What Role Does our Microbiome Play in a Healthy Diet?
thank you very much and you know get it suddenly a diverse series of talks today so we can look at it a bit of the universe inside our own bodies the sort of opposite of what we've been seeing before and I want to just before we get into that just tell you a bit about how I got into this myself basically was about about 3,000 meters I was doing something called ski touring in Italy which is a strange rather silly sport we walk up for six hours and you ski down for an hour and it's very tiring and at the last day and I was really what feeling well I started falling all over the place and I thought this is just the end of a long week got to the bottom and I had double vision and this persisted and being a medical doctor I realized this wasn't good news that Yves either you know M s brain tumor or some form of stroke none of them were particularly great and so after a very stressful few months of scans and things turned out I had a very small occlusion sort of micro stroke if you like of one of the vessels supplying the eye nerves now my blood pressure went up and suddenly I went from being healthy to being like most people slightly unhealthy with some disease taking tablets and wanting to help improve my health and I thought I'm a doctor I've been studying obesity genetics for 20 years should be fairly straightforward to work out the best way to lose weight and exactly what to eat and I was completely mistaken nothing could be harder and when you went to the Internet you were faced with masses of quackery and obsessional religious groups stating that their their way was the only true path to salvation and also even the and so advise the public health England advice about nutrition yes it contains some facts which were accepted by everybody eat more plants and vegetables eat a bit less of it eat less processed foods and less sugar but at least half of it was extremely contentious and without any evidence base such as eat less salt have more starchy foods eat regularly small amounts and often rather than in short periods eat have food supplements and use artificial sweeteners rather than sugar and above all count calories and all this is without any real evidence base some of it has actually been disproven by other randomised trials so and the whole idea really of the last 40 years in nutrition in telling people to count calories has been totally flawed even the most hardened obsessional nutritionists cannot possibly count their own calories even if they read all the labels and you only shop from a place that's counted it even those have huge errors in them so if everyone's if we've been counting calories and our obesity rates have been going up threefold over the last 40 years something's very wrong so this was all telling me at the same time as I was working on another field from the twins that there might be something else going on and that's something else that to explain all these discrepancies and what this was was for me the understanding that there's a new organ in our bodies a newly discovered organ that we call the microbiome which is the community of microbes that live in our bodies on our bodies we're surrounded by it everywhere in this room but in ourselves 99% of them live in our lower intestines and this community which includes bacteria fungi viruses and other organisms could archaea and protists all live together just like they do in New York it nice happy groups and the best way to think of them is as a new organ and together they have as many cells there were many morgen isms as there are cells in our own body and they have maybe a thousand times more genes and each of those genes is capable of being a chemical factory that can pump out all kinds of chemicals proteins hormones that our body lacks and so we can't live without them and we've rediscovered recently how important they are to all facets of our life and particularly how interacts with our diet now no two people are the same all of you would share 99.5% of your genes with each other your DNA and in fact you can turn around to everybody in this room and say isn't it great we're all fifth cousins some of you might be third or fourth cousins really close and so we realize that actually you know as as a group of people we're very similar but if I asked you to compare your microbiomes you wouldn't be anywhere near fifth cousins you'd probably like 10th or 12th cousins because you don't share about 25% of your microbes with each other and all of you are going to have very individual microbes unique microbes only to you and so that for some reason they like only you they don't like your neighbor and used to be privileged that they've decided to take hold in your bodies not someone else's because generally these things are good and this individuality explains why there isn't really one diet fits all it explains why when you put identical twins on diets as they've done here some you get different as well as differences between the twins you also see differences in the population of four fold differences in how people will gain or lose weight on exactly the same food and we've all seen that wall seen some people that seem to do very differently and they said I only eat lettuce and Nolan says aye-aye masses of cake every day and we've always said all that must be genetic or metabolism or something we but it turns out it genes don't explain much of it and most of that can be explained by the differences in our microbes now these microbes do all kinds of things I'm going to explain all this but just just to open the scope of what these these guys can do they can alter whether you're likely again allergy and we're in epidemic if you haven't noticed of food allergy at the moment in young people whereas I didn't know anyone when I went to school who had food allergy now everyone's got it and these microbes are the keys to allergy about how our immune system recognizes threats and and gets it wrong or right we also they they can change chemicals in the brain making you hungry or thirsty R or choose certain foods certainly in insects they can do that decide what you want to eat they can also alter your mood they produce metabolites like serotonin which are responsible for anxiety and depression and many drugs are based on that then they can do all kinds of things about controlling how your whether your gut is leaking or not on all kinds of other systems of how you digest foods so it's huge and we just at the tip of the iceberg really about discovering all the things that these guys do now to summarize masses of science into one picture is tricky but I've at a stage in life where I can do this without people telling me off because people say well what is this microbiome stuff I've heard of it but it every study varies a bit and is there really one microbe that is responsible for one disease and the reality is no the studies do differ they've been relatively small but there are some consistencies what we find in every single study where we can by compare people a group of people with a disease say it's diabetes or it could be colitis or food allergy or Parkinson's or depression whatever it is with another group the super healthy will always find that the group with the disease have a less diverse microbiome community they have less species if you count them up that'ss aren't those number of plants if you like and so that's why I've used the analogy here of the garden the English country garden is what you would like to have okay so you guys are all super healthy you've got English country garden type microbes lots of different species all interacting with each other and a fertile soil that contains both fungi it's got microbes and everything's feeding off it shot each other for any keen gardeners will know what I'm talking about that all those nutrients are used it's all being recycled and it's very hard for invaders to come in and take over whereas the sick people there their guts look like an Arizona backyard okay bit of toxic waste a few nasty bugs they're taking over it's very easy to transform that and you can just visualize how them are products helpful products produced in Arizona backyard are much less than in your English country garden they're producing all kinds of aromas and chemicals and things for all the insects and the roots and everything is is far more productive so the more you've got of these guys the better it is that's the that's the main key here now we did something called a citizen science project for the last few years with our American cousins and this was people who were interested in their gut microbes we're donating they're paying for their own research really and you can still do this if you join the British gut project you pay a small donation and then you give a small donation of your paw it's poop we call it poo in the post and you send it back to us and we sequence it genetically in the same way we would look at your we look at the microbes and that's how we discover what all these species are then we put it all together big computers and start looking at these patterns and this is of 11,000 people and we can clearly show some patterns we can clearly show differences between Americans and Brits just based on their microbes and we could tell differences between northerners and southerners and of people living in the country and people in in towns now we can't go to individual differences in terms of microbes but we can see those patterns and the good news is we're not quite as unhealthy as the Americans but we died but I think we do pretty badly on the world scale and the one thing that determined this summary health gut health if you like which I'm calling diversity where you want maximum diversity the number one thing we found was not whether you were vegan not with your vegetarian not with you gluten-free or lactose free or any one of these other religions but actually than just the number of different plants yet every week okay and I'm talking not just you don't have to have and that doesn't mean having 20 portions of kale every day it means having different seeds different herbs different spices and it's mixtures of fruits and berries and nuts and all these kind of things together because each of those are fuel for your microbes and that was more important than whether you self said I'm a vegetarian I'm a vegan I'm healthy I'm I'm a paleo person I'm whatever okay so that's the key so you can do all those other things call yourself what you want as long as you got lots of variety on your plate you don't get caught in a rut now the government tells us to cut down on sugar and they also tell us to cut down on antibiotics and we know that antibiotics are really bad for your guts and today they're given out like Smarties but we know that children given antibiotics do get fatter and do have more allergies it's very hard to avoid because a lot of antibiotics are in our food in our meat particularly if it's cheap or processed meat emulsifiers come in all kinds of sauces and we know that emulsifiers in processed foods do also influence your microbes make them stick together a bit stop them working preservatives we we know less about but we're worried about them but we do know that artificial sweeteners so how many people here take an artificial sweetener on the basis that it's supposed to be healthy anyone admit to taking any one of you well there must be more than that but ok ok so Jenny there's supposed to be inert right not supposed to do anything I went into a metabolic chamber and took some sucralose which is the Communists one in the UK at the moment and that's my you can see my glucose went up I was wearing a 24-hour glucose monitor and so just having sucralose it peaked and this was tell me that these things are far from inert and there a number of studies now showing they reduced diversity and increased metabolic signals so a whole idea of what foods are safe and non safe needs a new thought when we start to think about our gut microbiome as a novel organ in our bodies it's part of my book the diam if I did lots of studies and I'd just come off a rigorous three-day raw so raw milk French cheese diet you've obviously tried it yourselves help down only with the help of a little bit of red wine and it's it was fantastic just eating it wasps rock four and brie de Meaux which are three unpasteurized cheese you can easily get in the UK because they have extra microbes and I was trying to see if I could build up my microbes in just three days I didn't does it matter of fact but I did enjoy very much the day one of the the dark day two not so good by day three I'd really had enough cheese for the week I could tell you and the next study I was going to do was to do the ten days McDonald's challenge bit of a contrast they're only all my meals at McDonald's and I wasn't very looking forward to it because I wasn't a big not a big fan but I do anything for science of course and it turned out there was some better qualified than me someone actually liked eating burgers and fast food he was a student he was hard up for money he was also my son he ticked all those boxes fantastic so Tom did this and all his friends used to follow him into the McDonald's and take pictures of him because he was getting all this free food and everybody the staff knew him for those ten days but he he came back to me after just four days and said I'm really not feeling very well my friends say I'm going bit gray and I think we ought to stop now and as a concerned parent obviously I was worried about his health but said no way we're going to carry on we're gonna publish this in The Sunday Times which is exactly what we did and when we published in the after ten days he really was feeling even worse and we even noticed even in him a drop in his academic achievements which was something but what was worse as he'd lost 40% of his gut microbes so his diversity had plummeted in those ten days and really we had to ask the reason why that was because the traditional view of junk food if you like oh it's just lots of fat and lots of sugar it's most of naive idea and maybe chemicals that's why shouldn't have it but from a gut microbe point of view what happens when you have that kind of diet you're not getting any fiber at all they need fiber to live okay the only fiber is a little green gherkin that the most kids throw our way anyway so he had ten days with virtually no fiber and lots fat on lots of sugar and I think it's that imbalance that really messed up the gut microbes messed up his gut health and that's why we just need to think differently about this that's what it'll it's the lack of something rather than necessarily this idea that these things are all toxic we need to be stinking up because microbes are good the more you've got the healthier you are the better you are if we destroy them other ways then we're in real trouble now he stayed bad actually for several years as he kept reminding me when he wanted more money but I think we may have finally sorted them out now now that's just an end of one study obviously and an anecdote enough in our twins that we follow half identical half non identical we followed a group between thirty and eighty-three thousand of them that we had very close measurements over because we've this is the most detailed study of twins in the world that we run and we have every few years they come in for a test and a body composition scan and we saw that over that time as usually mid late most people gained weight very unusual not to and those that had high fibre lost less weight and particularly weight around the gut the internal visceral fat then those that hound low fiber diets and each extra gram of fiber people at reduced their weight gain by two kilograms so even a tiny amount of change in fiber seems to have a very big effect and this was related to their microbial diversity so we could redirect Li link what they were doing with how it was changing the microbes so we seem to now have a better understanding why fiber is good for you it's not the old days of oh it's just roughage it just passes straight through you and gets rid of toxins which I was taught you know a very physical presence of it as a like a substance to just you know cleared scouring the inside of it and cleared everything out now there's a real metabolic understanding that this stuff is there fuelling your microbes we also looked at the genetic of this because in our twin study virtually everything we look at turns out to be genetic except whether you like mr.
Bean or what football team you support and this turned out to be a bit of an exception it's not very genetic at all it's about 10% or so heritable some microbes are genetic but the vast majority seem to just go with the environment you live in and in your diet that was important for us because it suddenly realized the potential to change your microbiome is much greater than to change your genes now the other thing we looked at was pairs of identical twins remember these are genetic clones where one was much bigger than the other one and you can't explain that in terms of that upbringing because they live together till the age of 18 generally and you can't explain it in terms of their genes because they're identical every cell in their body so this particular pair differed by about 15 to 20 kilograms over most of their adult life and when we added up these pairs we found that in nearly all cases the skinny one had more diverse microbes and had particular microbes that liked them and not their sister and there are a couple of these that call Kristensen eller and a common SIA that we only found in the skinny twin and when we looked we about 10% of people have these Kristensen distresses another microbe and the people that have in high numbers always tend to be on the skinny side and some people reported they could eat whatever they liked snacking on things they never got fat aren't they lucky and when we took these microbes from the twins and put them into mice we could stop them getting fatter now that shows you that it isn't just an association due to being skinny or being fat but actually it's it's part of the causal pathway and this is the clever thing about gut microbes is you can do the experiments in humans but you won't know whether it's cause or effect and then you can take those microbes Transplant them into these animals and make them fat make them thin make them depressed make them anxious do all kinds of stuff to them change their immune systems and this is why we know that they're so important and not just bystanders in what's going on so this is really important and there are companies now trying to experiment with these microbes putting them into breakfast cereals and things so everyone can eat as much as they like and stay thin they haven't succeeded yet though that's how to do badly how can you improve your your microbes I guess is the other question and then if any of you listen to the Food Programme on Radio 4 so I went with Dan Saladino to Tanzania and an anthropologist called Geoff leach who's been studying the Hadza who are a tribe that have been in this part of Tanzania for about 10,000 years possibly 50,000 years in exactly the same way of life so one of the last hunter-gatherers on the planet and they have 30 or 40% more microbes than we have even the healthy other stuff and they don't get chronic diseases that I don't get fat they don't get diabetes they don't get heart disease that I don't get cancer they do fall out of trees and have other injuries and infections etc but they don't have any of the sort of allergies or disease we have so we think it's their way of life we think it's their microbes and I went there for four days to live with them eat their meat and basically at what they did no washing facilities obviously in the middle of nowhere and as well as the fascinating time I did manage to improve my microbes by about 20% or so in terms of diversity but there was only a short-lived effect as soon as I got back on the aeroplane home and started eating aeroplane food I think everything dropped back to where it was so I need to stay there a bit longer or keep going back there for a top-up but it does show that by changing diets and environment you can actually improve to some extent your microbiome a bit about what the foods are good and bad for your gut microbes everyone knows and knows green vegetables good high in fiber and there are certain fibers that are better than others and the fibers well at least that we've studied them more and so the ones we've studied as a something called inulin which is in particularly in vegetables such as artichokes both globe artichokes and Jerusalem artichokes also known as farty chokes that will have masses of inial in which the microbes break down and convert into very helpful things called short chain fatty-acids so they they're converting this as a kid like Kelly as I said they're chemical factories converting the chemicals in the plants you eat into other useful substances so knowing which ones these are onions garlic leeks all have very high amounts of these in it and also we know the legumes are useful and then we have things that also have lesser amounts of fiber but have other things that are important so in the past we've been told that drinking coffee is bad for you peanuts are bad for you red wine is bad for you olive oil is bad for you but it turns out but all these things and dark chocolate bad for you turns out the recent evidence is that it's all good for you so okay but the reason it's all good for you it's not just we got it all wrong before it's because they all have some chemical compound in them that the microbes use and that's called polyphenols okay so polyphenols have been around they used to be called antioxidants which was just a general way of scientists and doctors pretending they knew where they were talking about because no one really understands why we these things were were helpful it was just a general word for things that mop up nasty things but this is a much better theory because these polyphenols we can't actually use ourselves but for the microbes it's rocket fuel they love polyphenols they break down they get these polyphenols they use them as energy sources and they then convert that into other helpful chemicals for our the lining of our garden arm you system so it's a sort of a good deal basically we get and that's why the Mediterranean diet is particularly good for you because of all these polyphenols despite the saturated fat that traditionally we're told to avoid and that's then yeah and then we've got a few other things in here so you got you can see some yogurt there how many people here have yogurt every day Wow look at you like you like commercial how many people here have keffiyeh okay who hasn't heard of kefir okay calf Ares is the new super yogurt okay you you will have heard now you've heard about it but you'll start seeing it now when I wrote it's interesting when I when I my book first came out a couple of years ago no one had heard of kefir and suddenly it's sunny where I live in in Islington it's in every shop you know you you can't move for bloody kaffir so but basically it's it's soured milk fermented milk and it has about five times more microbes than the equivalent amount of yogurt so do get used to it if you if you if you like yogurt mix it up you know and start having that as a top-up if you want your microbes how many people here have kombucha I've got you there okay kombucha is the next level you see once you've once you've mastered kaffir you go to kombucha which is fermented tea so basically you get a it's and it comes from Russia and it's very big in California but it's taken ages to get here but it's it's it's a fantastic drink and it has about two or three times more microbes even than kaffir and you have fungi in there but three times a funghi basically grow this mold thing that's got a mother it's a bit like a sourdough mother and you put it in your tea and after 10 days it converts the sugary tea into a really refreshing drink that has a slight sour acetic acid taste is packed with good stuff okay so we're diverging slightly I could do the whole kombucha at all but just to show you that these interesting foods all have this common theme they're all really good for you gut microbes either as few or as providing actual microbes themselves okay these probiotics meat-eaters how many vegetarians in the audience not many okay that's probably generational now it's about one in six of the population is vegetarian less a vegan but a lot of people give it up meat because they say it's bad for you it's bad for the planet they're partly correct and most us they do show a slight harm of red meat over not eating meat it's mainly processed meat that's particularly bad but some people maybe I do eat meat fine it turns out you're microbes can determine whether you're someone who processes meat in a healthy way or you produce waste products that give you heart disease and so they've done a number of studies now that show that this is just subtle difference in how our microbes break down some of the carnitine in meat to other chemicals makes a big difference and likely many other examples of this what we call personalized nutrition this was just to show you that there was a headline a few weeks ago that pre probiotics don't work remember that no well the idea that eating yogurt doesn't work because all the microbes get destroyed turns out that's partly true most of the microbes get destroyed but if you have a billion of them there'll always be a hundred thousand or so that will get through and replicate but they don't hang around in your gut basically they're there to act as chemical signals for the other so they stimulate all the other microbes and you get a big metabolic difference so when we start measuring not the microbes but the chemicals they produce we see big differences between yogurt eaters and non your get eaters and those same micro metabolites they produce the chemicals we've shown are actually good at reducing some of the internal fat using our twins study so it's just add another way of looking at it thinking them as chemical factories makes you understand a bit more why you're going through all this and why so many of you eating your yogurt because you obviously think it's good despite the government telling you it's got fat in and you should avoid it you should always have the full fat one by the way not the the low fat one if you want to get most of the benefits now just closing up the there was a study a couple of years ago have you heard of glycemic index of food so this is on packets where they tell you this is what the carbohydrate content is and you should if you want to be on a you know avoid sugar spikes and things like this you should pick low GI foods well it turns out that an Israeli group studied this and found that actually what was more important than your GI index of your food was what your microbes were doing okay so for some people what's good turns out to be bad so for me if I have grapes my blood sugar goes up into the diabetic range of 9.4 if I have bread my I shoot up to about 11 or 12 which is not good but I can have as much pasture as I like I can have as much rice as I like I can drink as much beer or wine as I like so I'm happy as long as I don't have too much bread but I wouldn't know that if I hadn't done my own experiments and what we're hoping is that we can start to measure people's gut microbes in order to predict which foods they should be preferentially having so everyone should get some personal nutrition we've started this huge study in the UK in in our twins called the predict study and we've done 300 twins so far doing this kind of two weeks of food logging all their foods looking at their their sugars with these glucose monitors that you know I've got one on at the moment you can now wear them for two weeks this shows that one one twin spiked when they drank Prosecco and the other one didn't and one spiked with rice and the other one didn't and these are just small life choices that you can make that if you thought about this regularly you would know this could make a big difference over year is just by changing what your lunch was or what your favorite drink was it's not like cutting out huge food groups it's just making small choices that your microbes prefer I found out that my average lunch at the hospital was tuna sandwiches and bread thanks for Marks and Spencers for 10 years because that's what we had in the canteen and I thought that was healthy it's gotta be a sweet corn and it turns out that was every single time it was giving me a glucose spike and probably responsible for me gaining 10 kilos over 10 years if I'd known that now that I would have been much healthier position now and so just these subtle things of changing what that carbohydrate is can make a huge difference to people's lives so that's what my particular research is going for in the next next ten years now if all this has failed and you can't work out how to improve these these tablets might be the thing for you they're frozen poo tablets and you just have to about 15 of them and you get a total makeover all right AM the Americans call them craps eul's they're always very good with the short snappy phrases but they're no longer a laughing matter because they are the number one treatment for a very severe infection now called recurrent Clostridium difficile infection people have too many antibiotics get recurrent infections and they can die and people do die but this has a 90% success if you have a poo transplant from someone who's super healthy and you're in this and you're very sick ninety percent recovery which is three times better than the nearest current medical treatment it also works for our Steve colitis to the same extent as the latest drugs and it's being tried in a number of other conditions and so we know very little about it it's a very crude tool as you can imagine in more ways than one and everybody's different so clearly we may have to match donors and recipients in ways we hadn't thought about but they're using it for all kinds of interesting treatments including treating diabetes obesity etc so watch this space finally just to recap I think if you can think of your gut microbes in it with this gardening analogy you can't go far wrong you know it's a key aspect of nutrition you've got to realize that food is a series of chemicals it's not carbohydrates fat and protein and calories okay start thinking of these as chemicals that react with other microbes there to produce all this these chemical reactions which you need and everyone needs more fiber there's certain more polyphenols more fermented foods and we you need to explore also the reactions with medicines everybody reacts differently as with medicines as they do with the foods as well and so none of this is being tested by modern science yet we haven't caught up and really there's huge potential for personalized diets and the one message I wanna leave you with is is diversity diversity diversity the more you can do that the better and realize with a hundred trillion microbes inside you you will never truly dine alone again thank you [Applause]
