THE MICROBIOME SUMMIT : Love Your Microbiome
History of the FODMAP Diet
Dr. Peter Gibson, MD
Dr. Peter Gibson is a gastroenterologist who took a risk and chose to focus his attention on the role of diet in GI disorders. Listening to his patients and understanding that there has been evidence over the last 40 years that diet can affect symptoms he went on to develop with his colleagues the FODMAP hypothesis back in 2004. Since then he and his colleagues have diligently researched, organized and championed a diet for those with functional bowel disorders like Irritable Bowel Syndrome (IBS). It has been a savior to many and given sufferers their lives back. In this interview, Dr. Gibson provides us with the origins of the FODMAP diet. Dr. Gibson will also provide insight into future holistic work in the treatment of functional bowel disorders, including biofeedback and gut-directed hypnotherapy tapping into the gut-brain axis.
- Tracey:
- Okay. We are here with Dr. Peter Gibson from Monash University in Melbourne Australia, he is also with the Alfred hospital. Dr. Gibson is one of the creators, the leader of creating the FODMAP diet and he is here today to give us a bit of a history lesson on how this was, how this came to be. Welcome Peter.
- Peter:
- Thank you. Well it was interesting as a young gastroenterologist we always struggled with, how to manage people with irritable bowel syndrome and diet was just a little side issue that, you would change people’s fiber, you would reduce their lactose in their diet if they had hyper lactasia but we really didn’t make much of an impact and so diet was never unimportant part. However what we did was, we knew that lactose cause symptoms like IBS in people who can’t digest it. We knew that there was data on the fructose, when you have it in excess of glucose, that it caused problems. There was data that fructo-oligosaccharides or fructans and galacto-oligosaccharides were well known to cause problems such as the baked beans and the bloating and wind that that causes. And then the penny really dropped, we said well if one of them alone doesn’t do it what about if we combine them all because they all have very similar modes of action. And then the secret was if we start talking about this we need a word for it in the competition in our department, FODMAP one and it stuck. We are told that it was an ugly word but people remembered it. So the low FODMAP diet then went through a series of studies, first was to determine whether our mechanisms of action, we thought were happening, was true. In other words increased distention of the bowel with water and gas. Secondly we then went ahead to do some efficacy studies and it was very important that with our infrastructure, we can feed people food for, two, three, four weeks and we can blind the food and what we did is we got people and we did a crossover study where we gave them a low FODMAP or a sort of a usual Australian diet, FODMAP diet, and found that there was big differences between the groups with the low FODMAP diet reducing symptoms significantly. In probably about 70% of people which was in fact our clinical experience. So then the aim then was to actually implement the diet and the way to do that was to not only publish papers on it and to gain, collaborations around the world where people at King’s College in London for instance took this up very early. People in Christchurch in New Zealand took it up very early and gave us some data which was similar to ours. And also did some very nice controlled trials. So what we had was the evidence, and with medicine doctors don’t change practice without evidence and what then happened was that there was some doctors who said, we will give this a go and found that people were improving. And then it became that the people told people, people talked to their doctor, their doctor learned about it and by word-of-mouth really and by experience, things seem to spread. The other thing that has been of great help is the fact that we have been able to get accurate information out around the world about it via the app which can be updated so the history of it is really quite interesting how from ideas 12 years ago now it is being used as a primary therapy in many countries and it is being used in most countries around the world at least by a proportion of people. What it has done however, I think even more importantly what it has done is that it shows doctors that diet is a powerful tool. We have always known that it’s a powerful tool for celiac disease but for irritable bowel syndrome it is a very powerful stool and it enables us to get much better benefit in symptom resolution in patients then what we were able to achieve before. Now what has happened is a very large push to find diets for inflammatory bowel disease that are going to help inflammation. Which the FODMAP diet is not meant to do. And doesn’t do that. So that I think that there is a new fervor in the medical community or the gastroenterological community to find dietary therapies just as there is in the community because you know the community is very keen to find diets, dietary things because it’s one way that a patient can influence their sense of wellness, influence their symptoms, that they can do. Rather than wait for the doctor to give them a pill or something else.
- Tracey:
- Right. Did you get any pushback from the gastroenterologists about diet?
- Peter:
- When we first presented this to people at meetings, they thought it was very amusing, funny little name you have there and this will go like everything else. And even the most vocal skeptics had changed their mind when they actually experienced it and saw. But what I think has influenced more has been the substantial body of data which is supporting the diet. The problem with dietary studies is that you can always criticize a dietary study that the placebo is not good enough, the blinding is not good enough, etc. etc. But what we have found is that studies all around the world now have, where there has been an attempt to blind, to do randomized studies have been positive, uniformly positive and that even in real-world practice which is what is really important that the diet has worked and has worked as predicted by the randomized controlled trials.
- Tracey:
- Right. It’s also difficult when you are doing dietary studies because a lot of the patient reporting is very subjective so often people want to hang their hat on something objective like a test. Is there a test that we can show that this patient really is experiencing less gas and bloating and feels better?
- Peter:
- We can do breath/hydrogen testing in clinical studies to show that they have got less gas being produced, hydrogen being the product of fermentation in the bowel. And if you reduce the diet you will reduce the gas. But in fact that is not a clinically useful test. In the early days when fructose malabsorption was considered one of the key elements of this, breath tests became very popular in Australia. And in fact what we found is that the fructose is slowly absorbed in all of us and distends the small bowel whether you malabsorb any or not. In other words a little bit might spill over into the large bowel but that is not relevant to whether a fructose causes problems. So in the early days people were doing a lot of breath tests to determine whether they should go on the diet, what sort of diet they should go on. You can do breath tests for fructose, for sorbitol, for mannitol, for lactose, all these sorts of things. But in fact now we find that the symptoms are due to irritable bowel syndrome, not due to this so-called malabsorption because the malabsorption is quite normal. Anyone you do it on, you’d have 40% of people will malabsorb 10 g of sorbitol for instance. But that’s got nothing to do with whether they have symptoms or not.
- Tracey:
- So we heard a lot about fructose malabsorption in the past but from what I am understanding from you, it’s something that is fairly normal in all of us and what we are really focused on is the distention in IBS. Can you elaborate on that for us please?
- Peter:
- Fructose malabsorption was very popular, a popular diagnosis in the past and then that meant that you needed a specific diet to reduce free fructose in the diet. But in fact most of the diets that were used for fructose malabsorption also reduced fructo-oligosaccharides which really has got no relevance to fructose malabsorption, which you malabsorb fructo-oligosaccharides all the time. So the breath test, all that, giving their diagnosis was really not terribly useful because I could take anyone off the street and they will have a 40% chance of having fructose malabsorption, because it’s normal. The other thing is that if you do a breath test for fructose today and repeat it in six weeks time it’s likely it’s about a half a chance it will be negative in six weeks where it was positive before. It is something which is not particularly useful. The other thing is that people who respond to a low FODMAP diet, the breath tests do not predict who is going to respond and there has been some very large studies in Switzerland that have indicated that. So what has happened is there has been an evolution where breath tests were often done, people were given these pseudo-diagnoses, which were really not the problem, the problem was irritable bowel syndrome and now what we are seeing is a marked reduction in doing breath tests and just getting in there and making the diagnosis of irritable bowel syndrome or bloating and then instituting the diet to see if whether they can respond or not. Now the, the other aspect is distention, you know bloating, distention of the abdomen is a major symptom, a worrying symptom to many people. They can put up with a little bit of discomfort, they can put up with altered bowel habit, it’s the bloating that really annoys people and this is due to the stretching of the bowel wall by gas and liquid. It doesn’t mean that it’s not because it’s like a balloon going up with a large amount of gas, but the actual distention itself is related to reflexes from the bowel to the diaphragms into the muscle wall which sometimes go the opposite direction in that when you distend your bowel, usually what happens is that the diaphragm relaxes and the anterior abdominal wall muscles tighten so that the volume in your abdomen is not increased. Whereas in some people with irritable bowel syndrome who distend a lot, this goes the other way and what happens is when you distend your bowel the diaphragm contracts and flattens the anterior abdominal wall become laxer and then the abdomen protrudes quite considerably. So this is a very interesting physiology. What we need to know is how to actually correct that and it will be things like biofeedback, physiotherapy, relaxation, things which may be the secret to that.
- Tracey:
- Right, yes. I think so.
- Peter:
- So that if you then reduce the distention by a low FODMAP diet, you can make an impact upon that but it may not be the hundred percent impact. So these other techniques are probably going to be of value. We are waiting for further evaluation of the sort of techniques.
- Tracey:
- Right. When you spoke about feedback is that talking to the brain?
- Peter:
- Well it’s really the biofeedback is really where it’s these unconscious reflexes, which we call visceral somatic reflexes that are, if you are doing true biofeedback you would see those muscles, you would have electrodes say on the diaphragm and it would show you they are contracting and then you can, by the power of the brain in the central nervous system, influencing that and looking at strategies to prevent that happening. We use it a lot in pelvic floor problems with the dyssynergia of the pelvic floor muscles. Where you can easily put electrodes in the muscles in the nerves in the rectum, fairly easy thing to do. And get the information. But in fact what we find now is that we don’t often need to do that because we can do the biofeedback in a way without it actually having the bio or the feedback, by just doing simple relaxation exercises. We hopefully will in the future be able to do the same for the distention of the abdomen.
- Tracey:
- For years patients with IBS were told that it was, their symptoms were due to stress. Can you explain to us why, doctors may have thought that end, what we know now is what is really happening?
- Peter:
- Well stress certainly influences the symptoms. If you are stressed you will, the outflow of the sympathetic nervous system will certainly increase the sensitivity for your bowel and change its physiology at least temporarily. And we know that when people get abdominal pain before exams they get diarrhea, before a very large, very big football match or something like that, and this is all part of the brain/gut axis which is very, very active. So stress certainly is factor which can make it worse, it’s not the cause however, there is a very new, although not so new, but a new push to look at psychological therapies more in irritable bowel syndrome.. Not only to improve stress coping but also to use the brain to change the physiology of the gut. And we know that things like cognitive behavior therapy can be very effective in irritable bowel syndrome and our favorite is gut directed hypnotherapy which we have now got a controlled trial which we randomize people to either getting gut directed hypnotherapy or low FODMAP diet, and they both worked about the same amount. About 70% of people were better in six weeks and it remained about that percentage at six months. So that what gut directed hypnotherapy does it also works on changing, we presume changing sensitivity of the gut and its physiology. And that’s using the brain/gut axis to influence what is going on in the abdomen. You get beneficial effects on anxiety but that is not the primary way these things work. So this has brought another arm to our therapeutic arsenal if you like for irritable bowel syndrome, that our psychologist hypnotherapists are getting much more involved. The biggest problem is finding people who have got the skills to do the gut directed techniques.
- Tracey:
- But the treatment sounds like it’s becoming much more holistic right? Instead of being all psychologically treated with cognitive behavioural therapy, now, we are considering that diet is playing a huge role here but also the stress effects on the microbiome and the changes that it causes to it. And the feedback that that gives back up to the brain.
- Peter:
- I agree and the treatment of irritable bowel syndrome used to be the gastroenterologist roll to use drugs and things which were, can help individual symptoms but weren’t particularly, didn’t have enormous impact and also not very good principle using drugs for a chronic condition when it should only work when when you take them. So that what happens now is that the irritable bowel syndrome and other functional gut disorders are now, the ownership of the management is with the GP, the gastroenterologist, the psychologist, the dietitian, the nurse, and more importantly the patient. The patient can be given a lot of strategies that they can change lifestyle issues like a diet, help with some simple psychological techniques to improve their lot. So I think the whole management regiment is changed. Obviously for the better in the last 10, 15 years.
- Tracey:
- I couldn’t agree more. Thank you Peter.
