But I thought, well, if this can help with nerve recovery, that's really what I want for these olfactory patients. And so I ran a pilot study again pre-pandemic, and there was an interesting enough improvement in people's threshold in that very small number of patients I tried it in, that I thought, okay, this is worthwhile running a randomized controlled trial. And then the pandemic hit. And so I changed it to a specific COVID 19 smell loss study, and we've just wrapped it up, and it was successful. It was a successful trial.

Really? Fantastic. So patients tolerated it pretty well? And these were for the patients who had the most persistent symptoms?

Exactly. People who had already gone six months without recovery, had already tried olfactory training and steroid irrigations. But I really want to see, you know, what more can we do for people who have not been able to recover with these other things?

Just curious, you mentioned there's certain things that become clear don't work. Are there gimmicks or things that worry you that are out there, either home remedies or other things that are being touted?

Yes, many there are lots of people out there saying "This is the cure. This is the cure. Happy to sell" or charge patients for whatever. So there's something going around on TikTok about smelling burnt orange peels that was going to be the cure. And then there's other things. There's doctors, unfortunately, that are charging people for doing things like, for example, stellate ganglion block is something that has been in the news lately, which has no evidence behind it, but people are willing to pay for that. So I would really, you know, encourage people not to just listen to what's going on online. Even in these patient forums. It's not like people are trying to fool you or deceive you. It's that there is this spontaneous recovery that occurs. And if someone tried one of these random things at the time when they would have spontaneously recovered, they will tell people about it. They think they're being helpful, right? They think, Oh, this is what brought it back. But really, regardless of that, it could have come back for them. And so then people will flock to that idea and try that. And then and then, you know, notice that it doesn't help the majority of people. So really high level, randomized controlled studies are what we need to direct care. I think we have a responsibility as physicians certainly to not just do any and all possible things, but really counsel these patients on what is helpful, what has been shown not to be helpful. Many of these things out there, we have studied and they're not helpful or they can be harmful.

People who are listening right now, who hear you talking and say, "That sounds like me. I've been dealing with the smell, loss, taste, loss taste changes." What should they be doing?

Thankfully, now that we have so much more awareness, there are many other General ENTs that now know about olfactory training and all these other options. If someone can find an ENT around them, or even even better, a radiologist, someone like me who specializes in the nose, those people are much more likely to know about these different options.

And for the rest of us, people who haven't lost their smell, you should, as you say, do things to keep your sense of smell sharp. Get out there and smell.

Yeah, get out there and smell. And and I would say importantly, try to have some empathy for those people in your life, whether it's friends or family or even people that, you know, may just mention it in passing, that they don't have that ability because it is so meaningful and impactful on our quality of life. And so have a little compassion for those.

We still have a long way to go when it comes to treating smell disorders, but the research that Dr. Patel and others in the field are doing makes me pretty hopeful. She and an international group of experts recently published a large comprehensive review of existing studies on smell. The goal: help other medical professionals navigate this rapidly expanding field. We wanted to provide this episode today because I so often hear from patients who say it can be isolating, it can be confusing to face a problem like this with no known cure. That's why I think it's important for more people to know that there are options available that you can safely try at home even, and may lead to improvements. And for those of us without smell loss or smell distortion, I do think it's important for all of us not to take this sense for granted. In fact, while researching this episode, I read about an exercise I think we can all do to better appreciate our sense of smell. Try going outside for just a moment, closing your eyes and focusing only on what you smell. Try as best you can to block out all the other senses. I bet many of us are normally more focused on what we see or what we hear. But what if you try to just breathe in and just take in all the scents around you? I got to tell you, it's kind of magical. I've done it, and I'd encourage anyone who's listening right now to go ahead and try it. Thanks as always for tuning into this week's episode. And next week, our season focusing on the five senses continues with a fascinating episode about prosopagnosia. That's a disorder that makes it difficult to recognize faces. We're going to hear from people who have challenges recognizing friends, coworkers, even relatives, and how this perspective changes the way they see the world.

I got separated from my mom and I ran up to a woman who vaguely resembled my mom and, you know, begged her to pick me up and hold my hand. And she was very confused.

That's coming up next Tuesday. Chasing Life is a production of CNN Audio. Megan Marcus is our executive producer. Our podcast is produced by Emily Liu, Andrea Kane, Anne Lagamayo, Rafa Farihah, Xavier Lopez, Grace Walker and Eden Getachew. Tommy Bazarian is our engineer and a special thanks to Ben Tinker, Amanda Sealy and Nadia Kounang of CNN Health, as well as Rafeena Ahmad from CNN Audio.