The fungi scientist: The #1 mistake you're making when eating mushrooms for health

Oyster mushrooms make about 100 times more vitamin D than your routine field mushroom and we need relatively good levels of vitamin D particularly for our immune system. But the big thing is they are making vitamin D just like us in response to sunlight but most mushrooms grow in the dark so actually laying out your mushrooms in a bit of sunshine is enough to raise the level of vitamin D very dramatically. However the way you prepare your mushroom does have an impact on what stays in the mushroom. So what should I be doing? Robin May is a world-leading expert on fungi and their interactions with the immune system. He's published hundreds of papers and is a professor of infectious diseases at the University of Birmingham and Acting Chief Scientific Advisor to the UK Government's Food Standards Agency. Mushrooms are really important for influencing the microbiome of the gut and of course the good microbiome can have a very strong positive Are there any funguses growing in my gut? Yes and historically people said fungi growing in your gut bad thing. However it's really only in recent years that we've started to understand a bit more about some species that are quite good to have in your gut helping to keep our immune system in balance. One of the big things I hear is about brain aging. Any evidence around this? Some extracts of lion's mane fungus protect your brain. It stimulates nerve growth demonstrating improvements in cognitive decline. If someone's listening to this and saying I want to add more mushrooms to my diet what would be your one tip? Can I do a tip and an anti-tip? Yeah you do it. So my anti-tip is... Are mushrooms more closely related to humans than to plants? Yes. Does some mushrooms contain vitamin D? Yes. And finally what's the biggest myth that you often hear about mushrooms? I think it's the weirder the mushroom the better it is for you. Caution against that one. Not true? No stick to the mainstream I'd say. Is that only because you might die by eating the weird mushroom? There's quite a lot of risky weird mushrooms out there so yeah if someone's selling you something in a brown packet I would be cautious. One of the things that I've learned running a data-driven health company is this. Small actions create compounding impact and your hitting subscribe is one of those small actions. It tells the algorithm that this show matters and that helps us to reach more people then lets us bring you more science-backed advice. So if this episode gave you value subscribing is how you can give a little back and we'll keep showing up every week to return the favor. Okay back to the show. When I was young mushrooms were definitely something I ate but only because my mum liked the taste of mushrooms when she was cooking and then more recently I feel like I'm surrounded by claims that mushrooms can extend your life, like improve your immune system, prevent brain aging and so on. I love the taste of mushrooms so any excuse to eat mushroom is good but my son hates them so it's not really the taste like the texture. So my objective for this podcast is to come out with compelling arguments for why he should keep eating mushrooms even though he doesn't like them very much. Right okay mission in mind yeah I can't change the sliminess I think but bad luck. You had this crazy answer that a mushroom is more closely related to me than it is to a plant. So what is a mushroom? So we now know pretty clearly that mushrooms and animals share a more recent common ancestor than plants do so if you think about that evolutionary tree of life plants branched off earlier than fungi generally and animals did so hence the answer we're more closely related to a mushroom than to a plant. Not by much I have to say that branching is still a very long time ago but actually that explains quite a lot of things I think about mushrooms so if you think the most obvious thing is they're not green right they don't photosynthesize plants do so that tells you already that they're probably not a plant. If you look sort of molecularly there are quite a lot of other reasons why they are more similar to animals so for example some of the machinery that we use to make proteins in our cells fungi use machinery that's more similar to ours than the machinery plants make so there's quite a lot of reasons to be confident that we are more closely related to fungi. And so you just started to touch on it but are there other differences between fungi and plants and so does that mean that somehow if I was eating a mushroom there are therefore genuinely going to be things that I'm sort of eating that wouldn't be in a plant? Yeah absolutely yeah so perhaps the most obvious is that plants and fungi both have cell walls which is why they're rigid unlike animal cells we're pretty floppy but it's made something completely different so so plants are made of cellulose people might remember that from school fungal cell walls are made of a molecule called chitin which is actually the same molecule that is in the shell of crustaceans so lobsters or crabs or insects that the crunchy bit if you step on a beast that goes crunch that is chitin it's the same molecule in a fungal cell wall so that's a that's a really obvious one and then if you kind of really look biochemically I mean one of the most amazing things about fungi is they are incredibly chemically diverse and so for instance many of the antibiotics we get today are produced by fungi because they are able to do this fantastic chemistry in some cases chemistry that we haven't managed to crack as humans yet so there are depending on the species lots of molecules you find in fungi that are not found in in plants or in animals or sometimes even in other species sometimes really unique. And so that means that if I was eating a mushroom there could genuinely be like molecules in there that I just would never get even from eating lots of diverse plants? Yeah absolutely and they can be good bad or indifferent so there are some nutrients that come from mushrooms that are really important but of course people are familiar with the fact that some mushrooms some toadstools are hugely poisonous potentially lethal and of course there are also magic mushrooms that produce hallucinogenic compounds that are not found in other species. Now I asked about mushrooms and you immediately switched out to fungi I ran with it but can you help me to understand what the difference is? Yeah absolutely so we talk about the fungal kingdom so if you think about we talk about plants and animals and fungi so each of those is a kingdom it's a big group and fungi as a kingdom we don't really know how big that is we estimate probably something like one and a half million species of which the vast majority are still not known to science. They're all closely related in the sense that they all share those characteristics like a chitin cell wall but they are wildly different so for instance athlete's foot on your foot is a fungus the yeast that you put in to make your bread rise or your beer brew is a fungus the mushroom you buy in your supermarket is also a fungus so fungus is the wider group. Mushroom sort of doesn't really have a kind of biologically defined term but we tend to use it for the fruiting body so if you think about what a mushroom looks like in a supermarket if you see that growing in the field that's actually a tiny fraction of the whole organism most of that organism is invisible underground in this kind of hair-like network that's called a and it's only when it fruits that comes up so I guess it's a little bit like thinking about you know we talk about an apple but the apple tree is you know much bigger than the apple alone so the mushroom is the fruiting body of a particular species and not all fungi produce mushrooms so the yeast that you make bread with you know you don't come hopefully don't come down in the morning and find mushrooms popping out of your bread certainly not from that yeast anyway it stays as a yeast its whole life. Other fungal species can move between this yeast form and this fruiting form. Actually the kind of scale of the invisible part of fungi is something people often overlook so if you think about out in your garden or the woods you see a toadstool pop up often that toadstool is revealing the presence of a mycenae that's enormous and in fact there's quite well documented cases in the United States for example of individual fungi that stretch for miles underground so you see a mushroom pop up here and five miles down the road you see another mushroom pop up and it's actually fruiting bodies of the same super organism that's under your soil but we just can't see that bit. That's wild so you're saying there is just one fungi that can be like five miles long? Yeah biologists like to fight over kind of records and if you're a kind of mycologist or someone who specializes in fungi you always claim that you have the biggest organism in the world because if you were able to haul that out of the ground it would be far larger than a blue whale or a giant redwood obviously the problem is we can't actually extract it and show that. Now I think all our American listeners would say yeah but of course everything's bigger in America so is it just in America that you get five mile fungi or if you were in Europe or Australia whatever I mean is that also true? Yeah I feel like we might be starting some kind of international competition here for large fungi no so the largest one that we currently know of is in the United States I don't think there's any reason to believe it would have to be in the United States I suspect quite a lot of this is about who's going looking you know there are lots of really great mycologists in the US who look at these things but I'd wager you can find a bigger one in Brazil if you go When I was young like I only ever saw button mushrooms in the store and now I regularly see like oyster mushrooms and shiitake and lion's mane and that obviously represents the fact that many more people are eating mushrooms and also like this sort of wilder diversity what's been driving that shift in terms of just like what we're able to eat in the supermarket? Yeah I think there's probably a couple of things that are playing there so I mean obviously here in Europe and the US we've been very restricted in our palates for quite a long time I mean that's not true in the Far East for example I well remember many years ago traveling to Japan you know and having just extraordinary dishes with mushrooms which I had never seen before and which people couldn't tell me the name of so I think many cultures have a much more diverse repertoire already part of that change in Europe and the US in recent years has been that globalization of the food economy people traveling eating stuff they like elsewhere and saying why can't I buy it here? Partly it's also about the ability to produce these so producing mushrooms or related fungi is quite different to other sorts of farming and so it takes investment it takes kind of skill and so you have to sort of have a market that's going to make it worthwhile but of course as we know the more exotic fungi mushrooms often sell for quite a premium and so there's been quite a big market driver to support the development of those and I think probably the last thing is that people have become sort of more experimental in their diets people are very interested in healthier diets more diverse diets cuisines from elsewhere and so I think it's driving that overall kind of shift in in what we buy and what we cook. I'm struck by you're saying that when you first went to Japan you suddenly saw that they ate all of these different mushrooms and you're an you're like oh I don't even know what this mushroom is is that because there just were many more varieties of mushrooms that you can eat or is this just because somehow western Europe and obviously you know places like America just were not really open-minded about it? Yeah I think it's probably a bit of both I think I mean so one of the characteristics of most fungi I like growing kind of damp humid conditions I think there's something about the climate you're in so if you take the UK for example you know middle of winter you can't go and find mushrooms out in the wild because it's too cold and there's just not enough environment for them if you're in the tropics you can find mushrooms toadstools all year round so there's something about availability historically but I think there's also something about sort of cultural acceptability and particularly the kind of flavours a lot of fungal species that we eat especially the more unusual ones have really quite marked flavours and we know that people are usually quite reluctant to kind of experience new flavours initially and they have to kind of be exposed to it and so one of the things for example is that many fungal species have a very strong umami flavour this sort of quite difficult to describe is this kind of rich kind of deep flavour that polarises people I think that's a much more common flavour historically in Asian cuisine for example and so people are ready to embrace this I suspect in 1950s England if you'd have come with a strong umami flavour people might I'd love to now sort of almost drill down to nutritionally speaking sort of what's in a mushroom well it depends quite first of all on what we mean by mushroom I think I mean clearly the one we know the best is the classical mushroom that you buy from you know the supermarkets white or brown big cap on the top it's an agaricus species and we know quite a lot about that mushrooms are often used to replace meat in sort of vegetarian type cuisine and it's a good replacement so they have more fibre definitely than animal products not as much as some of the kind of really fibrous sort of whole grain food I wouldn't recommend substituting your granary bread or your oatmeal with fungi but they're quite healthy in terms of fibre good levels of protein very low levels of fat particularly saturated fat so that's already promising but the thing that gets people quite broadly excited I think about mushrooms is a lot of the more interesting kind of trace elements and vitamins so if you think about the way that fungi grow we talked earlier about this kind of mycelium network in the soil so they are scavengers essentially they're harvesting nutrients from the soil from decaying matter so they are really good at accumulating things that are quite rare or trace elements in nature so for instance things like potassium they accumulate very well from soil relatively rare compounds like selenium are also quite often accumulated by mushrooms and then last of all they're pretty good at making vitamins say they make vitamin B, vitamin C and the one that gets people really excited is vitamin D because vitamin D is extremely rare in plant species and we need relatively good levels of vitamin D particularly for our immune systems and so people often talk about mushrooms being a great source of vitamin D although it is slightly more complicated than that. I asked at the beginning is it true that mushrooms contain vitamin D and I think we often think about that as something you get by being in the sun what is the reality? Yeah so you're right so we make it by being in the sun and just as a kind of caveat here that does not mean going out and getting yourself lobster pink that's a very bad thing to do you don't actually need very much sunshine even in rainy old Britain but you do need a bit of sunshine to make vitamin D. Dietarily we get it from a variety of foods but many foods do not have vitamin D and actually mushrooms are a great source in the winter in particular it's quite difficult for people in northerly climes like the UK or northern US to make enough vitamin D so that diet becomes really important and mushrooms are often touted as a great way to get vitamin D because they make vitamin D sometimes to very high levels. There are two caveats there though the first is that the amount of vitamin D they make is very very variable between species so for instance if you think about oyster mushrooms which you can now buy in most supermarkets they actually on average make about a hundred times more vitamin D than your routine field mushroom that might be next to it in the shelf so there's quite a big variety between mushrooms. And Robin when you say routine field mushroom this is like what I think of like a little cat but it doesn't matter whether it's white or brown. Yeah button mushrooms, field mushrooms, the kind you might have on your English breakfast or mushrooms on toast or whatever that one so they do produce vitamin D but they produce less. And so you said oyster mushrooms create a hundred times more vitamin D than like the typical mushroom that I grew up with and that I thought was the only mushroom probably when I was 15. Pretty much yeah exactly and that's very you know different species make more or less but the big thing about all mushrooms pretty much is they are making vitamin D just like us in response to sunlight or actually in response to UV light so if you have and of course if you if you think about the way mushrooms grow they shouldn't see very much UV because most mushrooms grow in the dark so if you grow your mushrooms in a industrial farm in the dark, harvest, stick them on a supermarket shelf and someone comes five minutes later and buys them they'll have almost no vitamin D in them because they won't have seen much sunshine. But the longer they see UV light for the more vitamin D they make and so you might be able to you know you might have seen in shops vitamin D enriched mushrooms which are essentially mushrooms that have been left in the sunshine for a little bit of time. You can do the same trick actually at home because they will produce that reaction to create vitamin D is a spontaneous chemical reaction so what's happening is a molecule in the membrane of the fungus called agosterol is being converted by UV into vitamin D essentially so you don't need the mushroom to be growing to make vitamin D so actually laying out your mushrooms in a bit of sunshine where it'll get UV so not inside a glass thing because glass filters out UV but outside on your picnic table or whatever they'll start producing vitamin D and actually an hour or two of sunshine is enough to raise the level of vitamin D in mushrooms very dramatically to the point at which a kind of decent serving of mushrooms eight or nine mushrooms will give you your daily requirement. I guess a bit like fruit that continues to ripen and the bananas I'm used to you're saying if I put that out in the sunshine for like literally one to two hours suddenly it creates this like rather amazing amount of vitamin D because you then said well then eat eight to nine mushrooms and I've had my daily amount and if I think about other vitamins I'm always struck that often they you know they claim it's on the pack but you have to eat an awful lot to actually get the amount that is recommended. Yeah exactly so and it's obviously there's a variable art here not least because mushrooms vary in size but you know as a very ballpark sort of estimate you know 50 to 100 grams of mushrooms that have been in the sunshine for an hour or two will give you plenty of vitamin D for a day. Now you mentioned before that different mushrooms are very different in the amount of vitamin D so is it all about the oyster mushroom now? No not necessarily so as you can imagine not that many mushrooms have been studied there was an interesting study a few years ago looking at the quantity of vitamin D in various commercial mushrooms I think the winner actually was the bolete which is a kind of slightly exotic fancy mushroom that not many people have eaten so harder to buy that one from your supermarket but if you get the chance they have I think that's 500 times as much as your typical butter northfield mushroom and then oyster mushroom and then you have you know the kind of more routine mushrooms have a bit less. I mean pretty much all mushrooms do make some vitamin D so this is you know so I wouldn't kind of run away and not eat a mushroom anymore but it's just worth bearing in mind especially if you have the opportunity you know whilst you're cooking put your mushroom pot outside for half an hour and then throw it in your omelette and you'll do yourself some good. And so are the other ones all roughly similar to the button mushroom or is it particularly bad I'm just curious. No it's not particularly bad there are yeah there were several with that those kind of levels and actually there's quite a lot of variability there so one of the things that's slightly frustrating for us scientists is the structure of the mushroom seems to make quite a difference so you have more of the molecule that turns into vitamin D in some parts of the mushroom so whether it's kind of flat or open or button makes quite a big difference generally speaking there seems to be more ergosterol and therefore more vitamin D made in the gills so in the kind of fluffy bit under the mushroom than elsewhere but I mean I wouldn't you know I wouldn't take the effort to turn all your mushrooms upside down to make it work perfectly. And for those of us living in cold northerly climates is this going to work or is this a great trick but it only really works in Florida and frankly they don't need to worry about the mushrooms because it's sunny. So you need the UV to make the conversion work but actually even winter sunshine has a reasonable amount of UVs if you think about you know one of those gloriously winter crisp days in Boston for instance you know putting your mushrooms out will be fine actually would do quite a good job there and I think the other point is that this is not your for most of us this is not your sole source of vitamin D so for example things like cow's milk also have vitamin D so if you're you know having milk on your breakfast and a mushroom you know you're still doing pretty well. So yeah I wouldn't worry too much about that I mean clearly if you live in northern Sweden and you've got 23 hours of darkness it's not going to be such a great trick for you in the winter and you might want to think about vitamin D supplements instead then. Brilliant well I'm definitely now pushing oyster mushrooms right up in my head as I'm thinking about this. While we're talking about vitamins the team who were doing the research here said that there's a compound that I have never heard of before that I have to make sure I ask you about which is called ergothionein. Very good yeah. What is that and why is it that some scientists apparently saying it should potentially be classified as a vitamin? So ergothionein is a very interesting molecule it's a natural amino acid so people might be familiar with the idea that amino acids are the building blocks of proteins we as humans make about 20 or use about 20 amino acids to build our proteins but there are other amino acids that we don't make we don't use that are used in other organisms and ergothionein is one of those. So it's made by fungi in particular and in laboratory studies it has quite potent antioxidant anti-inflammatory effects so antioxidant people might be familiar with this idea of reactive oxygen species so we're familiar with oxygen that we're breathing now there is a chemically related molecule which is a kind of charged reactive breakdown product of oxygen that damages things it damages proteins it damages DNA and it is thought the reactive oxygen account for quite a lot of cellular damage as we age in particular. It's one of the reasons for instance why you know if you spend a lot of time in sunshine you get older looking skin because the reactive oxygen that's created is damaging your cells. So reactive oxygen not great ways to mop up and dispose of reactive oxygen are therefore thought to be beneficial in protecting us from damage and helping delay aging and ergothionein is a really good molecule of mopping up oxidative damaging agents. So in a lab absolutely this soaks up reactive oxygen so that seems like something you might want in your cells and so there has been quite a big kind of interest in whether eating loads of mushrooms will give you lots of ergothionein and that will help protect you. I have to say the data on this is very much still up for debate so you know if people are listening because I wouldn't race out and order yourself massive supplements we're still a long way off being sure. What we do know is that in some situations it does seem to have some potential beneficial effects. There have been some studies looking at cellular hallmarks of aging and if you're exposed to ergothionein it seems to reduce that. No really good clinical data suggesting broader health impacts them in it but as with all science you know there's a lot more to do in this space. One of the really big mysteries I think to ergothionein is we humans have a specific protein that is used to take ergothionein into our cells. It's very conserved so other species have this too and that sort of suggests that it must do something really quite important because evolution has kept it and looked after it. However our kind of typical way of testing these things is to remove it genetically from mice for example. Those mice seem pretty fine actually so there's a bit of an enigma here we have this protein that appears to have been conserved does something important but we don't know what the important thing is and perhaps the last and most weird unexplained thing is that that version of that protein that takes up ergothionein varies between different humans so different populations have what's called polymorphisms variation of this. We don't really know what that means or why that's important but there has been quite a lot of renewed interest in that because it looks like one particular variant of this is associated and stress associated rather than causative but associated with Crohn's disease and so if you carry that particular type of ergothionein receptor you appear to be more at risk of Crohn's disease. We don't know why and it may be complete you know red herring correlation but yeah a lot of interest in ergothionein. So this is one of these examples where we're getting access to like this very early scientific insight but you're not suggesting that we all have to go out and make sure that we're getting enough ergothionein from our mushrooms and we're all going to live for another five years of healthy life. Yeah I mean it's kind of like the scientific equivalent of that moment when you've finished your flat pack furniture and you've got this thing left over and you think this looks like it's something really important but I don't know where it goes and so we're at that point I would say. Do all mushrooms have like high levels of this ergothionein or is only in particular mushrooms? So not all mushrooms use ergothionein but it is relatively widespread so it's very rare in other branches of life so plants don't make it, animals don't make it. The places it's made naturally are quite a lot of fungal species and in the cyanobacteria so these photosynthetic bacteria that are associated with things like algal blooms in the sea but obviously we don't eat those so mushrooms are your best bet. Levels vary in different mushrooms and we don't really know how they vary in different species we also don't actually know what a sensible level would be so that has neuroprotective effects you know because we don't know what it does we don't know whether such a thing is too much of it or too little. So if I was having like a standard like butter mushroom is there likely to be some ergothionein in it? Yeah there is your standard mushrooms have some levels vary and again we don't really know what a good level is so I mean no evidence of harms that's always a positive thing but I think yeah we're definitely far from saying this is some kind of magical cure-all. And so we talked about vitamin D, we talked about this ergothionein, you mentioned at the beginning that there's quite a lot of fibre in these mushrooms, are there any other nutrients that are like helpful for us that are in mushrooms? Yes so most mushrooms produce vitamin B and vitamin C and they also I think we mentioned earlier they harvest these kind of minerals like potassium and selenium and they do quite a good job of that actually so generally there's quite a lot of kind of trace elements or minerals that are in mushrooms that's good for you. I'd love to talk now about some of the health claims that surround mushrooms so less about the nutrients and more like what does it actually mean for us as human beings and I know talking to friends of mine from like China and Japan that apparently they've been like an important part of their sort of traditional medicine apparently for thousands of years but I'd really like to know what the science says. Is there any evidence that suggesting eating mushrooms is linked to either healthier lives or longer lives? Let's focus first of all on kind of your classical supermarket mushroom and the short answer is no not really so there have been a couple of studies looking at these very large population studies looking at diet and longevity. A couple of caveats one is they're usually done by what's called recall studies so people say Jonathan what did you eat last Tuesday you know and I don't know about you but often I think I don't know what I ate last Tuesday so there's a lot of patchiness in the data. As part of a broad varied diet that doesn't have too much red meat etc etc they do have a significant benefit so for example even if the mushroom on its own is not particularly dramatic if you're replacing your fillet steak with a you know mushroom then actually that will have a benefit because we know that too much red meat is bad for you so so there's a there's a thing about eating mushrooms as part of a varied diet that's good but as a kind of magical food to make you live forever unlikely I think. So is it just that the data isn't there and you think it is beneficial for health or do you think that it's like a good thing like lots of different plants are but you know even if we did a great experiment you're not going to see any impact? I think the data is a real challenge for a couple of reasons so one is that we talk about mushrooms in inverted commas but you know that's a bit like talking about plants you know and I was thinking you know does eating plants correlate with long life well yes it definitely does if you don't eat any plants you're not going to live very long so I think there's a big problem there that we talk about kind of you know mushrooms generally and we're not able to distill in to individual levels of detail. Secondly of course it's actually pretty recent I mean in some cultures people have been eating mushrooms for a long time in most western European US cultures it's it's a very small number of species for a very short period of time and those those the areas of course where most of these long studies have been done so you're so the data is not just the data is not there but the experience of people is not there to draw on that might change going forwards now that people eat more species there is the potential to really look in more detail particularly in other cultures where you know a broader diversity of fungi have been eaten for a longer period of time and maybe we'll see something interesting then. One of the big things I hear is about brain aging is there any evidence around this or any reason to think even that it might matter? Yeah one of the points about fungi is that this is a huge diverse group of organisms right one and a half million species and they are amazing chemists so they can produce just wild molecules and you know perhaps the best example is you know antibiotics right penicillin is a fungal product I mean now we make it synthetically but uh but it was a fungal product and so they can make impressive chemicals so you know at face value might mushrooms in inverted commas help us live forever absolutely because somewhere out there there might be a species making something really important. If we're thinking about kind of the small number that we eat at the moment it's part of regular diets there's been quite a lot of interest in whether particular species might help protect your brain and lion's mane is the one that's often quoted as a kind of you know lion's mane fungus live forever and there is a little bit of data suggesting that that it's worth at least looking at this in more detail so for example some extracts of lion's mane and actually some other species seem to in a laboratory setting in a dish stimulate nerve growth and so you know at face value you might say well creating a few more neurons if you're especially if you're losing neurons due to you know dementia or something else might not be a bad thing so there's a kind of plausible biological mechanism in terms of kind of studies in people the jury is very much out so there have been some studies uh demonstrating slight improvement or or a slowing in reduction of brain capability in people with early mild cognitive decline um small studies uh not highly replicated yet so you know be cautious but perhaps slightly promising uh there was one interesting study that people often talk about a lot on social media where people without any cognitive decline relatively young people showed an improvement in their mental score on a kind of classical test uh which actually is a test where very it's very rare to see things that improve that score in people who don't have cognitive decline so so you might see online people say your iq will go up if you eat this uh you know which is off based on those kind of studies um again very very small very limited there has been at least one study which is showing the opposite which is showing if you have it your your ability to recall words drops um and so like much much of science i think we are still a long way from a kind of solid answer and so when you look at all of that you know i think a lot of what you're taught right is to discern the different quality of evidence across these studies what's your guess about mushrooms and their ability to have any impact here yeah i think i would happily wager a mortgage payment on the fact that somewhere out there in the fungal kingdom there will be you know fungal products that are going to be massively beneficial for medicine and therefore longevity and i wouldn't rule out the possibility that you know in the future there will be particular species or particular extracts that will be recommended for everybody to take if you enjoy it it fits into your lifestyle there's no evidence of harm but i definitely wouldn't you know go out of your way to take a particular mushroom supplement in the hope that it will help you live forever i'd like to share my favorite healthy habit with you it's called daily 30. 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long-term inflammation is not something you want to have but we all have this like high level of long-term inflammation living in the western world compared to to the past is there any evidence that eating mushrooms can have any beneficial impact there so i think it's really important to think about again about this kind of breadth of the fungal kingdom here and you know because i've spent quite a lot of my life working on on fungal diseases that kill people i do want to kind of emphasize the fact there is a spectrum here right there are fungal species that are probably very good for us and we eat there are fungal species that you know you really don't want to get this is your i have athlete's foot but even though it is a fungus it's not a good thing i was thinking exactly i think so definitely not great although that's more in the annoyance but there are you know a handful fungal species that are potentially fatal particularly for people who have weakened immune systems i think really important to stress here that you know if you are thinking about how can i prop up my immune system because it's already impaired i've got the genetic disorder or i've got hiv positive or something uh you know dietarily absolutely fine but but you know if you read someone's magical thing about sniffing a fungal spore just don't do that but that notwithstanding i think one of the things about fungi generally is that many of the molecules that are present in fungus particularly on the surface do have quite potent immune effects in in humans and other animals that's largely i have to say because the immune system has evolved to react to and get rid of fungi it's not a good thing to have fungi growing in your lungs for instance if you think about that cell wall of the fungus most fungal species have a molecule called beta glucan inside that fungal cell wall um that's a really potent immune stimulus so if you put beta glucan into somebody their immune system lights up because it's trained to say here's something i should react to and get rid of it and in fact we use beta glucan as what's called an adjuvant to help some vaccines really generate a good immune response and so there is definitely immune effects in fungi less clear is the kind of ability of the immune system of fungi to suppress the immune system so there are specific examples particularly in some pathogenic fungi of molecules that the fungi use to deliberately suppress the human immune system but that's for their own advantage right that's because they want to grow um and so i definitely wouldn't recommend people expose themselves to those two i'm here at the moment whether similar molecules in fungi that are not harmful might be beneficial um so so yeah sort of jury's still out probably the last thing to say on that though is there's also a sort of secondary effect in that fungal products are really important for influencing the microbiome of the gut so for example many of the sugars and the carbohydrates that fungi make are really good kind of foodstuffs for the bacteria in your gut and so there has been quite a bit of evidence that some mushroom species will help stimulate a kind of good microbiome for want of a better word and of course the good microbiome can have a very strong positive effect on your immune system so it's interesting you're wrapping up on a topic that obviously we love on this this show and you're saying that perhaps one of the most valuable things that these mushrooms are doing is actually to be food for our gut microbes and they might then be producing these compounds that are beneficial for us exactly exactly this is a lot like a plant where again there's lots of things here that i can't digest directly and so if i want to get the benefit i need to get the the microbes to sort of break it down for me yeah exactly so there's you know and we we often sort of overlook i think the fact that your your microbiome is this wildly complicated ecosystem and if you think about the relationship bacteria and fungal species have been evolving together for you know obviously far far longer than we have and so there are some really quite complicated signals so if you look for instance out in in soil you know there are really well documented situations where the bacteria might make a molecule the fungus picks it up and behaves differently it produces a different molecule the bacteria changes its behavior there's a complicated conversation going on uh we're only just starting to scratch the surface of that but very reasonable i think to think that when you eat a mushroom you're probably plugging into that evolutionary conserved kind of communication system and having an impact on the on the bacteria that live in your gut are there any funguses that should be growing in my gut or is it now clear that like bacteria are great but that's again one of these big distinctions we don't want any of these fungi and therefore our immune system does not play nicely with them that's a really good and very very live kind of topic in you know if you go into social media lots of people with strong views there historically you're right so people have historically sort of said fungi growing in your gut bad thing and and in some circumstances that is definitely true like most things about the gut you don't want dominance of a particular species for instance that said it's really only in recent years that we've started to understand a bit more about what appears to be the kind of natural fungal microbiome of the gut and that's largely speaking because they are massively outnumbered by the bacteria so early genetic sequencing you know you just take your abundant dna and it's only with the advent of technologies which allow us to look at very rare very low levels dna that we start to see these fungal species um and i think kind of an emerging view that there are definitely some species that are probably quite good to have in your gut uh still very unclear which ones those are and what they might make the difference for them but i think that sort of realization that fungi are kind of everywhere and are part of your natural microbiome very important and in fact uh you know outside of the gut so skin for example you know we're covered in interesting fungi um they do all sorts of weird wonderful things my favorite example being something that grows only really on the human head and in fact is only able to reproduce in the presence of human sweat excretions so there you go you're now kidding me nope there is a fabulous uh demonstration that this particular fungus is completely required so i have a colleague who says it's a creepy feeling to think that there's a endangered species that can only have sex on your head there is a fungus that can only grow on the human head and cannot reproduce unless it gets the particular like sweat that comes off from the human head yeah it's the oils that you produce in your head that seem to be a signal for it to to sporulate or to produce the reproductive organs that's fascinating this is this example of how we are this ecosystem with these tiny microbes and that includes fungi we talked about bacteria a lot we're saying there's fungi that absolutely only coexist with us yep you know you might think that's just a parasite but is your view that on the skin some of these fungi are actually beneficial to us yeah absolutely and in two different ways so there are probably some species that are genuine sort of symbionts so they're there they never do any harm and they're kind of good for for uh you know whatever reason they might be helping to sort of digest things you don't want or they might be kind of helping to regulate the immune system but also there are there are species that are sort of at face value potentially bad news but their presence helps with this kind of maintaining a normal immune system so one that's often talked about is candida um and there's a sort of whole uh world out there of kind of candida syndrome and kind of things and people so candida is absolutely a fungal pathogen that can cause serious disease it can cause you know vaginal thrush or thrush sometimes systemic lethal fungal infections but all of us have candida all the time if i'm going to go and swap my armpit you'd find candida there and that's not a bad thing it's there it's kept in check by the immune system and it's probably helping to keep our immune system in balance so you know as with many of these things you don't actually want to be a sterile site it's good to have a healthy microbiome even if it includes things that can on occasion go go bad absolutely fascinating i also heard that mushrooms might have a cholesterol lowering compound is that true that is true um so they produce in their cell wall this molecule that mentioned earlier beta glucan so the main the main structural component of the cell wall is chitin that thing that's in lobsters and beetles and things um but they also have this layer called beta glucan and beta glucan is a uh it's a it's a polymer so it's a chain of sugar molecules glucose molecules we talk about beta glucan but actually this is a whole family of molecules because if you think about joining your sugar molecules together you can put branches on them you can do different things so their structures are all quite different however um what appears to be pretty clear now is that when we eat beta glucan it can kind of form a sort of gel in our in our guts and that gel is actually very effective at absorbing cholesterol keeping it away from your cells especially ldl so the kind of bad cholesterol um and then essentially getting pooped out the other end without you taking up too much so this is the same group of molecules that is what makes oats really good for you so our recommendation to eat oats oats are great at helping to lower cholesterol uh fungi produce less beta glucan than you have in oats but nonetheless quite a significant amount so if you're already having oat porridge uh great i wouldn't swap that out for a mushroom in the morning but if you're taking mushrooms additionally it's another good way to help lower cholesterol i would like to talk about actionable advice about like how can i actually add mushrooms successfully into my diet could we talk about the cooking for a minute because i always feel that when i cook mushrooms it feels like the darn things basically disappear right it's really big you've got on some heat and it just like shrinks and shrinks and so i've always sort of felt well i've probably killed everything that is of any value because it all shrunk away is this right not necessarily so um heat does remove particularly vitamins uh you know levels of vitamins drop quite dramatically when you heat especially for a long period of time um having said that of course depending on what you're doing with your mushroom you might not be heating for very long so if you're kind of frying a mushroom you're gonna think about those big fat delicious field mushrooms you know you might give it a minute on one side and 30 seconds on the other and you're done so actually in that sense you're retaining kind of more vitamin than if you're going to put in the oven for an hour probably the bigger risk with boiling is the water solubility so a lot of these things that are in mushrooms are highly water soluble so vitamins b and c but also things like potassium are very water soluble so if you're going to boil your mushrooms and then throw away anything they were boiled in that is leaching out quite a lot your nutrients if clearly if you're boiling it in a pasta sauce you're going to eat your pasta sauce not a problem you've just moved your potassium from inside the mushroom to outside a bit like i think how i was brought up to do carrots you know if you're putting a great big pot of water then you throw away the water it's like literally you're throwing away the good stuff the good stuff yeah exactly i mean my my usual you know best rule is the best way to cook something is the way that you're going to eat it uh you know so if you're if you're someone who uh you know will only eat a mushroom if it's been cooked for a long time then that's fine because the alternative is not to eat it at all what about preparing the mushrooms one thing i'm always struck by it's a mushroom comes it always feels like it has like dirt and mud on it i always feel like well i gotta like sort of scrub the dirt off it also puts me off a bit eating it you know back in the old days you say oh you should peel your mushrooms um actually you know that's relatively if you're worried about the dirt component there's relatively limited value in peeling because as we know the bottom bit doesn't have a skin on to peel anyway and the stalk doesn't and so on so you're still you know you're not removing that much so i wouldn't worry about peeling for sort of aesthetic and general kind of taste reasons it's a good idea to give them a polish off or a wash off and get rid of you know any soil that's left on them the world of raw mushrooms i think is one that we've got to be slightly cautious about because like any raw food there will be other organisms present there bacteria viruses whatever and so they are potentially a risk because of the way mushrooms grow and the fact they're quite difficult to clean well that is potentially slightly higher than with other foods um so if you think about you know an apple for instance you know it's relatively easy to clean the surface of an apple in a way that you can't do with a mushroom if you're picking a mushroom straight from the field uh you know you've got no control over what's on that mushroom and so as with all foods the risk of you know potential food poisoning is is higher you know i might caution against eating that one raw the last thing to say is there are some compounds in many fungus species including fungi that we eat which can be slightly harmful um i want to kind of caution here but there's a kind of level thing but there are molecules called hydrazines for example that in laboratory studies appear to be damaging for dna so their potential carcinogens cancer causes they're at pretty low level so this is definitely not a reason to not eat mushrooms but they are also broken down rapidly by heating so so if you're someone who's really wild about mushrooms and eats a lot of mushrooms eating a really large level of mushrooms raw is maybe not a great idea and i might be tempted to cook them a bit more partly for the food poisoning reason and partly for this kind of question of residual damaging agents my takeaway from this is i probably don't need to worry about the dirt as much if i'm going to cook it and so i can probably be a bit more relaxed and not let my ocd loose on the on the mushroom yeah i think if you can get over the psychological barrier of eating a bit of sterilized horse manure with your your pasta sauce you're fine would have been easier if you hadn't put it that way what about how to cook mushrooms in a way that actually just like maximizes the pleasure and taste it's very difficult to eat something that's good for you but you really dislike so i would encourage people to kind of go out and and try different mushrooms um because there's lots out there um and they're all very variable loads of people i think like you said your your son and my son also really dislike mushrooms when they're young because they're kind of slimy texture quite a lot of people actually get over that when they're adults but they often don't know so i think if you're listening to this you're an adult you think well i don't like mushrooms but i haven't tried them for 10 years give it another whirl because maybe maybe they're not as bad as you remember this is a hugely diverse kingdom so we have to think about this not as mushrooms but as vegetables in the um and so i think think kind of testing different ways using them in different kind of settings is a really good thing to do think about the way of cooking it so some mushrooms become much more edible you know when you fry them some become quite tough and stringy some are great when they're ground and powdered some just taste like dust um and so there's a sort of sense of the diversity of mushrooms out there and also the kind of way you're preparing them and last thing i think is think about the kind of meal you're using them in and the strength of uh you know experience so i i you know i think there are a lot of people out there for example who've had a very bad experience with truffles uh because they get this thing that looks absolutely tiny i think oh i'll chop that up and throw the whole thing in and then they realize that you know they're tasting truffle for a week afterwards um these are really potent species some of them so uh so go steady try it as you go a bit like think of it maybe as a bit more like spices than than uh you know kind of a core component if you're thinking about these more unusual ones and and test the flavors first before you put the whole family off there's a diversity that we just don't appreciate because they're relatively new the diversity of them is relatively new to the western diet i think so we're still like well what is this weird looking thing and how do we cook it and if someone's listening to this and saying i want to add some more mushrooms to my diet i'd like to maximize the potential benefit from doing that so yes i'm only going to eat it if it tastes nice because obviously i'm not going to stick with it otherwise what would you be saying about the specific types of mushrooms that they should be trying to add the single easiest thing to do is a few fried mushrooms so it's quite easy to add them as a sort of supplement side to things you're eating if you don't like mushrooms or someone your family doesn't like mushrooms uh you know i think like with many foods you can get around that by sort of small than invisible incorporation so i think there's there's many a child who avows a hatred of mushrooms but if you chop them really fine you know they won't particularly notice these days you can quite often buy from sort of supermarkets these kind of mixed boxes of different mushrooms if you're someone out there who's only ever had the classical kind of white butter mushroom you're like i wonder you can pick up a kind of mixed box uh from mainstream supermarkets and give it a whirl you know an oyster mushroom or uh you know some of these kind of slightly more exotic ones that might open your eyes a bit more and you know and then if you really get into it you can discover a whole world of interesting you know pig's ear truffles growing on elder plants and and is one of the takeaways from this that just like when we think about plants one of the biggest things that um we talk about is like trying to get this diversity of plants because they're feeding all of these different microbes should i simply be thinking about this as i really want to get a diversity of mushrooms into my diet rather than there's just like one mushroom which is the best mushroom and so i should just make sure i'm only eating that one we don't have the data on that uh yet obviously in the same way that we do for plants um but you know i'd be pretty confident in suggesting that diverse mushrooms is probably better than a lot of a single one and actually you know that's kind of a rule for life like binging on a single thing is generally not advisable so even if you love mushrooms you know i wouldn't eat a kilo a day um so think about that kind of diversity um particularly when we're thinking about the impact on the microbiome the microbiome loves diversity so different fungal substrates for your microbiome to grow on is probably going to be beneficial given all of this robin do you eat mushrooms and if so what do you eat i do mushrooms i love mushrooms and actually i mean like many people i'm sure listening to this mostly it's your traditional kind of field mushroom type thing um but you know if i get the chance i do like a oyster mushroom in particular the occasional truffle you know if i'm eating a mushroom my kind of favorite way is is fairly sort of straightforward so you know heaping mushrooms next to an english breakfast great uh one of my go-to recipes as a student back in the day was you know these really big fat field mushrooms that are usually quite expensive but you know top tip last thing on a sunday at supermarket they're usually selling them off cheap because they're going to be horrible tomorrow and you can stick some breadcrumbs and some lemon on that and a bit of cheese on the top stick it under the grill great and relative and the cheese is not so great for you but everything else in there is pretty good for you amazing i'm getting hungry just think about it finally if you were going to give one tip for someone listening for how to add more mushrooms to their diet like next week you've given us many tips but what would be your your one tip uh can i do a tip and an anti-tip yeah so so my anti-tip is please don't do this by going out and thinking that's the thing it looks like a mushroom on my floor and i'm gonna pick that that's a very bad idea uh do go to a supermarket or reputable retailer first that's my anti-tip um my top tip i think i would probably be to can just think about mushrooms a bit more like we think about vegetables rather than this kind of special thing so if you're thinking i'm gonna do chicken fillet tonight you know uh i'm gonna do some carrots what else should i do with it think about a mushroom rather than a frozen pea or maybe as well as a frozen pea um uh think about mushrooms as a kind of vegetable component that you can put into pasta sauces or things rather than this special thing that you have to somehow put your mushroom cook hat on to deal with i love it robin i'm gonna try and do a a little summary and just correct me where i i get anything wrong so the thing that's sticking with me most of all is that there's a fungus that can only grow on the human head and ever since you pointed that out i've been thinking about this while looking at your head and it shows how we like coexist with fungi at this incredibly deep level the other thing i think which is extraordinary is this idea that humans are actually closer to fungi than plants are to fungi and that does sort of transform the way you think about them as clearly being this source of all of these compounds that you're just not going to get even if you are eating a lot of plants and that definitely shifts my my thinking about like oh i'd really like to have more of these mushrooms in my diet because i'm really trying to get that diverse diet and the one of the reasons why they probably work is you're saying mushrooms are great food for your microbiome so actually your microbes are going to love this they're going to feed a whole bunch of good microbes they can break them down in a way that our body can't and then give us these other benefits i clearly need to have some oyster mushrooms in my diet because apparently there's a hundred times more vitamin d and since i do live in you know northern climes in the winter i can see the oyster mushrooms that i need to remember to put in the sun are a way forward there are some amazing nutrients that are inside these mushrooms you describe this thing that i had never heard of before the ergothioneine that is like a whole amino acid that i didn't even knew existed that i can't make that i don't get from plants and you said like in the lab it has some really interesting properties for some reason like all our human cells can take it in but we don't really know what it what it does and interestingly even just like a button mushroom can have this and this is just an example of the way and like how unique they are and you talked about them being full of potassium and selenium and vitamin d and vitamin c and beta glucans all of these things um that you don't have the other thing that i was really struck by is the idea that we probably all do have fungi in our guts but it's just at very low levels compared to bacteria so it's going to be small and the latest science is suggesting that we shouldn't think that all fungi is bad for us just because we know that you know you can have overgrowths um in various ways so actually probably it's natural and good to have this like low levels inside us and i think that would be fascinating thing you know to understand more in the data as this continues to grow and then finally we talked about how do you get mushrooms and i think what's striking is any way that you get the mushroom is basically going to be good so like a dried mushroom is still going to be good it's not like you've lost all the value if you cook it it's actually still going to have benefits the only thing to be cautious of is if you boil it make sure you drink the liquid otherwise you are literally putting it into the liquid and throwing it away and that it's very easy to add because it is something that you can eat as a side so if you're finding it otherwise difficult you can always just put you know fry some mushrooms put it on on the side and so for me like my final takeaway is i need to stop thinking about it as occasionally i have this special mushroom dish and just think i need to make sure that i have like mushrooms in my supermarket shop each week so that i am eating some mushrooms every week alongside the rest because i'm just going to up this diversity and it's this amazing whole new like kingdom of things like surely i should be trying to get some of that into my diet that sounds like a perfect summary i hope you've convinced your son to go into the world of mushrooms if you enjoyed this episode with robin i know you'll love watching this episode with merlin sheldrake in it he shares the fascinating hidden world of fungi and how they might support your mental health