№4 – How Smelling Improves Health with Dr. Michael Leon

Professor Michael Leon, with over 35 years of research at the University of California Irvine, delves into the close connection between smells and memory. Discover the potential of olfactory enrichment in combatting dementia and improving other health conditions.

EPISODE LINKS:

• Michael’s Blog: https://stopmemoryloss.com
• Memory Air Device: https://learn.memoryair.com
• ResearchGate: https://www.researchgate.net/profile/Michael-Leon-2

Your support keeps our olfactory tales alive. Until next time, happy smelling!

Transcript

Olfactory Enrichment: Boosting Memory and Health with Dr. Michael Leon

Dr. Michael Leon: It's the human mind really needs a great deal of olfactory stimulation.

[Intro music}

Tanya Mironova: Welcome to Not -a- Perfumery podcast, where we discuss smells in connection to wellness, art, and innovation. My name is Tanya Mironova. I'm an olfactory art educator and your host today. Our special guest is Professor Michael Leon from the University of California, Irine. Michael, welcome to the podcast. 

Dr. Michael Leon: Glad to be here.

Tanya Mironova: I have to tell you one thing. I've been exploring olfaction and its different aspects for almost a decade now. And at times I started to feel a little bored because I personally either have limited access to the really innovative research or the research is limited. Actually when you make your presentation at the Barcelona olfactory congress this year I felt alive. Before we start talking why your research and why it is so inspiring to me let's first talk a little bit about you. So, how did you decide to start exploring the olfactory realm of science?

Dr. Michael Leon: Well, we have been involved with a long term study of olfaction, that is how chemical information gets turned into a perception or a feeling of an odor. And that was basic research. And we also were doing work with humans to see if we could get them to learn to become attracted to odors on the first day of life.

Dr. Michael Leon: And it turns out the mothers put out odors that the babies are attracted to, and they learn this on the first day of life. So we became interested in the the importance of odor early in life. And we also became interested in this vast literature in neuroscience that shows that environmental enrichment is really important for rats and mice brains. And subsequently we turned that into human brains. And so we knew that there were various animal models of autism. They changed the genes or they give them toxins and the rats and mice turn into good animal models of autism.

Dr. Michael Leon: They have the same kinds of social problems that children with autism have. And all of these human like symptoms could be seen when the animals were living in a restricted environment. That is a little box cage all alone with nothing much to do. But when they were brought into what's called an enriched environment much bigger cage, with many more rats or mice and many more things to do. It turns out that their brains become much more competent. They become much more complex and they're able to have all of these genetic or toxic exposures and they don't have all of the symptoms that they had when they were in the box cage. And so it's possible that humans are also somewhat restricted in their experiences, and they too could be better if they had environmental enrichment.

But in our modern affluent world, everybody thinks that we get plenty of stimulation. And so there really nobody tried to use this for humans, but we thought that maybe they weren't getting the right kinds of stimulation. And the critical part of the stimulation that we designed for children with autism is to have multiple exposures to different odours over the course of the day. That's important because the olfactory system is the only sensory system to have a direct superhighway connection into the memory parts of the brain and the emotional part of the brain. All the other senses have to go through the side streets of the brain so called thalamus and they consequently have less impact on these areas. So if you lose olfaction for any reason and people have as they age, their olfaction gets worse and worse, but many neurological and psychiatric problems are also associated with olfactory loss. Autism is one of those.

And virtually all neurological disorders and somatic disorders as well are accompanied by olfactory loss. I've counted 89 of them and only two where they've looked have not had olfactory loss. Anorexia, bulimia, blepharospasms, schizophrenia, stroke, depression, Alzheimer's disease, all of these things are associated.

Tanya Mironova: And Michael, sorry to interrupt you, but I've also noticed in one of the papers that your colleagues and you mentioned that the person's susceptibility to even some drug substances or alcoholism could be correlated with a reduced I would like to say reduced pleasure from smells, but reduced ability to smell things, right? 

Dr. Michael Leon: Yeah. Absolutely. Parkinson's disease. All of these things are associated with olfactory loss. And so we put together a kit for parents, and we gave the kit to parents of children with autism. And these are seriously affected children. And over the course of six months, the parents gave them environmental enrichment that was focused around multiple odours, but also visual and auditory and tactile stimulation.

 And so over the course of six months, they had dramatic improvements in their autism like behaviors. And it also improved all the ancillary symptoms that accompany it. Problems with sleep, problems with eating, problems with mood and so forth. And so this is, this is really It gave us an insight into what we thought that environmental enrichment could do.

Tanya Mironova: Well, I start immediately thinking that in this mice experiment you're saying that mice did have a lot of different stimuli. So it wasn't just olfaction we changed, they got new environment, they literally got friends. And yeah, actually they got new equipment, maybe like new training equipment. I don't know, like the lighting was different many factors changed and to me it looks like it was really a big leap of faith to start thinking that it was the olfactory enrichment which played a crucial role, not something else. I just wonder, what made you think in the first place like back years ago, that it was the olfactory enrichment which played the key role 

Dr. Michael Leon: So there was actually a study that was published looking at the role of olfactory enrichment alone on mice and it duplicated the entire environmental enrichment phenomenon. So with just multiple odours on a regular basis, there were actually aged mice, they had improved memory and they also improved their ability to produce new neurons, which can underlie a much greater functionality in the brain. And so we thought that maybe if we just used olfactory enrichment we can improve the brains of aged humans.

And so we did that. We gave humans olfactory enrichment with a diffuser when they went to bed at night. And the diffuser was on for a couple of hours, and every night they had a different odor. So they got their enrichment in that way. And again after six months they had a dramatic improvement in their memory. It was 226 percent better than the controls. 

Tanya Mironova: Yeah, that's really big. I was so surprised to read the study and see these figures. 

Dr. Michael Leon: So that's enormous. As far as I know, that's the largest improvement in memory that anyone has reported for healthy, older adults. 

Tanya Mironova: And, you know, knowing what we now know seems so logical all what you've been doing. And it seems so right to use our senses to cure us. But we start immediately wondering, reading your research, I start wondering myself, like, why haven't we done it earlier? Why haven't we started exploring this field and using an olfaction, an olfactory enrichment?

Dr. Michael Leon: So I often hear that when I describe all this to people.Tthey want to know why everybody doesn't know about this. It seems so obvious, I guess. But I think there is some, there are some scientific findings that people are ready to hear, and then there are some findings that people are not ready to hear.

And so it was clear that people really liked to hear this idea. That is, they were ready to accept it. And it's over, no, it's almost 300, 000 people have read the article that we published in August, which is, you know, very, a lot of people. And. You know, there've been a couple of hundred media stories.

There, there's just a lot of interest in it. And I think it's because people have evolved to be drawn to odors. And, and so, you know, when you smell something, you, there's actually a reflex that increases your sniffing if it's a pleasant odour and decreases your sniffing if it's an unpleasant odour. And, you know, when you think of it, almost all consumer products: shampoos, creams, and stuff, all of those are scented. And the reason is, is that most people won't buy it unless it is scented. So I think people just like the idea of odors, and that many people have odors in their house. They have scented candles, they have an essential oil diffuser and I think people just like them. I think the reason is, is that we've evolved so that we're drawn to odors and the odors keep our minds. Fresh and, and, and so when people hear about this, they go, yes, I, you know, I always like odours and I really, I'm happy to hear that these things are, are will help. Yeah. 

Tanya Mironova: And you know, it's very interesting that today many people prefer scented products. Scented consumer products to non scented products. 

Dr. Michael Leon: Yes, they, most of them do, and actually some people like even stronger smells, and so some of the consumer products people are putting out extra odor in their in, as one option for their product. And yes, there are people who don't like any of the odors, but most people just are, are drawn to these odors and, you know, just trying to find a shampoo that's not scented. It's, it's very, very difficult. 

Tanya Mironova: And so since we're discussing smells and discussing the strength of smells for your research and your papers, when you are saying strong smells, what is strong, what is considered strong? 

Dr. Michael Leon: So we use it at full strength. So right out of the bottle.

Tanya Mironova: Right. So not diluted.

Dr. Michael Leon: And It's we can do that while people are sleeping because the odour sensing system is not connected to the sleep systems, or the thalamus, really, which is connected to the sleep systems and therefore you can't design an alarm clock with odours. That's been tried because deaf people can't hear the alarm, the sound alarm and people have tried even frying bacon and still they haven't been able to wake people up. 

Tanya Mironova: Unless they're vegans, I suppose. 

Dr. Michael Leon: Possibly, but so, so we were able to have it strong and, and that probably was a, a good thing. We've now designed a device that puts out 40 odors a night while you're sleeping, twice a night while you're sleeping and it blows it right at you.

 It sits on your nightstand and blows the odors at you and then clears it out so that you're, you're not smelling multiple odors simultaneously. 

Tanya Mironova: And so why did you decide to proceed with 40 smells, not 4, not 50, not 100? 

Dr. Michael Leon: We think 40 is important because a group in South Korea have shown that giving demented older adults 40 odours twice a day dramatically improves their memory on five standard memory tests and also improves their depression symptoms, which I think is really interesting.

Dr. Michael Leon: And as we speak, olfactory enrichment is now the most effective treatment for dementia for people with Alzheimer's disease. And so you know, we've always wanted an Alzheimer's treatment that was highly effective, safe, low cost and easy to use. And that's what the odors turned out to be.

 And the recent drugs that have been approved are ineffective, dangerous, high cost, and difficult to use. So the reason we do it at night is because we want to have 100 percent compliance. And if you ask people to do something, anything during the day, even people who've had heart attacks, if you ask them to take a low dose aspirin every day, half of them don't do it. It's just hard for people to do something like that. 

Tanya Mironova: Anything but saving their lives. 

Dr. Michael Leon: So right. So what happens is that at the start of the month, you press a button close it up. And when you go to sleep and an hour after that, the odor will come on and it'll come on every night for the next month.  And, and then you put in a new set of odors and. Press a button. And then again, you don't have to do anything for a month. And so that solves the problem of actually getting people to do things. And so, I mean, it's, it's. You know, you could see people using a few odors, but even with a small number, people get, they, they just don't do it.

Tanya Mironova: And, you know, for me, it's very fascinating that it turns out that you could actually do nothing, just be a passive observer, or in this case, a passive sleeper and good things will be happening to you while you're asleep. Why is this so? It's very interesting because, you know, after having spent some time with perfumers at the educational institutions, like Cinquiéme Sens, for instance, I worked a little bit for, or the Perfumery Club of Odormania, which me and my friend Ludmila launched in Belarus in Minsk. And it is especially interesting that people actually love Smelling things when they start smelling it was clear that there was something behind it. Something really strong, but I didn't know what was that. So it seems that these individual attempts of making their mood better really worked for them and they would have worked even if they were not conscious at the moment of smelling.

Dr. Michael Leon: Yeah, so there's, there's now about 20 studies. showing that olfactory enrichment, some people call it olfactory training with various numbers of odours and various ways of doing it. And they've shown that over time you see improvements in both brain and cognitive behavior and depression symptoms.

Dr. Michael Leon: And that is consistent with what we're finding and it's always good to, you know, appreciate individual research reports. But what you really want to do is to look at an entire literature and see if there's a consistent finding in it and that's what is the case with olfactory enrichment.

Dr. Michael Leon: There's just now quite a number of reports and they're all showing very similar kinds of things. You know, for example. People who are training to become master perfumers.

Tanya Mironova: Oh yeah, finally we got there.

Dr. Michael Leon: So the way that you train, of course, either to be a master perfumer or a master sommelier, a wine taster. The way that you train is you smell dozens and dozens of odours every day for months and months and months. And people have looked at the brains of others who've been in these, and typically they're young adults who go through this kind of training. And in those cases you see that there's an increase in the size and functionality of the memory centers of the brain.

Dr. Michael Leon: And you know, that is again consistent with the whole idea of olfactory enrichment, improving brain and behavior. 

Tanya Mironova: You know while I'm listening to you, I recall from my training experiences. And I had a few in different institutions and different settings. But the main point was, smell should not be considered passively, you should not be smelling passively. This is something I was taught. And now after reading the research and talking to you, I really understand that the benefits of the olfactory training are not directly connected to whether you smell it passively or actively. 

Dr. Michael Leon: So there are two things that are going on when you're training to become a perfumer or a sommelier.

 One is that you really want to be able to identify the odors. So when a sommelier tastes some fine wine, they go, oh, I smell the scent of raspberries and leather and hay. And, and so that's the, they're really learning to identify odors. And in order to do that, they have to sniff the odors, and they have to sniff many of them.

 So I think there are two processes going on. One is the sniffing, and that stimulates the brain. And then on top of that, there's also learning, which also improves the brain. So, and in the memory areas in the brain. And so it's it makes a lot of sense that the sommeliers in training and the perfumers in training are going to get a great deal of olfactory stimulation, but they're also going to get a lot of olfactory learning.

Tanya Mironova: So for that identification purposes, it's necessary to inhale things. And you know, it's super cool that you could technically be asleep, so inhale things passively and it will still work. Right. So to me, it seems like double win. Right. 

Dr. Michael Leon: Right. And you're clearly not going to learn to remember which odors are which if you're sleeping.

Tanya Mironova: So. It seems like the purpose of this device is to get some other benefits. than learning smells, right? So yeah, when it comes to such an innovative device, I truly believe that you need to build the new chain for distribution. And, of course, when it comes to the markets which are far from the US, where this device will be probably presented first, it's a story where you have to put a lot of effort into making all things work.

So what's in your idea, what is going to be the distribution model and when customers from abroad will be able to get access to the actual device and start using it? 

Dr. Michael Leon: So starting in February the devices will be available. The devices are called Memory Air, and if people are interested in being notified, if they're interested in ordering it, they can go to Memoryair. com, and that will allow them to get more information, to sign up to be notified when it's available. And so at this point, it's all directly web based sales. And at some point we'll use other ways of distributing and selling it. 

Tanya Mironova: Yeah. And I think that by these point, some people think that, well, if we don't have any sorts of problems, which you mentioned in the podcast, So we're not on the list with this device. So what do you think, would everyone benefit from its use or there are some specific categories of people who need to have it first and really need it more than others? 

Dr. Michael Leon: Well, our guess is that everybody is deprived of sufficient olfactory stimulation if they're living in the first world. And our brains evolved at a time when there was plenty of stimulation of the olfactory sense.

And so we think that everybody is deprived of olfactory stimulation and probably everybody would benefit from having this from when they're children to the end of life. You know, everybody would be better off, I think, if they had better brains and particularly better memory. And so, I, I think there's going to be benefits for young adults who want to be competitive in this world.

And as people hit the age of 60, when both their olfactory sense and their memory starts to go south, they're going to want it. And of course people who've developed problems like Alzheimer's disease or Parkinson's disease those too will be people who will want to have it to improve their memories.

So I, I, you know, I, I think there's just a great deal of opportunity here for people to improve their minds, which would be great. And it looks like it also may improve the amount of sleep that you get. And it may also improve symptoms from other disorders that we haven't tested yet, but, but we plan to 

Tanya Mironova: So Michael, you are saying that it's very important to have as many different smells as possible, but if I got it right, the initial idea of the device of the Memory air device is to have 40 smells. So for how long could these 40 smells be considered new smells to someone? Or you think that because they're used at night, maybe it's not that important to change them often? And they're still new to a person for a longer time, just because it's a nighttime use.

Dr. Michael Leon: Yeah. So from our perspective, it probably is not important which odors you smell. So when people are training to become perfumers or sommeliers, they have kits that they use to, to have individual odors. And these can be complex, they can be simple, they can be a single molecule, they can be a mixture of molecules. And they come from various families of odours.

And so people have been sort of trained over the years to think of special properties of different odours. And that may be the case for, for some of these odours. But what we think is important here is to get different kinds of odors. So you want as much differences and novelty and, and changing the odors as much as possible.

And, and that seems to be the critical aspect of this rather than special properties of individual odors. So our initial odors will be 40 odors but we plan to have different sets of 40 odors. And so there will be plenty of novelty, plenty of new odors and plenty of chances to stimulate your brain.

Tanya Mironova: And so now it seems to me that the whole field of olfaction is really evolving right now. It just happens in different countries and we're getting some practical devices like yours or we're getting just information which could be used. And so right now my question is, what, in your perspective, are the future fields for the research in the area who are going to be making new big things in that field?

Dr. Michael Leon: So there's a possibility that all of these diseases that are associated with olfactory loss, so it could be just a coincidence, it could be, you know, random correlations. or It could be that the olfactory system is just very sensitive. So if you have one of these diseases, you know, it may be inflammation is causing the olfactory system to deteriorate. But I think the most interesting possibility is that there is loss of olfaction, and the loss of olfaction makes you vulnerable to expressing the symptoms of all of these diseases. And this idea really comes from a phenomenon that's seen for people who have Alzheimer's pathology. So if you look at their brains, they are full of amyloids and tangles and they look like a typical Alzheimer's brain, but they don't have the symptoms, right? They don't have memory loss. And this phenomenon is called cognitive reserve. And the reason it's called cognitive reserve is that some people have had lives that have been enriched. And so they have had a high level of education. They've had a career that involves a great deal of intellectual stimulation, and they may get a great deal of social stimulation.

 And so if you've had environmental enrichment over the course of your life, you can have the disease. So these people have the, all the hallmarks of Alzheimer's disease, but they don't have the symptom of memory loss, and it may be that many of these disorders are preceded by the loss of olfaction. And it makes them vulnerable to expressing the symptoms of the disease. And so our notion is that maybe you can prevent the expression of these symptoms by giving yourself olfactory enrichment and that may prevent you from getting this increased risk of, of the symptoms when you have the, the actual pathology in your body and brain.

And so it'd be great for experts in these various fields: Parkinson's disease, stroke, blepharospasm, depression to see if olfactory enrichment can prevent the expression of these symptoms so that even if you have all of these problems, you won't have the symptoms of those problems. So I think that's going to be the most interesting thing to come out of this. So It's not just memory, it's not just depression, it could be that it, it is critical for maintaining your ability to ward off expressing the symptoms of these disorders.

Tanya Mironova: Wow. I've never thought about something like that. So I definitely, like, need more time to think. 

Dr. Michael Leon: It's a, it's a new idea, so it'll take some time to sink in but it's, it's really I think, a really exciting possibility.

Tanya Mironova: Well, actually, after this discussion, I feel that maybe more people will start thinking about their olfactory abilities, olfactory enrichment, about the landscape they are in. And yeah, because it's well known due to many experiments that right now people would prefer to lose their sense, their olfactory sense rather than losing their mobile phone.

Dr. Michael Leon: Well, if you ask people which is their least important sense almost all of them say it's the olfactory sense. And. It may be, though, that you really need a great deal of olfactory stimulation to live the best life you can live. And it may be that the sense that people think is the least important could turn out to save their mind.

Dr. Michael Leon: And in that case, it would be the most important sense. You know, some people just do it. Because they think it's pleasant but the, the benefit is probably that they're improving their brain while they're enjoying those odors. 

Tanya Mironova: Yeah, Michael, these are the golden words. Thanks for coming to the podcast and for your research.

Tanya Mironova: We will provide all the links in the description. I am really expecting to see you in future episodes. Thank you. 

Dr. Michael Leon: My pleasure. Nice to meet you. Nice to talk to you.