Front Burner - Front Burner Introduces: The Dose | What does my mental health have to do with the health of my gut?

Episode Date: January 1, 2024

The Dose is a weekly look at the health news that matters to you. Dr. Brian Goldman brings you the best science from top experts in plain language. This episode examines the many factors that influence our mood, including one we may not think about: our diet. It turns out the emotions you feel have a lot to do with what’s happening in your gut, or your gastrointestinal tract. Dr. Mary Sco., a family doctor with a PhD in nutrition, breaks it all down. More episodes of The Dose are available at: https://link.chtbl.com/PNoxliEC

In the Dragon's Den, a simple pitch can lead to a life-changing connection. Watch new episodes of Dragon's Den free on CBC Gem. Brought to you in part by National Angel Capital Organization, empowering Canada's entrepreneurs through angel investment and industry connections. This is a CBC Podcast. Hi, Damon Fairless here. We have a special bonus episode for you from the CBC podcast, The Dose. The Dose is a weekly look at health news from someone inside the field. Dr. Brian Goldman brings you the best science from top experts in plain language. It's the kind of advice and insight you won't find anywhere else.

In this episode, what does my mental health have to do with the health of my gut? Dr. Goldman speaks with Dr. Murray Skow, a family doctor with a PhD in nutrition, to break down the many factors that influence our mood, including one we may not think about, our diet. Turns out the emotions we feel have a lot to do with what's happening in our gut. Have a listen. Hi, I'm Dr. Brian Goldman. Welcome to The Dose. One in five Canadians has or has had a mental health disorder, making it one of the leading causes of disability in this country. That's according to the Mood Disorder Society of Canada.

We think we know the causes. Social media, the pressures of post-pandemic life, even smartphones have been implicated. But the emotions you feel may actually have more to do with what's going on in your gut. No, not the metaphorical trust your gut gut. I'm talking about your gastrointestinal tract, where gazillions of microorganisms live and apparently trigger emotional states like anxiety and depression. So this week we're asking, what does my mental health have to do with the health of my gut?

Hi Mary, welcome to The Dose. Hi Brian, thanks for having me. Have you ever noticed that what you eat has an impact on your mental health? Absolutely. I feel like part of the biggest motivation for me to put the time in every day to meal prep and to prepare healthy food for myself is because I feel fundamentally different and I feel like I can live my life better by doing so. What foods are your go-to foods for a better mood? Oh, a lot of it is making sure that I'm eating low glycemic index carbs that don't cause blood sugar spikes, making sure I'm getting good omega-3 fatty acids. And one of my favorite foods, leafy green vegetables like spinach.

Those are some of my staples for keeping myself well. I haven't heard dark chocolate yet. I know. It's a little bit of that too here and there. Okay. That's the more fun side of the subject, but there's a serious undertone to this, and that's why we've come to you. Before we begin, can you give us a hi, my name is, tell us what you do and where you do it. Just ad lib. Sure. My name is Dr. Mary Sko. I'm a family doctor with a Ph.D. in nutrition. I recently completed my residency at Women's College Hospital in Toronto, and I'm currently doing some additional training south of the border at the Eastern Virginia Medical School in Norfolk, Virginia.

OK, let's start at the beginning. How can what we eat affect our mental health? So what we've learned in recent years is that there's all this increasing evidence that shows that what we eat affects how we feel every day. For example, there was one study where they took about 60 people with moderate to severe depression. Some of them were on antidepressants, some of them were not. And for just 12 weeks, they put them on what they called a modified Mediterranean diet. And what they found was that after those 12 weeks, one third of those patients were able to put their depression into remission. And this isn't the only example. Similar research has showed even after only three weeks in young adults, they show that depressive symptoms were significantly reduced. And these are just two examples. I feel like every month when I'm

reading the latest nutrition science literature, I see more and more of these studies being published. But the best part is this actually isn't a new idea, even though the evidence is only starting to accumulate now. We know that in 1621, there was this scholar at Oxford. His name was Robert Burton, and he wrote a 900 page treatise on what they then called melancholia, or what we would generally call depression. And he gathered information from all of the sciences of the day, which were psychology, physiology, also astronomy, astrology, theology, demonology, interestingly. And he wanted to explain what this entity was. And what he concluded is that there were really six things at play here. And he identified them as being exercise, sleep, waking, perturbations of the mind, air, retention and evacuation. And the last one was a diet.

So the point is nutrition and mental health is this connection that people have actually been writing about for centuries. But only now are we getting this evidence to accumulate to support this connection. In the studies that you've looked at that linked what you eat to your mental health, how did the effect of the diet compare to, say, antidepressants? Well, it's interesting. In some of the studies, people are already on antidepressants. So it's not a matter of, like, is one better than the other? It's a question of augmenting a tool that we're already using, which is very encouraging. We also know that antidepressants work well for some people, but they don't work well for everyone. So I kind of also see it as an alternative for those for

whom antidepressants aren't working. There's never been a head-to-head trial that has compared, you know, one arm with the people on antidepressants versus another arm with the people on diet. But the way I see it is for those with mild depression who perhaps might not be ready for an antidepressant, it's a good thing to try. And even for those who are already on antidepressants, the evidence shows it can have additional benefits above and beyond the medication. What foods are we talking about that have been shown to be beneficial to your mood? Yeah, so in these trials where they're testing these so-called modified Mediterranean diets, what they're really doing is, first off, people are eating a lot of fruits and vegetables. In fact, in these studies, they were eating nine servings of fruits and vegetables every day.

They were also eating a fair number of servings of whole grains every day. So things like oats, barley, that sort of stuff. They were also eating nuts every day. Then every week, they were eating about three to four servings of legumes or beans, two servings of fish, and then small amounts of low-fat dairy products, lean meats, and eggs. And importantly, they also encouraged the people on these diets to eat minimal amounts of treats foods like sweets and refined carbs and fast food and processed food and, of course, sugary drinks. When you put this all together, to be honest, it kind of just looks like a generally healthy diet. And it's not that far from what Canada's Food Guide recommends. But when you deconstruct it, I would say that the common denominator amongst the foods that are the most prevalent in this diet is really dietary fiber.

You're going to get lots of fiber from those fruits and vegetables, from those whole grains and from those beans. And that's the thing that I think is really making the difference here. So what is the connection between fiber and a better mood? In order to understand and to think about how fiber affects mental health, we have to start by talking about the microbiome. So it's a little known fact that we all carry approximately one half pound of bacteria around inside of us. And that half pound of bacteria, also known as the microbiome, lives largely in our large intestine. And the truth is, we could not survive without these trillions of bacteria. They help us digest our food. They help and form and strengthen the lining of the gut wall. They out-compete bad bacteria.

And they're basically like the thermostat that controls the level of inflammation in our body. However, within this half pound of bacteria, there is a mix of the good bacteria that serve us as well as some bad or less optimal bacteria. Now, every time you eat, you are not just feeding you. You're also feeding the trillions of bacteria that live inside of you. And certain foods feed good bacteria, while other foods feed bad bacteria. feed good bacteria while other foods feed bad bacteria. Now here's where the fiber fits in. Good bacteria love to eat fiber. So whenever you eat fiber, your good bacteria then also eat fiber. But they share their excitement about this by sending signals to your immune cells that live right next door. Those immune cells then respond and release their own signals that travel throughout the

bloodstream and eventually reach our brain, where they can then influence our mood and our anxiety levels. So your gut talks to your brain by way of your immune system. Does your brain talk to your gut? Absolutely. The relationship is bi-directional. And we know that, for example, when we're stressed, our body activates our sympathetic nervous system. That is our fight or flight system. And we know that evolutionarily, when a human encountered a stressful situation, it might have been something like an encounter with a wild animal, say. So the body is designed to protect us from these sorts of scenarios. So let's say we encounter a stressful wild animal and we need to run away from it. Well, the body is strategic.

It wants to turn off the things it doesn't need and focus only on what it does need for survival. So when you're running away from that wild animal, you don't need to digest food. So when the sympathetic nervous system is activated, the gut is really turned off in a way. And this is part of how what's happening in our brain influences what's happening in our gut. This is a little bit of a chicken or egg kind of question, but is it possible that when you're under stress, you crave the wrong kinds of foods which promote the wrong kinds of bacteria? Oh, absolutely. There is definitely that element as well. It is not all science. It is partially social. And I definitely

think that there is that confounder as well. So yeah, no, we can't preclude that. So let's talk about fiber and what is it about fiber that good bacteria like it so much? Well, the funny thing about fiber is when I first started studying nutrition, it was not a cool or hot nutrient. It was very underrated. And in fact, it was seen as being an anti-nutrient. Because the thing about fiber is it's not a vitamin. It's not a mineral. We don't even absorb it. It's just this thing that passes through us and cleans us out. But in that, there is also something very important. Because yes, it's just passing through us.

Yes, we're not absorbing it. But again, it's feeding those bacteria. And those bacteria control so much of our health. And if we don't feed them, they can't do what they need to do for us. So that's what it is. Fiber, it's not absorbed. It's not for us. It's for our bacteria, which then do things for us.

So it's really that notion that it is an anti-nutrient. It's something that's passing through our digestive tract, but feeding those little bacteria along the way. And what are some of the best sources of dietary fiber? Yeah. So when I think about fiber, one of the top food groups that I always think about, more so than anything else, is actually your beans, your legumes, your lentils, and your chickpeas. You can't find more fiber in any other type of food, and that's kind of the most fiber you'll get from a single source. Nuts, especially almonds and pistachios, even peanuts have a lot of fiber. We know that whole grains like oats, barley, bulgur, even corn have good amounts.

Then among vegetables, it really depends. So there are certain vegetables that are very high in fiber, notably cruciferous vegetables. Those are some of my favorites like broccoli, cabbage, Brussels sprouts. And then other things, other vegetables like green peas, artichokes, and pumpkin, interestingly, are very high in fiber. Then among fruits, your top contributors of fiber are things like berries, apples, pears, avocados, and mangoes. The other place where you can get quite a bit is in breakfast cereals. Many have notable amounts, but you have to read the label to see how much is noted because you would have to take a closer look. I can't really give you a rule of thumb for how to find which one would have the most.

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together. To listen to this podcast, just search for Money for Couples. Now, I want to spend a little bit of time talking about that half pound of microorganisms that you referred to in our large intestines, the microbiome. You've started to mention a connection between that and mental health through the immune system and through inflammation. Can you say more about the effect that the microbiome has on our physical well-being as well? Yeah, so it does so much. We know that, like I said earlier, it really is like the thermostat on the level of inflammation in the body. There have been links between the microbiome, not only in mental health,

but in terms of risk for diabetes, in terms of risk for heart disease, in terms of our weight. We know that all of these factors are influenced by what is living inside of us. And we also know that the microbiome isn't just communicating back to the brain through the immune system.

We also know that it's literally connected to the brain through nerves and wires, and the microbiome influences what signals those nerves are sending. We also know that the gut is connected back to the brain through hormones, and we know that the microbiome is influencing those hormones as well. So the microbiome is not something that we think about or not something that, you know, it's not an organ. It's not something that you physically can see or touch or dissect in anatomy lab, but it's there and it's really fundamental to our biology every single day of our lives. And is diet the major factor that influences the composition of the microbiome in one person to the next? The way I see it is diet is one of the things on a daily basis

that we can alter to influence it. But your microbiome has been determined by so many factors going back to when you were born and how you were born. So we know, for example, babies that are born by C-section start with a very different microbiome than babies who are born vaginally. We know that breastfeeding, breast milk has special probiotics and prebiotics that you can't get anywhere else. So a breastfed baby is going to have a fundamentally different microbiome than a formula fed baby. Then we know if you grow up on a farm versus in a city, that affects your microbiome. If you grow up with a pet versus not having a pet, that affects your microbiome.

So there is a very, very long list of factors that influence the microbiome. Diet, I just see as being the thing on a daily basis that is either pushing us in a good direction or pushing us in a less ideal direction. So I would imagine then that ethnicity would have a major impact on microbiome on a very large scale. Well, I would say, yeah, it really is more like country of origin and location of where you're living, because that influences so much about what you're being exposed to and what sort of environment you live in and what sort of bugs you're thus being, you're encountering on a daily basis. So for sure. So to sum up to this point, our general health and our mental well-being is at least

partly determined by our microbiome. Our microbiome connects to our immune system, which sends signals to our brain. I think I've got all of that. Given all that, what's your advice to people who are thinking about how their diet might be affecting their moods? I think anybody who's struggling with their mood in any way could see this as another tool in the toolkit, right? I don't want to minimize people's mental health experiences because I know that it's really serious and there are many factors at play. And your diet is just one factor among many. That being said, I see diet as being something that can help promote biological resilience. And if

you're struggling with something, you want to do everything you can to make yourself more resilient to whatever challenge you're up against. So I would say if you're having any kinds of issues, and even if you're not, because prevention is the best cure, right? Doing these things is helpful. And keep in mind, increasing your dietary fiber intake, it's not just going to decrease or increase your resilience towards mental health. It's also going to decrease your risk for diabetes, for cholesterol issues, even for keeping a healthy weight. The list kind of goes on and on and on. There's nothing that doesn't improve when you make these very generic dietary changes. So I would say if you're thinking about it, try making a few small changes. You don't have to overhaul everything. You don't have to reinvent yourself overnight.

But a few small changes can often go a long way and can inspire you to make more changes down the road. When we talked about mental health and the connection between that and your microbiome, we were talking about depression. What about anxiety? Because that's pervasive as well, microbiome. We were talking about depression. What about anxiety? Because that's pervasive as well, isn't it? Absolutely. So anxiety and depression, sometimes they're two sides of the same coin. And sometimes they're very different entities. There is also fascinating literature looking at anxiety and diet. I will say, I want to preface this, the literature is not as rigorous and robust. So for depression, we have randomized controlled trials. That's the highest level of evidence. When it comes to anxiety, we have

association-based studies and we have mechanisms. But what I will say is that when you look at those association-based studies and when you look at those mechanisms, there's a clear connection between sugar and refined carbohydrates and anxiety. So I do think that for anyone who's struggling with anxiety, being mindful of those things can be very important. And the interesting thing is, because of how our hormones work, it's a little bit of a delayed effect. Because when we eat sugar, our body releases insulin. And then hours after our body has released insulin, our body actually releases adrenaline, which is the counter-regulatory hormone to insulin. So it's not that you

immediately eat the food and feel bad. We all know how we feel after we eat sugar, right? Like we feel really good, but it's those three or four hours later where that adrenaline creeps up and sometimes anxiety can creep up with that. Then there are also very obvious things that we eat that can contribute to anxiety, or one I should say that we drink is like caffeine. We know that caffeine can take a worrier and make their worrying even worse. And then of course, there's things like alcohol that can contribute as well. But the one that I think I'm hoping

we'll see more research to demonstrate more rigorously is this connection between sugar and refined carbs. I'm talking white bread, white rice, crackers, chips, all those things, and anxiety, because I think there's some exciting mechanisms there. Well, we look forward to hearing more about those studies in the months and years to come. When we think about good bacteria, we often think about probiotics. How about those? How beneficial might those be in improving your mood? There are meta-analyses. So those are big studies, the combined data from many, many little smaller studies, which show that probiotic supplements can benefit mood and species of bacteria at different doses. And

there's a lot of complicated stuff going on that we need to sort out before we can tell people that they get a guaranteed benefit from walking into a store and buying a probiotic and starting to take it. That being said, you know, I like history. I'm giving you all these anecdotes. There's this interesting history behind probiotics and mental health. Once again, this is not a new phenomenon. A hundred years ago, people were selling probiotic supplements for mood. And in 1932, there was this ad series in the New York Times that actually recommended an acidophilus milk drink, which claimed that if you drank this for 30 days, it would produce a, quote, cheerful

outlook. Nothing is new. All of these things have been tried and now they're being revisited. But I would say for now, the superior way to improve your microbiome is not necessarily to eat this probiotic and put the bacteria in, but rather to grow the good bacteria that you've already got. And that's what you do when you eat fiber and vegetables and all those healthy foods. I think it's a little bit more efficient than taking a supplement, even though, you know, supplements are easy. We would all love a, you know, a silver bullet that would solve things quite efficiently. The kind of more intent labor intensive way of chopping those vegetables

is probably the surer way to improve your microbiome. Where do you recommend people who are listening to our conversation go for good, unbiased advice on improving their diet and understanding more about the connection between your microbiome and your mental health? That's a great question, because you're right. This is an area where there's many opinions and many theories. And many of those theories and such could pan out, but we just don't know. So, you know, a conversation with a registered dietician can often be helpful. You could ask your doctor, although most doctors probably aren't thinking about this, but they might be able to direct you to a dietician who would be able to.

The other thing is just, you know, your reputable sources. There's so many articles coming out in, you know, in good publications about this. So like reading up from those reputable sources. There's so many articles coming out in good publications about this. So reading up from those reputable sources is probably also a good option. How about you? Where do you go for the latest information? Oh, well, I usually tell people that PubMed is my favorite place on the internet. So PubMed is kind of the Google of medical research. You can type in anything you want and it shows you all of the latest research that has been published in that area. So that's usually where I go. Although I will say that

the stuff being published, it's very dense. It's very scientific. You have to have some time and want to dig deep and read intensively, but you can often access the abstracts even without getting the whole article. So, you know So you could try PubMed. That's what I do. And you started to talk about some of the research that you're looking forward to, for instance, on refined sugars and mood in the years to come. What other research on this gut-brain connection do you think is needed? Yeah, absolutely. So as we were saying a moment ago, randomized controlled trials, testing the effects of sugar on anxiety so that I can more, you know, confidently make this recommendation to my patients, I think is the most important next

step of research. But the other thing that we're always trying to understand is how do we take this knowledge and how do we help empower people to actually use it? How do we translate it to people? Where is the best place to give people this information? What other information do they need in order to incorporate it into their lives? All that translational stuff, that's probably the next piece because we basically have the basics sorted out, right? Even when you look at it, it's a modified Mediterranean diet, which basically looks like Canada's food guide. And I can tell you in 500 BC, Plato talked about nutrition and it was the same thing.

So the rules of healthy eating have never really changed. But what we need to better understand is how do we motivate people to eat in this manner? How do we make it feasible for them? How do we make it interesting for them? I think that probably is the challenge that more research maybe could help us with. That is a subject for some very, very useful and applicable research. Dr. Mary Skow, thank you so much for enlightening us on the gut-brain connection and mental health. Thank you so much for having me. It was fun.

Dr. Mary Skow is a family physician with a PhD in nutrition. She recently completed her residency at Women's College Hospital at the University of Toronto. Here's her dose of smart advice. Your emotional state is a lot more dependent on what's going on inside your gastrointestinal tract, or gut, than you might have realized. Turns out that your gut and your brain are in constant communication with one another. gut and your brain are in constant communication with one another. More specifically, it's the microbiome, a half pound or so of bacteria and other microorganisms that live inside your GI tract that send signals to your brain that influence your emotional state for better and for worse. Simply put, there are bacteria that promote more calm and greater happiness, just as there are

bacteria that do the opposite. Recent studies have shown that a Mediterranean diet, one that is rich in fatty fish and other healthy fats, fruits, vegetables, nuts, seeds, whole grains, and legumes, can boost the mood of people with moderate depression. These foods increase good bacteria, which sends good signals to the immune system and, in turn, to the brain. In some of these studies, some of the improvement in depression could be chalked up to other healthy habits such as getting more exercise and more fresh air.

But there's a definite upside to your mood just by eating a healthier diet. One particular type of food that can make the biggest difference is dietary fiber. It's a general rule in our society that most of us struggle to consume the recommended amount of daily fiber. It's well worth making a conscious effort to sneak some extra lentils, broccoli, berries, avocados, whole grains, apples, and dried fruits into your diet. There's also some evidence that probiotics can improve mood by boosting the good bacteria in your gut. If you have topics you'd like discussed or questions answered, our email address is thedoseatcbc.ca. If you liked this episode, please give us a rating and review wherever you listen.

This edition of The Dose was produced by Isabel Gallant. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose. That was an episode of The Dose. You can listen to more episodes right now in the podcast feed. For more CBC podcasts, go to cbc.ca slash podcasts.