Can changing our gut bacteria change us?
Tuesday, March 13, 2018 - 20:30

According to the Gut Foundation, in the past 12 months around half the Australian population will have complained about some kind of digestive problem.  

Following the release of his book on the gut, Dr Michael Mosley returns to Insight for a discussion with fellow experts and ordinary Australians about how the gut can play an integral role in our overall physical and mental health.

We discover that improving the wellbeing of this unglamorous organ can have profound effects  – whether you have existing gut issues or not.

Increasingly, research is shedding light on the previously mysterious world of the gut and the 1-2 kilograms of microbes that live there, forming each person’s unique microbiome – the genetic ecosystem of bacteria, viruses, fungi and other organisms that lives inside and on our bodies from birth.

With more public attention to gut conditions such as Irritable Bowel  Syndrome and autoimmune diseases like Coeliac Disease and Inflammatory Bowel Diseases like Crohn’s or Ulcerative Colitis scientists are discovering how our microbiome plays an essential role in metabolism, nutrition, immune function and disease prevention.  We are also discovering its enemies – antibiotics, a lack of fibre and processed foods, to name a few. And as emerging research examines the link between the gut microbiome and how we metabolise our food, the precision in which we recommend diets could change the way we manage obesity and type-2 diabetes.

Our gut (and microbiome) is also connected to the brain, via over 100 million neurons (as many as you’d find in the brain of a cat) spread all the way from our throat to rectum – giving some credence to the old saying, “gut feeling”. It’s lead researchers to increasingly find links between our gut microbiome and things like our mood and food cravings, potentially spelling massive changes to how we approach treatment for depression and anxiety.

Already previously radical treatments like faecal matter transplants (FMT) are becoming common therapies for certain health issues – as Insight hears from guests who have undergone them.

Meanwhile, the efficacy of other medical aids for our gut – like probiotics – are being questioned we talk to medical researchers that are attempting to make them more effective and tailored to our unique microbiomes.

This week’s Insight tackles the ground-breaking science and personal stories around the gut’s potential to change our lives.

“Probing the world within our guts is changing our understanding of the way our bodies work,” writes Mosley. 




JENNY BROCKIE:  Welcome everyone, good to have you here tonight. Michael Mosley, you swallowed a pill camera so that you could see your gut in action.  Why did you want to do that? 

MICHAEL:  I thought it would be quite entertaining, I actually did it at the Science Museum in London so there was an audience a bit like this and, do you want to have a look at it? 

JENNY BROCKIE: Yeah, I'd love to have a look at it. 

MICHAEL:  It's been all the way through. It's well and truly cleaned up you'll be glad to know. 

JENNY BROCKIE:  Very glad to know that. 

MICHAEL:  And it is a marvellous technology because there it is. So you want to handle it? 

JENNY BROCKIE:  Okay. Yeah hold it up, yeah, yeah.  Maybe I won't handle it. I'll just have a look, okay. 

MICHAEL:  You can see there it's got a little bit there, it was flashing a light there and I had to swallow that, down the gullet, and then we followed the journey of the pill. 

JENNY BROCKIE:    There it is. 

MICHAEL:  There's a bit of porridge there, that white stuff.  I had a bit of porridge for breakfast.

JENNY BROCKIE:  How long was it inside you? 

MICHAEL:  About sixteen hours so we didn't hang around for the end. I am absolutely fascinated by the gut and so I wanted to do it and that's actually partly because of an Australian hero of mine called Barry Marshall who first introduced me to the microbiome and gut bacteria and things like that. 

JENNY BROCKIE:  Let's take a look of where that pill camera of yours would have travelled. 



The gut is also known as our digestive system. Starring roles go to the stomach, small and large intestines.  Digestion of food starts before it even reaches our stomach.  Our senses trigger the salivary glands into action, as we start chewing chemicals in saliva break down the food.

This is squeezed down the oesophagus when we swallow and heads towards our stomach. Here it's thrown around and mixed together with the help of our muscular stomach and chemical secretions.  The result is a creamy mush that heads into the small intestine.  Scientists call it cime.

The small intestine is the hardest worker of the gut and converts most food to smaller, easy to absorb chemicals.  Bile and enzymes break down the cime even further and tiny finger like villi absorb nutrients sending them to our blood stream. Resistant fibres that cannot be absorbed then move into the large intestine or colon.  This is where trillions of bacteria live and feed off leftovers. Anything that isn't absorbed is then excreted.


JENNY BROCKIE:  Now you describe those trillions of bacteria that live in our large intestine as the stars of the digestive system. Why? 

MICHAEL:  Because they are the most extraordinary creatures on earth in many ways. The bacteria, you know, there is more bacteria than almost anything else, apart from viruses on the planet, and they do a huge range of things. Bacteria can live on radioactive waste, it can live at the bottom of the ocean, but the ones in our gut are particularly good at doing to chemistry so they can convert the remains of the food which hit our large intestine into things which affect your brain, your mood, your weight and also your immune system. So for a long time we largely ignored them.  And it's only been in the last decade or so we've been able to understand what's been going on inside us. 

JENNY BROCKIE:  And we're only beginning to understand? 

MICHAEL:  Absolutely, 100 percent. 


MICHAEL:  This really is the beginning.  I imagine it's somehow, a bit like Galileo inverting the telescope. He looks up at the starry skies and suddenly he sees there is a vast universe out there that no one knew about before he did so, and that's the beginning of astronomy and in many ways we're sort of at that stage.  We know the microbiome is down there, we know it does an extraordinary range of complex things, and we're only just beginning to grasp some of the things it does. 

JENNY BROCKIE:  And the microbiome is the bacteria, it’s all this bacteria? 

MICHAEL:  It's the bacteria, the viruses, the fungi, there's a kind of rain forest down there and it's more complex than rain forest because there are probably 1,000 different species of different microbes down there.

JENNY BROCKIE:  Now those bacteria can be the stars? 


JENNY BROCKIE:  But they can also cause havoc? 

MICHAEL:  They can indeed because one of the new insights is the fact that we have what are known as old friends. These are the microbes that evolved with us over the last, you know, million years or so. But there are also microbes down there which are much less friendly than that and, you know, if you've ever had a gut infection, or something like that, or you've been unlucky enough to get cholera or typhoid, there are plenty of things which affect your gut really, really badly. 

JENNY BROCKIE:  Simone Langshaw in Victoria, your five year old son Darcy was born with an immune deficiency and he was prescribed multiple courses of antibiotics before his second birthday.  How did all of that affect him? 

SIMONE:   I guess ultimately the use of multiple doses of antibiotics led to him contracting a spore called clostridium difficile which then led on to him getting pseudo membraneous colitis and attacking his gut. So we sort of spent the next two to three years of his life fighting against that spore and trying to bring him back to, you know, a healthy state. 

JENNY BROCKIE:   What was going on with him physically while all this was happening? 

SIMONE:  Yeah, look, the clostridium difficile, or the C Diff as we called it, basically caused him to have severe, severe diarrhoea up to ten, twelve times a day which was associated with severe stomach cramps. He then contracted other infections on top of that, became very febrile, like very hot, and it was just a really nasty existence to be honest. He was a very miserable little boy. 

JENNY BROCKIE:  Sam Costello, you're a gastroenterologist and you treat C Diff, this condition, what is it? 

SAM: Clostridium difficile is a bacteria that can overgrow in the bowel when your native bacteria are depleted and that will often occur, as in the case with Darcy, after antibiotics. 

JENNY BROCKIE:  So it just goes berserk in the abdomen, healthy bacteria? 

SAM: When its competitors aren't there, and it causes diarrhoea predominantly and can also cause fever, abdominal pain and in some cases sepsis and can require, for instance, people to have their large bowel removed surgically. 

JENNY BROCKIE:  Simone, Darcy was given for targeted antibiotics to treat the C Diff, did they work? 

SIMONE:  Yeah, look we had a very, very long road with Darcy's C Diff.  He probably had C Diff on and off for nearly two years.  I think maybe we had five or six rounds of the antibiotic with again returning it, you know, still a positive C Diff result. So…

JENNY BROCKIE:  So none of the drugs were working? 

SIMONE:  His doctors that were treating him basically told us that he had failed medical, conventional medical treatment, there was no other treatment for him. 

JENNY BROCKIE:  And then Darcy's doctor suggested a treatment that had never been performed on a child in Australia before.  What was it? 

SIMONE:  Very blessed to have had a fantastic Professor looking after Darcy, Professor Katie Ellen at the Royal Children's Hospital in Melbourne, and she suggested to us that there had been some research based around a faecal microbial transplant and that it may be a viable for us. 

JENNY BROCKIE:  So that's actually transplanting somebody else's faeces into Darcy? 

SIMONE:  Yes, that's correct. So we actually underwent, you know, a very stringent screening process to find a donor which in the end was Darcy's father, my husband Ben, and yeah, that's absolutely what happened. 

JENNY BROCKIE:  Sam, how does that work? 

SAM: Well, it is fairly crude. We collect stool from a donor who is thoroughly screened for infections and other risks, and then it can be delivered in a number of ways. Either through the top end of the gut, so into the, into our stomach or small bowel via a nasal tube, or into the bowel, either by a colonoscopy or enema. 

JENNY BROCKIE:  And what's the thinking behind it?  What is the aim?  What does it do? 

SAM: The aim is to replace a more normal microbiome, a more normal ecosystem in the gut.

JENNY BROCKIE:  So it gets some other bacteria in there? 

SAM: That's right. 

JENNY BROCKIE:  That's going to do the job of fighting.

SAM: That’s right. Yeah. We don't know exactly how it works and there's a lot of components to stool other than bacteria that may play a role. 

JENNY BROCKIE:  Let's have a look at how Darcy's doing now. 



SIMONE: The FMT was nearly I guess instantaneous.  He came out of surgery and probably within twenty four hours we had a new child really. We noticed a change in his bowel action straight away which was essentially the main issue that we had. 

DARCY:  When I was little, yeah, well, they used dad's poo and they actually got some good bugs and put them into my tummy. 

SIMONE:  They did. 

DARCY:  To get the bad bugs. 

SIMONE:  You're a bit like Spiderman, I love it. 

SIMONE:  I think we were a bit taken aback that it worked so quickly and weren't sure whether it was going to last.  So eighteen months, nearly two years down the track and to have still no sign of the clostridium difficile and to have a healthy, happy boy, we're over the moon. 


JENNY BROCKIE:  Simone, what else did the faecal transplant help with for Darcy? 

SIMONE:  Yeah, look, surprisingly and obviously it was just an amazing bi product that we didn't anticipate, but Darcy also had multiple food protein intolerances at infancy.  So he was intolerant to an extensive number of foods. Post the FMT Darcy is now able to eat dairy and egg, soy, so many different things that he couldn't eat before. So I guess in terms of the food intolerances it's made a massive difference for him and his lifestyle and being able to eat like a normal little boy does. 

JENNY BROCKIE:  Michael Mosley, does that surprise you? 

MICHAEL:  Not at all because I've seen it done only in adults, and it absolutely remarkable that within twenty four hours people whose lives have been effectively destroyed because they have to spend all their life pretty much by a toilet or on the toilet, within, you know, literally a day, they are completely well and they stay completely well. And this…

JENNY BROCKIE:  Does it always work though? 

MICHAEL:  It's got a 97 percent success rate last statistic I saw. 


SAM: With a single treatment, around 90 percent effectiveness.  But if you continue to do the faecal transplant in those that fail, then you would approach 100 percent.

MICHAEL:  I mean this is as close to a medical miracle as you're going to get. I think you know, I actually spoke to a gastroenterologist who had first started doing it in the 1970's but had stopped because it was unethical. But it has, it is a remarkable, remarkable thing. 

JENNY BROCKIE:  And this is just for C Diff that we're talking about those statistics? 

SAM: That's right, that's for C Diff, yeah. 

MICHAEL:   I mean they are exploring other things because it is so extraordinary, but other things that have not proven, it's fair to say, isn't it? 


MALE:  Can I just say, this seems to have similarities, when our kids were small, we were told the mother koala actually feeds the little cubs her poo because when they're born they cannot actually digest eucalyptus. But she has to feed them her poo so they can pick up that bacteria. 

JENNY BROCKIE:   Andrew, you're nodding your head listening to that? 

ANDREW:  Yeah, yeah, that's one of the best known examples where you actually have deliberate transmission from a mother to infant of the microbiota and she actually produces a lovely little, it's almost a minty, it's a specially formed poo. 

JENNY BROCKIE:  The mothers should all be feeding their children poo. I think we need to kind of put the brake on this a little bit at this point. Jay, I wanted to ask you about faecal transplants because you had them as part of a clinical trial in 2014. Why? 

JAY:  I was diagnosed with ulcerative colitis.  It's a hideous disease.

JENNY BROCKIE:  Sam, can you tell us what it is a bit more precisely, ulcerative colitis, yeah? 

SAM: It's an inflammatory bowel disease where the body's immune system is attacking the bacteria within the gut and the bacterial lining is damaged in that process. 

JENNY BROCKIE:  So the lining of the large intestine? 

SAM: Of the large intestine. 

JENNY BROCKIE:  And what causes it? 

SAM: We don't really know, but there's a lot of research going into, into finding out that very, that very question. 

JENNY BROCKIE:  Jay, how was it affecting you? 

JAY:  Ah, well probably just before I started the FMT trial I was…

JENNY BROCKIE:  The transplant, yeah? 

JAY:  Yes, I was going to the bathroom up to forty times a day. 

JENNY BROCKIE:  Forty times a day? 

JAY:  Yeah. Some of the feelings that you can have of feeling, you know, feverish or cramps, but I think one of the hardest things is just the exhaustion, if you have children, and you're just absolutely depleted. 

JENNY BROCKIE:  Well just trying to live a life going to the bathroom forty times a day? 

JAY:  Or going to, work, you know if you're in a meeting it's very difficult to kind of excuse yourself up to ten times, yeah? 

JENNY BROCKIE:  And you were passing blood when you went to the toilet? 

JAY:  Lots of blood, lots of mucous. When I first started to get colitis symptoms I thought I was dying because of the amount of blood that I was passing.

JENNY BROCKIE:  What did your treatment involve with the transplant? 

JAY:  I was given frozen poo, essentially, from somebody else that I brought home.  It just kind of looks like a saline drip that you get in hospital and I would bring two weeks worth home with me to Newcastle, defrost one when I needed one every night and just give, it's essentially giving yourself an enema. 

JENNY BROCKIE:  And what happened? 

JAY:  So after it was probably took around three weeks for me to see any kind of difference and the first thing that happened was I stopped bleeding and that was great. I would have been happy just for that but then, and I passed a lot of mucous so that stopped too and I had my first solid bowel motion which was…

MICHAEL:  Hooray…

JENNY BROCKIE:  I like the way you, Michael, I really do. Had you tried other treatments? 

JAY:  Yeah, I'd tried lots of things and I was also quite nervous about some of the medications because of the side effects that come with them. 

JENNY BROCKIE:  What sort of things were the side effects? 

JAY:  Um, so some of them frightening ones I think are cancer, like bone density.

JENNY BROCKIE:  Not very attractive options? 

JAY:  No, not very. 

JENNY BROCKIE:  So a poo transplant by comparison looked pretty good, yeah? 

JAY:  Look, I know it sounds awful but when you're that sick, to have that hope that there might be something that will work, and then it does, you don't second guess it. If I could be getting it tomorrow I would be doing it.

JENNY BROCKIE:  Has that worked for you in the long term in if terms of your ulcerative colitis? 

JAY:  I went straight into remission for eighteen months after my FMT trial, which was really fantastic, and then I unfortunately got a bowel infection after that at some point.  So what I decided to do from there was to just continue on doing FMT myself at home and that put me into remission again. 

JENNY BROCKIE:  And what's happened now? 

JAY:  Well unfortunately again in April I got another bowel infection, I went into hospital and I've just, with work commitments at the minute, I've submitted to medication. 

JENNY BROCKIE:  And is that helping? 

JAY:  It certainly has helped this time, but unfortunately like I said before, there's certain side effects to that.

JENNY BROCKIE:  Sam, we've talked about C Diff and the very high success rate with that, but is there solid evidence that these transplants work for other things like ulcerative colitis? 

SAM: So there are four studies now looking at ulcerative colitis and induction of remission, and overall, there is evidence that you can induce remission with faecal transplant.

JENNY BROCKIE:  And what sort of percentages are we're talking about of people who going into remission? 

SAM: Roughly 30 percent.

JENNY BROCKIE:  Do you know why these transplants work? 

SAM: No, no, certainly not for ulcerative colitis. I mean we have some theories, we do think that the bacteria involved in the process and the immune system and the interaction there, and so by changing the bacteria then perhaps those aberrant processes that are going on may also change. 

JENNY BROCKIE:  So do you know which bacteria people need? Do you know what to get?  You know, what kind of poo to get? 

SAM: No.  We don't know that and we don't even know if it is actually the bacteria. There might be other parts of the…

JENNY BROCKIE:  Elements, so it really is very experimental? 

SAM: Yes. 

JENNY BROCKIE:  In that sense? 

SAM: Yes, and these studies have samples taken, so stool samples and other samples that are being analysed to try and work that out. 

JENNY BROCKIE:  Are there risks in transplanting someone else's faeces into your body? 

SAM: Yes, theoretical risks. The faecal transplant, although first performed in the 1950's, has really only been performed in large numbers in the last say five to ten years at the most, and so we don't have long terms data, so it's important to say that.

JENNY BROCKIE:  Michael, your response? 

MICHAEL:  No, I think it's absolutely fabulous I must admit. I mean it is about the safest, it’s not completely safe and I wouldn't recommend, people do do it at home, I absolutely wouldn't recommend it, doing it at home, and there are exploring its use in other things as well, including obesity, type 2 diabetes and strangely enough autism, but these are very early stage experiments. But I do think it is wonderful because it is so simple at some level and it is so basic, and yet it's so amazingly effective, certainly for some conditions. 

JENNY BROCKIE:  A lot of people have gut problems of one kind or enough. You say we've decimated our guts.  How? 

MICHAEL:  I think that this has partly happened, there's a widespread use of antibiotics.  I mean clearly we need to have antibiotics, particularly, you know, if you have a life threatening condition. The problem is that we consume them by the handful and have done so historically. People are now much more cautious of doing so because of resistance but also we're becoming increasingly aware that they can have lot term consequences on the gut. 

And there also evidence that we eat a smaller range of foods. And the other thing we've done is that we eat a lot more processed food and processed food is generally not terribly good for the gut. So on the one hand we haven't been feeding it with the good stuff, on the other hand we've been feeding it with lots of bad stuff. 

JENNY BROCKIE:  What about probiotics, can they do the job of fixing the balance in the gut? 

MICHAEL:  Well that's really interesting and really, really early research as well. So we know there are these sort of probiotics, if you like, which are the good bacteria that you can consume in foods and you can also get them this pill forms. I've seen quite a few trials for different conditions.  I don't think there's any evidence that one particular pill is going to cure everything, but when it comes to things like diarrhoea or IBS, there is some evidence that certain types of probiotics may prove to be helpful. So this is again very, very early research but absolutely fascinating.

JENNY BROCKIE:  How many people have taken a probiotic in this room? Oh, my goodness, look at you all. Jo, you've taken them? 

JO:  Yes. 

JENNY BROCKIE:  Did they work for you? 

JO:  Not really. I didn't see any difference. 

JENNY BROCKIE:  Milena, what about you? 

MILENA:  I took a set of probiotics which I ordered from a microbiologist for about six months.  They didn't have any effect but at the same time I was taking vancomycin and rifaximin as well so perhaps that was why, yeah. 

JENNY BROCKIE:  How many people would say that they found probiotics useful out of those of you who?  Oh, very small number compared to the number that put up their hands, that's interesting. Andrew, you're a microbiologist, do you think it's worth spending money on probiotics? 

ANDREW:  So probiotics are going to be useful where you're actually missing the specific benefit that that particular probiotic is going to take back. So if that is the nature of your problem, then the probiotic has a good chance of helping, but if you were reasonably healthy in that respect to start with, then it's not going to particularly help.

JENNY BROCKIE:  Well, if there are what, trillions of bugs in your stomach, I mean how are you to know which ones are going to work and which ones aren't? 

ANDREW:  Yeah, I often use the analogy of it's an ecosystem, Michael mentioned the rain forest before, restoring a rain forest with probiotics is a bit like saying you're restoring a rain forest with a packet of grass seed.  That you're taking just one thing that you think is useful and adding in and hoping to restore a complex system. It might work and there are some cases where it has been shown to work, but it's not going to be generally applicable all the time. 

JENNY BROCKIE:  So what do we actually know for sure about how the gut affects our health, in terms of where the research is up to? 

MICHAEL:  I think where it's up to is that you want as diverse a microbiome as possible. As wide a different range of bugs down there because it's quite good to say this bug is good and that bug is bad because the reality is that you want a range. You know, we like elephants but if the whole planet was covered by elephants this wouldn't be a terribly good thing for the planet.  

So you need these things in for a broadly good ratio, and one of the things that's become very clear is that an awful lot of diseases like ulcerative colitis, like Crohn's and things like asthma and other conditions which are effectively the body attacking itself. These seem to be fairly dramatically on the rise over the last fifty years or so and that may well be to do with the fact that our guts are not as full of lovely microbes, or the right sort of microbes and they once were. 

ANDREW:  If I could add to that, it really is a cross talk between the body system and the microbes.  So it doesn't mean a lot to talk about good bugs and bad bugs in isolation, it's how the bugs are working with us. 

JENNY BROCKIE:  Interacting? 

ANDREW:  Yeah.



Humans are made up of bacteria and cells. The trillions of bacteria that live in and around our bodies is called the microbiome. We all develop different microbial communities depending on our genes, diets and the other bacteria we come into contact with.

Over 95 percent of our bacteria live in our gut, mainly the large intestine.  The more diverse the bacteria, the better it is for our health. Together they help regulate our immune system and weight and can possibly affect our mood and we're still finding out what all of them do and how they do it.

To feed our gut microbiome we need to eat the kind of food that ends up in our large intestine, lots of processed for or sugary foods are absorbed before getting there and if we're not feeding our microbes or we have too many doses of antibiotics, our ecosystem becomes less diverse. Not all bacteria process food the same way. Some people have bacteria that make it harder to lose weight, but that doesn't mean you've got no hope. There are ways to change what lives in your gut. 


JENNY BROCKIE:  Michael Mosley, how can you change what lives in your gut? 

MICHAEL:  Primarily by changing what you eat and your microbiome is to some extent settled in the first three years of life, and broadly speaking you inherit it from your mum.  But later in life you can change it. They've done some interesting studies where they get people to swap diets and they take poo samples and they find that if you switch from a classic western diet, which is high in fat and sugar, to one which is high in fibre, then quite rapidly you see a change in the microbiome. 

JENNY BROCKIE:  And what's important is what makes it to the bottom of your gut? 


JENNY BROCKIE:  To your large intestine? 

MICHAEL:  It is, and what you're feeding down there because there are lots of foods which obviously get absorbed in the small intestine but there are foods, particularly those which are rich in fibre, which provide the nutrients that those lovely little microbes need. 

JENNY BROCKIE:  Have scientists described what an ideal gut looks like, what a healthy gut looks like? 

MICHAEL:  I think probably not. Diversity seems to be one of the critical things. They have studied, for example, the Hadza who are hunter gatherers and they seems to have a particularly diverse biome. There is a microbiome researcher who very bravely decided he wanted to acquire one of the best biomes on the planet so there's a picture of him sitting upside down under with a tree with a funnel in his bottom and they're pouring in heads of poo. I don't think that worked out so well but I think I would rather go for the food rather than that approach. 

JENNY BROCKIE:  And did they work out why these particular people had very healthy guts? 

MICHAEL:  It's a combination of things. It is a combination of the foods they eat, the fact that particularly with Hadza they practice a form of intermittent fasting where they go for quite long periods without food if necessary, and also the fact that they do quite a lot of exercise. We're not clear the entire relationship between exercise and the biome, but like everything else, exercise seems to be jolly good for those little microbes. 

JENNY BROCKIE:  You do like intermittent fasting? 

MICHAEL:  I love intermittent fasting and I was thrilled beyond belief when I discovered it had such a positive effect, biome. 

ANDREW:  Is that intermittent fasting just known as a failed hunting trip? 

MICHAEL:  It could be indeed. I think it's mainly not snacking is the secret. 

JENNY BROCKIE:  Do we know what all those bacteria do? 

MICHAEL:  No, I think we have hardly a clue. The good ones if you like, what they do is they tend to produce substances which are, you know, short chain fatty acids which calm the gut in various places, which reinforce the wall of the gut because somebody was saying earlier your gut is lined with sort of snot with mucous and that helps keep the gut wall intact.

JENNY BROCKIE:  You had your faeces tested? 

MICHAEL:  Many times. 

JENNY BROCKIE:  To find out what bacteria is living in your gut? 

MICHAEL:  Yes, I did. 

JENNY BROCKIE:  Now you place a great priority on diet. What did you find? 

MICHAEL:  I thought it was in decent shape bit it could be better, to be honest.  Clare my wife over here had frankly a better, better mix of gut bacteria than I do. 

JENNY BROCKIE:  And is that because of what you eat, or is that because of your make up? 

MICHAEL:  Combination I would suspect. I'm absolutely certain genetics plays a role because genetics always plays a role.   But one of the things I discovered was when I changed my diet and I started to eat far more of the sort of foods you see there, it moved in a very positive direction.

JENNY BROCKIE:  Kate, tell us about your diet? 

KATE:  My diet, during the day when I go to work I'll have toast in the morning, I'll eat avocado and smoked salmon, I'll have salad for lunch, I'll eat that with tuna, I try and eat mixed nuts, I eat fruit as well but at dinner time I usually make quite kid friendly dinners like spaghetti bolognaise and quiche and those kind of things. 

JENNY BROCKIE:  And you've been trying to lose weight? 

KATE:  I have so I've been running, so I have been trying to lose weight, and I've been trying to add bacteria to my gut. 

JENNY BROCKIE:  So what sort of things? 

KATE:  So I have been making cobulture and I've been making kimchi so the hope to improve that. 

JENNY BROCKIE:  So this is fermented tea and fermented vegetables? 

KATE:  That's right. 

JENNY BROCKIE:  And has it worked? I mean…

KATE:  I feel better but I can't tell because I'm running, so I can't tell if it's the running or it's my diet that's making me feel better. 

JENNY BROCKIE:  And what about weight loss? 

KATE:  It's been quite slow, so I've lost about 4 kilos since the New Year, and I'm just wondering if I have some kind of insulin resistance or something like that. 

JENNY BROCKIE:  Do you have gut problems? 

KATE:  I do have slight gut problems, yes. 

JENNY BROCKIE:  What does that mean, what's a slight gut problem? 

KATE:  It means that I, I don't form poos. 


KATE:  No. 

JENNY BROCKIE:  What, you don't form a solid stool? 

KATE: No, and I haven't for many years. 


KATE:  Ten years probably, mm-mmm. 

JENNY BROCKIE:  And now Phil, you've lab tested a faecal sample of Kate's? 

PHIL:  Mm-mmm. 

JENNY BROCKIE:  How did you do that? 

PHIL:  Um, well, we sent Kate a swab to swab a bit of her poo in the privacy of her own home and then we extract the total DNA from that sample, from that swab, and then we sequence it. So that basically gives us the blueprints of the organisms in Kate's gut and so…

JENNY BROCKIE:  And you're comparing that to other samples that you're taking? 

PHIL:  Yeah.  So we're doing genome sequencing, so a lot of the commercial offerings at the moment are just sequencing one gene and that gene tells you who is there but it doesn't tell you what they do. So if you sequence the whole genome you have the blue prints of the organism, then you can start to work out does this thing produce, have this capacity to make anti-inflammatory compounds, can it make Butyrate or Faxanadu or short chain fatty acids. 

JENNY BROCKIE:  Andrew, you've read Kate's results, what do they tell you about her gut health? 

ANDREW:  She had a number of organisms that were quite unusual, that aren't frequently seen, Phil may want to say a little bit more about these, but when you have someone who's got a, she's had a problem with not forming stools for a long period of time.  There's no obvious pathogen in there so you look for these indicators that are known to cause that sort of problem. If you don't see one of them, then that becomes the little detective work starts and you say well, that's then a candidate, maybe that's what's unusual here and so that's when you would start to look more widely and say well, there are other people who've got these symptoms have as well.

JENNY BROCKIE:  Because on the face of it, her diet on the face of it looks fine? 

ANDREW:  Yes. 

JENNY BROCKIE:  It's not so though she's eating badly or, you know, has great, do you? I mean it doesn't sound like…

KATE:  No, I think I try hard to eat well. 

MICHAEL:  Did you any course of antibiotics either in your youth or more recently? 

KATE:  I've had operations and I think they would have given me antibiotics at the time of those operations. 

MICHAEL:  Yes, because antibiotics seem to have a more devastating effect on some people than others. Some people recover very fast, other people take months, years, decades, not at all. 

JENNY BROCKIE:  Matthew, you're Kate's husband, do you have a similar diet to her? 

MATTHEW:  In the morning, yes, and probably the evening meal will be the same because we eat as a family. But during the day my diet is poor.

JENNY BROCKIE:  What sort of things, just to give us examples? 

MATTHEW:  Oh, a sausage roll and a sandwich, unfortunately a KFC or a McDonald's because it's there, which is bad, and I've never been a lover of vegetables and fruit and that's from my youth as well. So yeah, in terms of…

JENNY BROCKIE:  Now you got tested as well? 

MATTHEW:  Yes, yes. 

JENNY BROCKIE:  And Andrew, you've seen Matthew's results, how do they compare to Kate? 

ANDREW:  So we talked a little bit before about needing to have the fibre, basically to feed the bacteria in your colon and essentially your diet is one where you've got a lot of processed foods and so your diet sounds like it's one that's characteristic of starving, or at least limiting that part of your microbes, that are producing short chain fatty acids is a term you'll hear again and again, and in particular Butyrate is a really important one. 

JENNY BROCKIE:  Okay, what do these things mean? 

ANDREW:  Essentially bacteria have to poo too. So after they've eaten the waste that they pump out is actually stuff that we can use and so these short chain fatty acids are bacterial poo, or what they excrete. But there's still quite a lot of energy and nutritional value in those short chain fatty acids and our body uses that for a number of purposes but there's a group of the known Butyrate producers that are amongst the most decreased in Matthew's microbiota which suggests that he's not adequately supporting those bugs that are most wanting to desperately cooperate with you. 

JENNY BROCKIE:  And what are the implications of that for him and his health? 

ANDREW:  Well clearly not dramatic in the short terms because he's basically healthy. 


ANDREW:  Here, yes. The real shift that we've seen in modern societies is an increase in these chronic diseases.  So these are things that accumulate their impact over time and so your lifetime risk of developing a number of sorts of, type 2 diabetes, obesity are the obvious sort of ones but you could add in the inflammatory bowel diseases as well, will basically increase the longer that you're essentially starving that aspect of your relationship with your microbiome. 

JENNY BROCKIE:  Having any second thoughts about what you eat now? 

MATTHEW:  Yes, I do get reminded on a regular basis. 

JENNY BROCKIE:  Just checking, just checking. Could Kate's gut bacteria be the reason she's not losing more weight, even though she says she's eating quite healthily and exercising? 

ANDREW:  They could be a factor, in factor more than likely are a contributing factor, but this is getting back to that point where we really shouldn't be blaming the gut bugs for everything. 

JENNY BROCKIE:  Or leaping ahead of ourselves? 


JENNY BROCKIE:  And it could be genes as well? 

MICHAEL:  Genes always play a part in everything, don't they? Yeah. 

JENNY BROCKIE:  Mm-mmm. Michael, you're best known for your 5/2 diet which is based on intermittent fasting. Can you come up here and show us what you've added to your diet since you became interested in the gut? 

MICHAEL:  Absolutely.   So what's really interesting if you look at this stuff and you think to yourself, okay, I knew this already, these foods are supposed to be good for me, there's lots of vegies here and I know vegies are good for but I just can't bring myself to eat them.

JENNY BROCKIE:  But just to get onto the change, I'm interested in the change in terms of the gut and what we know about the gut. What are the things now that you think are important to be putting into your body? 

MICHAEL:  Right. Lots and lots of different things, but mainly it's feeding, if you like, the diversity of the microbiome that you want down there. What these foods have in common is that most of them, not all of them by most of them have a quite a lot of fibre in them, and they have the sort of fibre which the microbes like to digest. 

JENNY BROCKIE:  Well the lentils have a lot of fibre in them? 

MICHAEL:  They do. You should be aiming at around 25 grams of fibre a day and most Australians are probably less than half that, and I suspect you're probably closer to four or five. 

JENNY BROCKIE:  I was interested when I saw that there was pasta and rice here because I know that you're not a big fan of these things in terms of their…

MICHAEL:  I'm not. I think that on the whole, particularly the white stuff, that we've been sold the idea we should eats lots of it.  Now people are going, you know, low carb.  I think there are lots of different kinds of carb, these are all good carbs, you know you need carbs in your diet but mainly in the form of these sort of foods over here.  This stuff not so much and …

JENNY BROCKIE:  But, there's a but? 

MICHAEL:  There is a but.  On an episode of Trust me I'm a Doctor, we decided to test this idea of resistant starch.  Resistant starch is basically a form of food which is a starch, this is a starch, but which is transformed into something which is much more like fibre. So we did an experiment where we took pasta and we got a bunch of Italians to scoff it and then we measured their blood sugar levels, and then what we did is we cooked it, we cooled it and then we heated it and we assumed that reheating it would make it less resistant, actually made it much, much more resistant. 

JENNY BROCKIE:  And what's the advantage of it being more resistant, it goes to the lower intestine.

MICHAEL:  You poo out more of it. Your bugs get more of it. It's more like fibre and you get much smaller sugar peak. 

JENNY BROCKIE:  What about these fermented things? 

MICHAEL:  Fermented is something I'd never ever dreamt that I would enthuse about because it's quite an acquired taste initially. But yeah…

JENNY BROCKIE:  This is kombucha, yeah? 

MICHAEL:  This is kombucha, yeah, and I actually really, really like kombucha now. 

JENNY BROCKIE:  Which is fermented tea? 

MICHAEL:  It is absolutely, and you can make it yourself and indeed we did a small study where we got samples of sauerkraut and kombucha and sent them off to be analysed by scientists and less than half of the commercial versions were growing anything.  Doesn't mean they weren't bad because they could have had all sorts of metabolites, but this stuff is actually…

JENNY BROCKIE:  Do you want to have some? 

MICHAEL:  I would love some. I've actually acquired a strong taste for this. 

JENNY BROCKIE:  There you go. 

MICHAEL:  I prefer it with a bit of fizzy water because undiluted it's quite strong. 

JENNY BROCKIE:  So what does it do? What do fermented things do?  Like we've got sauerkraut here as well. 

MICHAEL:  That is really good. There are lots and lots of good microbes in the fermented things and I also just like the flavour. It just, you know, it makes your taste buds sing. 

JENNY BROCKIE:  So we've got other things, we'll run through a few things, we've got turmeric here? 


JENNY BROCKIE:  We've got chick peas and humus here.  Meat? 

MICHAEL:  Meat, you know, I like red meat, I have it a couple of times a week, I aim broadly for around 100 grams, 100 grams is the magic…

JENNY BROCKIE:  So about that the size of one of those? 

MICHAEL:  Yeah. Processed meat not so good for you but red meat, a good source of iron, particularly if you're a menstruating woman, that is quite difficult to get adequate sources of iron and therefore there are an awful lot of menstruating women who have anaemia of some form or another. They may or may not know it.  I think if you eat a lot of it it's bad for you. I think modest amounts are pretty good. 

JENNY BROCKIE:  And why green bananas? 

MICHAEL:  Green bananas, because they're rich in resistant starch, much more so than yellow bananas and this again…

JENNY BROCKIE:  But they're crunchy?

MICHAEL:  They're crunchy, absolutely, but they have probably three to four times more resistant starch per gram than, I like again the flavour. 

JENNY BROCKIE:  My mother used to always say that you get a pain in your stomach if you ate a green banana? 

MICHAEL:  I'm afraid your mother may have been wrong. 

JENNY BROCKIE:  Not true? 

MICHAEL: No, no, no, depends I guess how many of them you eat?

JENNY BROCKIE:  Yes, okay, I'm very pleased to see red wine and chocolate on this table. 

MICHAEL:  Yes, indeed. 

JENNY BROCKIE:  Can you explain to me why? 

MICHAEL:  Sure. Probably because they have flavonoids and other substances in it and what is another characteristic of this, this is broadly what I would describe as a Mediterranean diet, it's one which had lots of vegies in it, it has fish in it, it's got whole grains in it and indeed a glass of red wine, but probably not much more than a red wine with the evening meal. 

JENNY BROCKIE:  And the chocolate? 

MICHAEL:  Chocolate, dark chocolate, that's got, it's quite rich in antioxidants and flavonoids.  Cocoa is itself good, pretty good anyway, it's when you throw in lots of sugar and milk that it becomes not so wonderful. Also much less addictive I have to say. 

JENNY BROCKIE:  And just finally bread okay? 

MICHAEL:  Yeah, bread. You know, I mean I try and, I don't eat too much of it these days because I…

JENNY BROCKIE:  Well you didn't like it very much when you wrote your 5/2 book? 

MICHAEL:  I think the problem with bread is once you start on one slice, you eat the next one, and for breakfast I would much rather have eggs. Eggs fill me up. If I, you know, you can have a couple of scrambled eggs with some smoked salmon, or you can have two slices of toast with a pile of marmalade and one is best if you want to keep you full, it's going to give you very low peak. The other one is going to leave you starving hungry at about 11 in the morning so yeah. 

JENNY BROCKIE:  Andrew, you've recently published research on mice that recommends a high complex carbohydrate diet and a low protein diet. Why? 

ANDREW:  What we were wanting to get at is what are the different dimensions of diet that actually drive both the microbiota but also how the whole body system responds because you can't really look at things in isolation. If you talk about a high fat diet when you've increased that fat content you've also decreased the protein and carbohydrate content so you don't know which of those three changes has driven the outcome. 

JENNY BROCKIE:  And people get very confused by all this? 

ANDREW:  Yeah, and you wonder well why is it that the 5/2 can do the same thing for you as a Mediterranean diet?  Does it really matter what you eat? Well one of the things that came out of that study is that one of the driving mechanisms here seems to be creating a situation where the microbes are forced to cooperate with us in order for the food to deliver its benefit. So a high fibre diet is basically giving the microbes a carbon source, to use the technical term, but they can't grow on carbon alone.  They also need other nutrients, in particular nitrogen, and that part they get from us. So they have to cooperate and that promotes a beneficial outcome.

The 5/2 strategy appears to do the same sort of thing. On those days when you're fasting there's no food coming in for the microbes and so they have to cooperate with us to survive through the gap and so again you're promoting a cooperative interaction which promotes intestinal health.  And the last part of that little story is that it's not so much carbs as being bad, or even the type of carbs as being bad, it's the ratio of the protein to the carbohydrate in the diet that most dramatically shapes how the microbes are going to be operating. So distribution…

JENNY BROCKIE:  So what ratios are you talking about as good and what are bad? 

ANDREW:  So a relatively low ratio of protein to carbohydrate, and in particular the ratio of protein to the type of carbohydrate that actually makes it down to the colon. 

JENNY BROCKIE:  So that's vegetables a lot of the time? 

ANDREW:  Yes. It's vegetables it can be equally be resistant starch. 

JENNY BROCKIE:  So the heat, cool, heat pasta and rice? 

ANDREW:  Yes, and whole foods are good not just because of the type of fibre but also because of the native structure of the food is still there.  Hands up who's a pea appear in their poo? Yeah! So…

MICHAEL:  Many times. 

ANDREW:  It's basically a slow release form so the actual structure of the food, not just what chemicals are in it, impacts how it's delivered. 

JENNY BROCKIE:  So how applicable are these principles to everybody?  I mean is everybody going to react the same way to these things? 

MICHAEL:  Probably not, but on the whole if you were actually looking for a scientifically studied diet which is seen to be extremely healthy, then you would choose the Mediterranean diet, and I do not mean one which is rich in pizza and pasta but one which has whole grain vegetables, oily fish, as I said a little bit of red wine, it's got yoghurt, it's got seeds, it’s really tasty, and then you throw in some of the best of the Asian. 

You know, you have a bit of seaweed, you also have a bit of the fermented foods, a bit of East European, and there are all these sort of really excellent ways of doing so because I think people don't really think that much in terms of, people became obsessed by fat to carbs ratio and, as you were saying, it's really not about that. I'm also not a huge fan of very high protein diets because I think the evidence is quite strong now that is not a very healthy way to go. So if I was a having a meal and, you know, I might have a bit of steak or probably a bit of fish and I would have a big pile of veg and I would probably have much less of the potato and the stuff like that. 

JENNY BROCKIE:  But my question is more is everyone going to react the same way? Like because that's what I'm fascinated by, where some of this research is going too.  That you know, if I eat these things am I going to have the same reaction as if you eat these things? 

MICHAEL:  Almost certainly not. I mean interestingly the University of Sydney created, I believe, the GI index, the glycaemic index which is the response that your body has to food, how much of your blood sugars surge. But we know because of work in Israel where they put blood monitors on about a thousand people and followed them that we all respond differently.




ERAN:  This large scale research job was performed in joint collaboration between my lab and the lab of my good friend and colleague, Arold Sigal, also from the Weizmann Institute of Science.  Each of the participants basically had to give us a week of his or her life and for example, Jotham was one of our 1,000 participants, was connected to a continuous glucose monitor that measured his blood sugar levels every five minutes for an entire week.

JOTHAM:  And then they downloaded a smart phone app to our phone, that was probably the thing that consumed most of my time. Everything that I ate, every physical activity I had to document.

ERAN:  And you gave us a microbiome?

JOTHAM:  Yes, and I gave a microbiome sample.  Do you want more details of that?

ERAN: Each individual featured a large number of surprises. In my particular case I discovered that I don't spike my sugar levels when I eat ice cream, in contrast when I ate bread my blood sugar levels spiked through the roof so I really cut down on my bread.

We found out that each person reacts uniquely and differently, even when they're given identical food. So even when we gave 1,000 people an identical piece of white bread, their blood sugar level responses were very unique and this led us to take this personalised data and devise a machine learning algorithm which allows us to predict in a very accurate manner how each individual would react to each different food that that individual intends to eat.

We found that the gut microbe, their composition and their function, are very important in determining each person's individualised response to any given food.

JOTHAM:  The greatest thing for me, the thing that's caused no response whatsoever was chocolate, but that was great although I didn't need a Yael and Rami to tell me I can eat as much chocolate as I want. 


JENNY BROCKIE:  Lucky man. Andrew Holmes, you're familiar with this Israeli research.  Might it mean that each of us needs a personalised diet, a very personalised diet, that general rules about food might not apply to everybody? 

ANDREW:  Yeah, so this was one of the most exciting things to come out in the last couple of years in the field because, as you just heard from them there, that they showed two things. One is that each person reacts differently in terms of their glycaemic response, but what wasn't emphasised there was each person also reacts predictably. So when they took the same person and measured them on a couple of different days, they got very much the same sort of response.

So that straight away tells you that you can't predict someone's glycaemic response just from what they eat, there are other things about their body system that's also dictating that. And the machine learning is a fancy sort of way of saying we get a machine to look at everything, work out a pattern and then make a prediction.

But that prediction is only going to be as good as the data set that you trained on, so this is where the excitement is coming for the future, I guess, that expanding the size of the training data sets and getting some mechanistic understanding of what exactly is driving that will get us to the point where we can, as you put in, personalise diets to get the target response for people.

JENNY BROCKIE:  There's a lot to look at here. I mean to get a personalised diet you'd presumably have to know your reaction to a huge range of foods? 

ANDREW:  Yeah, yeah. 

JENNY BROCKIE:  And also know exactly what is in your gut in terms of the bacteria? 

ANDREW:  You need to know what's in your gut in terms of the bacteria, so this is the real value of those tests. If you also know what the person is eating and you know how they typically respond to those foods, as was done with the Israeli study, then you can put those three things together to get a predictive model. The interesting thing is if just look at one of them in isolation, you don't get a terribly reproducible answer. 

JENNY BROCKIE:  So how far off is that?  You know, how far off is it for me to go to the doctor and say just map me, just, just you know, just work out for me all the things that are fine for me to eat and all the things that my gut's going to have a good reaction to and a bad reaction to so I can form a diet around those things? 

ANDREW:  It will vary for conditions so we can see that for blood glucose response, there's been tremendous advances there.  So we can probably expect some form of reliable prediction there within the next few years, I suspect. So I think that we're going to see this increasingly coming in for all sorts of different conditions.  

JENNY BROCKIE:  Soon though? Michael, what do you think?

MICHAEL:  I think it's really interesting. I mean I've interviewed the Israelis when I was writing my book and I just thought it blew me away, really, really interesting, and they are pushing on now, as I said they are testing prediabetics, diabetics, and the great things is with their particular algorithm is they say you don't, they don't need to test you for all these foods.  They can actually, based on your poo sample and a few other things, they can predict with a fair degree of accuracy how you will respond to a particular food without having to measure your blood sugar levels or things like that. So that's really interesting. So even that said, I would say on the whole, ice cream is not terribly good for you, even if it's not pumping up your blood sugar levels probably doing other things like, you know, a spare tyre is inflating. 

JENNY BROCKIE:  Obesity and type 2 diabetes are massive health issues in Australia, in many other parts of the world. Might the gut play a really crucial role in addressing those conditions? 

MICHAEL:  I think almost certainly that the gut and inflammation in the gut, and then you get a generalised inflammation and that almost certainly contributes to things like obesity and type 2 diabetes.  What is really interesting is the sort of foods which are good for your gut biome which are the Mediterranean style diet and some of those eastern foods, if you like, Asian foods.  They also tend to be associated with slimness, they are the sort of foods which if you eat them, you're less likely to put on weight. 

So things like olive oil, fish, they're kind of good for your biome but also good for you and it could be that part of the reason they're doing all this good is because they're affecting the biome, but I suspect it's a multi system approach. But the good news is the bugs, you know, the old friends down there that you want to encourage are tasty, interesting, varied food is the way to go. It's good for them, it's good for you and we've been talking about cooperation and I think that's what it's about. You've got to cooperate with your old friends, you've got to invite them around to dinner, you've got to feed them well, got to look after them, got to massage them, be kind to them and they'll be kind to you. 

JENNY BROCKIE:  Great note to end on. Thank you so much for joining us tonight. It's been a fascinating conversation, we should get together again in about five years and see where we're up to.  And that is all we have time for here but let's keep talking on Twitter and on Facebook. Thanks everyone, thank you.