Episode VI: Our Microbial New Friends with Martin Breed

(upbeat music) - You're listening to Garden Futurist. I'm Sarah Beck. I'm here with Adrian St. Clair. Hi, Adrian. - Hi, Sarah. - I'm so excited about today's topic because we're talking about an area of science that we know is really on the cutting edge. And a few years from now or even a decade from now, we are gonna look back and think that what we knew today was just so limited. Would you agree with that? - I do. So today we're talking about the microbiome. And Dr. Martin Breed is our guest. He helps us imagine the microscopic. The microbiome inhabits the soil, the air, and ultimately breaks down into our personal space to connect our bodies to everything around us. Let's listen to my conversation with Martin Breed, a lecture in biology at Flinders University, which is an Adelaide South Australia. (upbeat music) Welcome, Martin Breed. I'm so glad you're here with us today. - I thanks very much for the invitation, Sarah. - I'd like to start with a quote from journalist Wilson De Silva, writing in Australian Geographic in 2019, describing your and others research. Every time you enter wild spaces, replete with biodiversity and breathe the air, microbes wafting through the ecosystem land on your skin, enter your lungs and gut and become part of you. They join the many billions already living in your microbiome, the community of symbiotic microorganisms inside each human being. The latest surprise is the discovery by researchers in the Adelaide that the more diverse the microbes living in the soils around us and the more you are exposed to them, the healthier you become. It's a discovery that could change our cities, make us healthier on a global scale. Wow, I was really wowed by this quote. I have to say, Martin, you've been doing fascinating research on ecology that connects humans, microbiota and the natural world. Can you start by explaining what microbiota are? And am I supposed to say are or is? So to describe what microbiota are, we need to think quite imaginatively because we can't see most microbiota. And it's the collection of bacteria, fungi, viruses, process, all sorts of things that live everywhere. And there's a famous quote and that is, everything is everywhere. And that basically describes that these microbes are on every surface and every environment that we expose ourselves to. So microbiota, that's the collection, the community of microbes in a given environment. And it's a collective word. So really it should be is, I think, but people use it interchangeably with R as well. So we can see what comes naturally to us as we go forward in that conversation. Sounds good. I also saw the term old friends. I'm curious if you can explain how that's being used and how do humans interact with old friends? Yeah, so these microbial old friends are part of our, as humans, our evolutionary history. People evolved in wild, natural environments. And today we've removed ourselves from much of that wilderness, right? So I'm sitting in my office in my house. Wherever I'm surrounded by bricks and windows and things like that, and not in a hunter-gatherer lifestyle. And these microbial old friends, it's a term that was coined by an immunologist from UK called Graham Rook. And he talks about our ancient history, our evolutionary history, where we've co-evolved with these microbes. So these are co-evolved microbiota that support us. And are intimately linked with our health, well-being, function, development, et cetera, as individuals. And we get them from our environment. So maybe you could talk a little bit more about that, because I know you've found that microbial diversity is in these biodiverse natural environments. Yet you've found less in other places, disturbed or degraded places. Where are you most likely to find these and where are you least likely to find the old friend microbiota? Yeah, and so I think the most important thing off the bat is to describe the tremendous diversity of microbes. So if you get a small sample of soil, guts, anything, there will probably be thousands and thousands of different microbial tax or all species. So where do you find this microbial old friends? Well, it's probably in areas where we evolved from. So these natural environments where we're exposed to a tremendous diversity of environments. So it's probably not going to be the very hygienic or ultra-clean environments. And that can include places in my house. And mine. Yeah, because it's good for us. I'm going to introduce a little bit of balance in a tick because not all exposure to microbial diversity is good. So there are all sorts of environments where these microbial old friends probably are not. And without giving a very prescriptive list exactly where they are, because that's probably impossible. It's probably areas that's got soil. That's probably more wilderness or more natural than those vacant lots in downtown areas. And areas that is free from contamination, which might be metal contamination or high levels of pollution, because we know that's not good for us. So there's some general rules of thumb. And one of the studies that we published was based on soil that was from a nice conservation park in the Adelaide Hills. And we compared that and showed that had health benefits to my mental health benefits in a mouse model compared to soil from one of these more degraded ecosystem areas. I'd like to hear a little more about this mouse story in just a minute. But first, I'm curious, because you mentioned that microbial diversity could help the immune system. And I'm wondering if you could explain in terms I might understand, how might they actually do this? Yeah, and it's pretty complicated. Although I guess all of us have become budding immunologists now in the COVID era, we hear a lot about vaccines and how that interacts with our immune system. And I'm not an immunologist. So I guess by default, I'm not going to talk about the technical details. But I think probably the most important thing to recognize immediately is if you count all the cells in our body, most of them are not human cells. Most of them are actually microbial cells. And what that means is we are hosting a great richness and diversity of these microbes. And they're not sitting dormant within us. They're actually functioning. So they're producing compounds. They're metabolizing. They're exchanging information, essentially, with our body. And so how do they interact with the immune system? Well, there's probably three main pathways so they talk directly to our protective immune system. So they're a protective commensal species of bacteria that we host. They also interact with what's called immune signaling. So our immune system is essentially getting trained by these environmental microbes. And that is in the form of two different kinds of immune system, immune signaling and immune memory. And they're sort of technical terms. So the way that I'd like to describe it is essentially if we live in a bubble and not get exposed to these environmental microbes, our immune system gets bored. And it is not well educated into what is friend and foe or what is self and non-self. And so this exposure to environmental microbes helps train our immune system to be ready to know what is friend foe, self, non-self. And so those are some of the disorders that people have linked with adequate levels of exposure to microbial diversity. Those that relate to allergies or autoimmune disorders. So these are the types of disorders that people have gotten very interested in trying to help understand through the microbial or friends hypothesis. Or there's another term which is the biodiversity hypothesis, which I could describe it. Basically, it's a similar idea of getting exposed to a biodiverse suite of microorganisms. And that helps train our immune system. - Well, we're certainly not hurting ourselves by spending time with soil and gardening. It's sounding like that's pretty much always gonna be a good thing. - It is, and maybe just on that, if I can add a little bit there. So I'm not an avid garden, but I garden every weekend we're out probably pulling weeds at the moment in Australia as winter. But there's this interesting discussion about wearing gloves or not. And a lot of people really like wearing gardening gloves because they believe it protects them from the bad stuff that's in soil. And obviously, if you've got cuts and abrasions, maybe that's a good thing. But my understanding is it's typically quite good for us to get exposed to that soil because most of the microbes are not going to be pathogens. Most of them are going to be neutral to us. And there might actually be some good gloves. And so obviously, if you've got very delicate hands, where gloves would be my recommendation, but there's nothing wrong with gardening with our gloves on, especially when you're interacting with soils. - Oh, I love this. This is a debate that my own spouse and I have (laughs) 'cause I have never worn gloves for any reason, but I'm sure my hands are quite rough because of it. (laughs) - But you might be healthier as well accordingly. - See, I'm boosting my immune system That is really cool. I am doing it. So let's go back to the mice, because you're also talking about evidence of mental health benefits. And I'm really curious about these mice that you were having all blissed out and happier. Maybe they weren't happy at all. I don't know. Sure. So as a research academic, you need to work on an evidence base of the hypotheses that you put forth. So why is it that people or animals that are exposed to bite-of-ers environments, or the bite-of-ers microbiota in those environments, healthier? So there's all sorts of correlations that have been published, the epidemiological evidence behind it. And so we ran a controlled mouse study a couple of years ago, which is one of the high-bar evidence levels that can be used in this context. And what we did was we exposed mice to this sort of wilderness soil, but also mice that were exposed to the degraded ecosystem soil, and also mice that were exposed to no soil whatsoever. And across about a two-month period, we had these mice in closures in the university facilities, and tracked their gut microbiota. And at the end of the trial, we assessed essentially their anxiety-like behaviour and the standardized test for that. And you then have a measure of how anxious some else is, and also what its gut microbiota composition is. And we associated one with the other, and found overwhelmingly that the mice that were exposed to a higher level bite-of-ers soil had lower rates of anxiety-like behaviour. How can you tell when the mice are not experiencing anxiety? I'm just curious what those behaviors are if they're looking super relaxed. Or if you've got a heart monitor on them. Wouldn't it be great to be able to ask them? And I guess that's the important piece of evidence that we couldn't gather. So we used a standardized test where we put mice basically in what's called a naive environment, or in essentially it's a square box, and you video track them. How much time do the mice spend around the edges, as though they were relatively scared, compared to spending time in the middle of the maze. And that's been linked with other studies to do with the things that you described, not the interview, but things like heart rates of mice and other indicators of stress, so stress hormone levels in the mice, which allowed us to have confidence that what we were measuring was closely linked to this anxiety-like behaviour in the mice. But maybe now's a good time also to say that this is at the forefront of this area of science, and we're not the only group that's doing this work. And the group in Finland has done what we were hoping to do, and we probably still will do down the track. And that is do something with people, because there's all sorts of differences between us and mice, right? Even though it's one of the most important pillots to the medical research community. So they, in a study that was published at the end of last year, they introduced basically forest materials into daycare centres. And without going into all the details, it's an amazing study. They found essentially the same thing. So rather than anxiety of children in these daycare centres, they looked at immune system changes in the children and their gut microbiota and observed those children that were exposed to traditional daycare centres that had this, what they called a biodiversity intervention. So they brought branches and dirt and moss from the forests of Finland into the daycare centres. Those children had these similar benefits. So nature play and forest bathing, I mean, clearly work for everyone. It absolutely does. And although the most, I think one of the really important parts here is it's not just going out into these wilderness areas and forest bathing, which maybe for many of us, that's not possible. You can bring this stuff into a daycare centre, right? So this is not a special daycare centre, the way that was described in the study. This is any old daycare centre. And maybe they are quite different in Finland, but still that, I think, break down some of those social equity barriers, which we could talk about in a luxury effect. Yes, yes, yes. Absolutely. So that, I think, was very positive with their results from this study. Oh, that makes me want to take all kinds of bundles of forest material to all the daycare centres everywhere urban. Oh my gosh. You're listening to Garden Futurist. We'll be right back. Hi, Richard Hayden here, and I'm honored to serve as the chair of the Pacific Corticulture Board of Directors. When I was young, I was fortunate to be surrounded by garden mentors that introduced me to the magic of plants in the natural world. Won't you help me pass along that passion to the next generation of garden enthusiasts? Garden Futurist is just one of the many programs that Pacific Corticulture is creating to inform gardeners young and old with the most up-to-date scientific information on gardening in the Pacific region. Support us, become a member today. Visit pacificcorticulture.org. Thank you. Let's jump to this. You say that there's unhelpful pathogens more present in degraded environments, so we know ecosystems can be restored. I'm curious if you're finding that microbial diversity can come back to some of these places that were degraded. We were just talking about cities that might not have all these wonderful old friends there. Can the cities eventually be good for our health if we can figure out how to bring all of our nature objects in? Yeah, that's a really important question because really, as a research academic, I guess I could if I wanted to stop at the end of understanding causal links and then walk away and say, "Oh, it's somebody else's problem to go deal with how we implement it." But in this day and age, or at least that's, I'm not driven by that. I want to make sure that this kind of work is implementable. So, as a restoration ecologist, we're working on absolute, we're working on ways to fast track the recovery of microbial communities in soils that then people could hopefully roll out in relatively small areas, in cities, in those period urban areas, maybe even backyards. It's more difficult in backyards, but the kind of evidence we're building there is both correlational, but also doing intervention studies, so understanding how we can, let's say, if you plant a biodiversity vegetation community, how long would it take before the microbial community catches up, or is the microbial community even leading some of the plants to get to this latter-stage, successful state? And so, the best available evidence would suggest it takes. We're aiming more than 10 years, it might be actually, it's actually longer than that, depending on the extent of ecosystem degradation, and we're working a lot in that space because it's difficult to directly manipulate the soil microbiota. So, if we just focus on plants, we're probably looking at several years before we get a significant ecosystem shift in the soil microbiota. So, there's the second avenue, which is in areas which might be more priority areas, let's say it is our backyards where we can invest our own money, or in areas that are designated as healthy parks. And so, these sorts of areas, I think, need to get. Probably more investment per area than the broader areas, and in those areas you can do what's called a soil inoculation, which is essentially taking soil from one place, mixing it with the place that you want to try and rehabilitate, and then sowing those seeds as microbial seeds and allowing that ecosystem to flourish. We know that in ecosystems that are relatively degraded, they're also linked with the presence of known groups of microbes of pathogens in them, and those ecosystems that are relatively healthy, or with good ecosystem functions and a great diversity of plants and probably animals as well, they tend to have more of this microbial on friends. And so, you can use ecosystem restoration to help transition an ecosystem from a degraded state to a restored state or a recovery state, and that does take a long time, although there should be ways, and we're working on some of these when I can't go into all the details, because it's not yet published, and we haven't got the results yet for many of these, but there are ways that you can fast track that, and there's a common phrase that's used in this space, and that is the soil remembers. And what that means, it's both an opportunity, but also a significant challenge. So if an area has been a carpark for 50 years and you all of a sudden want to create a functional and biodiversity environment, that's going to be quite difficult, because the soil in this carpark is going to remember those 50 years, that it was a carpark. But also then if you do transition a soil environment to a functional ecosystem, it also has the ability to resist change as well. So if you can work with these plant soil systems, invest time and effort in understanding what the key biotic or abiotic barriers are to achieving that restoration. I'm probably an optimist anyway, but I am very optimistic that there will be ways to fast track that recovery of health promoting soil microbiota in our cities. This is very exciting. And in just a minute, I want to get to more of how being a gardener and working with soil and plants is going to possibly come into this future scenario. I also want to ask you though, you mentioned the arrow biome, which you know, I know during COVID we talked about aerosol science all the time, and you know, you mentioned that these small particles might just be in the room with you. How does this arrow biome concept work, and is this having to do with this public health urban planning conversation? You know, it's not just Placing a big garden bed somewhere, right? Absolutely. And I think one of the most important things that didn't come up before in our conversation is we don't eat dirt. Most of us don't eat dirt. So if you develop a soil biological community that's full of these microbial odd friends and we're not exposed to it or we don't interact with it, then well the health gain has not been realized. So what's the pathway of getting exposed to that? And how does that relate to the green spaces that we have in our cities? So that's an area of research and we've been trying to crack that up because that really is a very challenging space where we need to know does the soil microbial community get aerated above the soil that we might be walking through? And we published a couple of studies in the last year or so that shows absolutely yes it does. And so the closer you are to the soil, the more soil like the aerobion is. That's perhaps intuitive but we also characterized what's called vertical stratification or we call it vertical stratification in the aerobion. So the higher off the ground you go, the more dissimilar the microbial community is. And that's a problem because if you're an adult I'm about six foot tall or so. You might be too tall to experience all these benefits. And little Ali, when he can walk, he's probably going to be at that half meter height and so he's going to be exposed to a very different community just because he's closer to the ground. And the reason why I think this is really important is because it's very hard to change people's behaviour. And when public health recommendations come out that say do not smoke or do lots of exercise, there's going to be lots of people who will not do those things. And maybe eventually people will agree to it and see the value in the behaviour change or get I guess feel the social pressure to make the change but it's very hard to change people's behaviour. And we've seen a lot of that with COVID, with all sorts of politics and social issues that are going on. We see it all the time. So as a public health person you can do things that people then get the benefits without having to change their behaviour and that's where this really links in. So can we develop an aerobion in areas that people commute on a daily basis or where people work or where people live where they don't need to change their behaviour but we've changed their environment. So can we transition the aerobion by creating aerobion supply parks where these microbial communities in the air spill over into the commuter areas and people can walk through and hopefully get bombarded with a safe community of microbes and get the health benefits accordingly? Let's dive into that just in terms of those of us who are garden futurists and you know the Pacific horticulture crowd maybe not immediately now but what do you see in the future as their role? What if a community garden could be one of those hubs where you could passively enjoy the benefits of that aerobion? Just you have to bend down and smell something probably right? That's right and the garden futurists I think that is essentially what we're talking about here. These are gardens multi-purpose gardens we need to work with people who know how to make aesthetically pleasing gardens because people then will be more attracted to go to them and spend time in them hopefully. We also need to make them sustainable where in Australia probably like some parts you know Western US in California and such there's limited amounts of water so we need to make them fit for purpose as well but I'd love there to be ways as a community of people that goes around and knows one of the benefits of developing these gardens that people want to go to is to their health but at a level of let's say a city or across a region there's a second problem and that is areas that are relatively poor tend to have less biodiversity and are likely to benefit more from this. This is called the luxury effect. Calling for ambassadors I think is a very important component here and we can't just develop really what I would call a luxury commodity. We want this to be used and the benefits are real in the areas that are relatively poor or the communities that are relatively poor off and so I think there's a responsibility to ensure that it's not just helping improve the wealthy areas but also works in other areas where people may not have the time, the spare time and the ability to do this kind of work so yeah that's where the ambassador role I think comes into it absolutely. I love this idea of this being somewhat of a civic experience too I mean thinking about city spaces I'm curious if you think in the future there will be some set of recommendations that could align in terms of plant species decision-making as well and whether some of that comes into play as far as our selection of plants and that relationship to the soil. Absolutely and that's one of the most common questions I would get asked around here and that is if we know that we can create these sort of a soil environments what do I plant and that's a difficult question because people just haven't done enough studies in this space so I would think a lot about the diversity of plants because diversity of plants creates diversity of habitats for microbes and that then hopefully and there is a hope there is an association. I would hope that also creates then that health provision from the soil microbial community. So the work that Pacific Horticulture is is doing right now trying to encourage as many people as possible to grow biodiverse and climate-appropriate and water-efficient plants and we're basically already improving the immune health of everyone around us by doing that. We may not know exactly what the percentage mixture is if we should you know have a certain number of grasses and trees and fruiting things or what that should be but it sounds like you're saying we're we're not going to go wrong on that track. I think that is absolutely right so it's a a very low risk recommendation. It's probably good for us but it's definitely good for nature and it's definitely good for our local ecosystems so we're and not just me and my team but there's many teams really trying to work on those causal relationships and I'd say we have a conversation in a couple of years time we might know a lot more about that jigsaw puzzle which is what species where to create this certain health outcome because people are really running with that around the world and two to five years I think there's going to be a lot more known about that jigsaw puzzle because at the moment I completely agree there's an extremely low risk pursuit to do this biodiversity versus orientated gardening and it's probably got immune benefits via a gut microbiota and other pathways the microbiota is only one pathway. Yeah now I'd be fascinated to understand whether some of these you know the habitat gardening that we're working on doing with a lot of pollinator focus thinking about those relationships between plant and animal interactions and then the soil I mean there may be all kinds of special interconnectivity there right absolutely so talking about pollinator gardens or habitat gardens I mentioned before everything is everywhere in a microbial world but there's a second part of that sentence which is but the environment filters and that's an ecological term where everything could be anywhere but things get selected for and again and so we need these pollinators we need these animals in the ecosystem and these you know we need wind and everything else because this is helping to move and distribute these microbial communities so we need these to think of a better word we need these vectors to move these microbial communities around so we create a really rich biodiverse soil environment in one area full of microbial old friends and it to sit there that's probably not very good but we need ways to move it around and so creating I think is habitat gardens there's a very very good way to help move that benefit into other areas I think it's a wonderful opportunity to really bring nature into our cities into our backyards into our school systems which you know a lot of them are gray spaces and so I think it's a very optimistic vision to actually introduce some biodiversity into everybody's life not just the garden enthusiasts but they can lead it yeah absolutely and we can bring human health as well as environmental health thank you so much for your time today this was really fun it really was thanks so much Sarah that was a really interesting conversation Adrian what do you think this was fascinating it's something that I've been interested in for a really long time and I've come to embrace this idea of the microbiome being this safe and beneficial thing for us but I have to tell you that having a kid in the pandemic has really challenged that idea for me and so it's great to hear and be reminded of and it really encourages me to get her outside as much as possible in the time that we have and that was such a I think fascinating part of that conversation especially knowing that Dr. Breed has a very small person at home right now himself and thinking about just some of the issues of equity and thinking about how those of us who are city dwelling or really anywhere where there are degraded environments we may not have access to the microbiome that it would be present [BLANK_AUDIO] in a beautifully restored or even a landscape that is fairly untouched. So thinking in terms of equity, it just really made me reflect on this thought that obviously we want everyone to be able to interact with this immune boosting and harmonious world and to have that obviously all wanting to have the arrow biome around us to be safe and but also beneficial. - Yeah, yeah, the point that he made about being able to bring in parts of the forest into daycare centers and into schools and that that could help break some of that barrier of equity and people having access to nature, I thought was very compelling. I'd like to see that grant be written. And this tiered layers of arrow biome coming up from the soil and how he met six feet versus his child, that you know, a meter, three feet, that difference in the arrow biome was fascinating. - Oh, I thought that was incredibly interesting that there are these strata of experiences to be had out in the world depending on how high up you are. - It gave me this visual of like when we talk about forest bathing, we should actually be talking about being on the ground in the Duff doing dust angels. (laughing) - Forest crawling, what we need to be doing. - Yeah, we might be too high up. We need to get down where the children are. - Yeah, more playtime, grownups need more playtime. - Oh, that's fantastic. - The other thing that just occurred to me is just this conversation that he sparked about the idea of designing how to design city spaces, not necessarily just city, but how communal, how civic space might in the future look based on our knowledge of some of these points. And this idea of just looking at where people are passing through, let's say people are going on their way to public transportation or through a city park or any of these communal spaces. If we have that understanding of the microbiome and the arrow biome, how would we perhaps fill some of those corners and those spaces that are just part of our everyday civic experience so that they're benefiting us in some way? - What I think it was most exciting about what he's talking about is that we all have a path to the microbiome. So we've got our backyards and we've got the plants that we're planting in our backyard in the soil that we're working with or we've got our community gardens or we've got the local park or the regional park or we can drive off into wild and urban, wild settings. And so whatever that path is for you seems like a great option. There's always some more microbiome to be included that isn't in your own home. - Yeah, I love that. And it just creates this feeling of access and the more that we can be aware of the microbiome as we think about all of these aspects of life, whether it's as large scale as designing a civic space or spaces that humans move through in a city or a town or if it's just about our awareness in our own spaces and our own gardens that this opportunity to touch soil and not wear our gloves and allow ourselves to interact with ideally healthy soil, healthy plants and plants that are adapted and appropriate to that place. It's likely those benefits will be available. - Thanks to everyone for listening today. If you liked Garden Futurist and would like to hear more episodes or want more Climate Resilient Gardening techniques, find us at PacificHorticulture.org. - Virakino is a not too big, not too small, Santa Cruz-based winery. Virakino produces minimal intervention, maximal pleasure inducing wines from a wide array of responsibly farmed vineyards, including many planted between the late 19th century and the early disco era. We strive to produce wines which defy rather than exert gravity, which revitalize and revive and which authentically express the character of the sites from which they derive. Go to Virakino.com and enter the code pH at checkout to receive a special 10% discount. [BLANK_AUDIO]