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How & When to Use the FODMAP Diet

Dr. Peter Gibson, MD

dr-peter-gibson-md

Dr. Peter Gibson, MD

The Alfred and Monash University

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Overview

The FODMAP Diet has been used since 2004 to reduce symptoms of Irritable Bowel Syndrome (IBS) and other functional bowel disorders. Dr. Peter Gibson is a Professor and Director of Gastroenterology at The Alfred Hospital and Monash University in Australia – and the creator of the FODMAP Diet. The FODMAP Diet limits short-chain carbohydrates that can ferment in the colon and lead to symptoms in people with functional bowel disorders. In this interview, Dr. Gibson will provide guidelines on how and when to use the FODMAP Diet to reduce symptoms of bloating, abdominal discomfort and pain.

Transcript

  • TRACEY:
  • We are here with Dr. Peter Gibson from Monash University in Melbourne Australia, he also works at the Alfred hospital. Dr. Gibson and his group developed the FODMAP diet and I want to thank you for joining us here today because so many people are hearing about the FODMAP diet and are interested in it and want to know, you know, what it can help with.
  • PETER:
  • Well the FODMAP diet was developed for people with functional gut symptoms particularly irritable bowel syndrome. It’s a diet in which the principles are that any of the short chain carbohydrates like sugars, oligosaccharides, disaccharides, that are slowly absorbed in the small intestine or cannot be digested so aren’t absorbed, are reduced in the diet. So the basis of the diet is to choose foods which have a low content of FODMAPs and to instead avoid the foods that have a high content. And the term FODMAP was basically created because there is no term to cover all of these particular carbohydrates.
  • TRACEY:
  • Right.
  • PETER:
  • And they include, they include fructose when it’s in excess of glucose. Lactose if the person is, can’t digest lactose. Polyols like sorbitol and mannitol. And then the very important group, the oligosaccharides which are in food and mainly the fructo-oligosaccharides and galacto-oligosaccharides.
  • TRACEY:
  • Right, and you know when you start looking at all of these different foods I think it’s very challenging for someone to figure out what all of these, how all of these foods are all related together. How did your group come to figure out what foods were part of the FODMAP and how did you start grouping them together to make it easy for patients to follow?
  • PETER:
  • Well we knew that individually all of these things cause symptoms and so that’s why we put them together because they all do very similar things, because they are poly absorbed or not absorbed they bring more water into the small bowels so distend the small bowel and they also are very readily fermented by bacteria in the large bowel, when they reach the large bowel. So one of the things is the effects of producing a lot of gas as well as water is that it distend the bowel. So it stretches the bowel wall and this is a major stimulus for symptoms in people with irritable bowel syndrome because this is part, this is what we call visceral hypersensitivity. So about 70% of people with irritable bowel syndrome for instance will have visceral hypersensitivity when you measure it using balloons in the rectum or in the stomach or somewhere like that, and the idea was that instead of just reducing one thing that will distend the bowel like that we should reduce all of the things that do that. And it seems to work.
  • TRACEY:
  • Right, right. So do all the functional bowel disorders respond to the FODMAP diet?
  • PETER:
  • Well to date the only clinical trials have been done in irritable bowel syndrome but there is also some evidence that it can help people with functional dyspepsia. There is an yet unpublished study from Hong Kong on that. But it does help people who have bloating and people, there is one group of function disorders which is called functional bloating and that is something that it is really very good for.
  • TRACEY:
  • So this diet, if it is helping with the function it wouldn’t necessarily help somebody who has, for example Crohn’s disease unless they had a type of Crohn’s disease that also had a functional bowel disorder on top of it. Then they might see some benefits from the diet. Is that correct?
  • PETER:
  • Yes, it is not an anti-inflammatory diet, it’s not a diet that cures irritable bowel syndrome or visceral hypersensitivity. It’s just a diet which reduces the likelihood of getting symptoms. So in Crohn’s disease, ulcerative colitis, functional disturbances are very common. And we also find that the diet is very useful in those settings. However if someone has a very inflammatory bowel disease it’s not the treatment for it because you need to get rid of the inflammation and this is not an anti-inflammatory diet.
  • TRACEY:
  • Right. Is there some connection between this diet and the microbiome that is living in the small intestine, large intestine?
  • PETER:
  • It certainly is because one of the major factors in the pathogenesis is the fermentation of the FODMAPs, the poly absorbed FODMAPs. It’s not the only part, but the microbiota are key to, to developing the increased gas production in the distention of the bowel. That doesn’t mean that people have to have abnormal microbiota for it to be effective. What it means is that the microbiota just by its normal, fermentation activities will produce the gas. So anyone who doesn’t have irritable bowel syndrome takes… Has a lot of FODMAPs, that will extend their bowel just like someone with irritable bowel syndrome because of the microbiota and because of the osmotic effect. But what the difference is that people with irritable bowel syndrome or other functional gut disorders will respond to that stretching of the bowel wall differently to healthy people. So it’s not that the microbiota have to be abnormal in irritable bowel syndrome for this diet to work.
  • TRACEY:
  • I understand.
  • PETER:
  • And the other thing with diet, there’s a lot of evidence now that gas reduction in people with irritable bowel syndrome is not more than people who don’t have irritable bowel syndrome. The difference is that it’s, is the sensitivity to the, to the gas. And expansion.
  • TRACEY:
  • Can the FODMAP diet be used for an acute, for example after you have had some sort of gastrointestinal illness and you have been left with a post-infectious gas and bloating. Would a FODMAP diet work in that situation?
  • PETER:
  • Well yes because it will help. Because it will reduce the gas and the bloating and so it can be used at any time, it can be used by, you know a lot of people get, or most of us get bloating and wind and problems from time to time. That if it is a problem you can reduce your FODMAPs and then it will help. However what we don’t want is people to be taking the low FODMAP diet as all the time just in case they get things. Because it is not a diet for good health it is a diet which is designed to help symptoms. And so you don’t want to be on a restrictive diet, where certain things are not available to you to eat. The risk is that you are going to, change your microbiota, you might reduce the nutritional adequacy of your diet. And even more importantly, it might make life miserable for you. Go to a restaurant, you don’t know what to eat, friends won’t invite you to dinner because they don’t know what to feed you. It’s a diet really for people who have symptoms who will benefit from that. It’s not something you should take just in case.
  • TRACEY:
  • Right. So somebody with IBS for example, how long should they go on this diet for in order to see results?
  • PETER:
  • Well if they go on it very conscientiously, and do it quite seriously, they should see results within the first week. When we feed people food which is low in FODMAPs, the response is within seven days. And it makes sense because that’s when the distention reduces very quickly because these things are induced distention, you know within the first 24 hours of eating. So it is a fast onset. We usually ask people to try it for four weeks or so before assessing whether it is worked or not because people do find, it gives a time of adaptation so that they can get seriously onto the diet and learn the things that they should avoid and things that they should replace them with.
  • TRACEY:
  • Right. So somebody with IBS, they do their 4 to 6 weeks, they definitely see improvement, how long should they continue?
  • PETER:
  • What we would recommend is that they then go on a reintroduction program, and this of course is not easy for someone doing it by themselves without the assistance of a trained person, health professional such as, particularly a dietitian or it could be a nurse. We have had nurses who are well-trained in the diet. And then the idea being that you would try individual foods with individual FODMAPs and it because some people are much more sensitive to some FODMAPs than others. And the idea is that with this reintroduction you find the level of FODMAP restriction that you need to maintain yourself in good health with few symptoms. So it is all, it’s reintroducing to tolerance. And what we find is that about 75% of people have only a small amount of restriction in the longer term. For instance they might just never go near onions again. They might, very seldom have more than a very small amount of wheat products which have got a lot of fructans and fructo-oligosaccharides in them. But they don’t have to be serious about all the other FODMAPs. So it sounds very complex but in fact with good instruction it’s quite remarkable how people can understand the diet and can function very, very well. Will know their foods and will be able to maintain themselves with a few symptoms. Of course, sometimes people will inadvertently have something with a lot of onion in it and they will know, they will know, they get symptoms. They are not unhappy because they understand why they got their symptoms. Whereas in the past if people got a bad bout of symptoms, they didn’t know why. What was it that I had, and they will blame the wrong food or something else for it.
  • TRACEY:
  • Right. In your research has there been any evidence to show that there are people that just won’t respond to this diet?
  • PETER:
  • It’s always about 30% of people who don’t respond. Some studies have had up to 50% who didn’t respond, though quite highly selected patients in those studies but it’s about 30%. Now we know it’s interesting that about 30% of people with irritable bowel syndrome do not seem to have visceral hypersensitivity. The idea is that perhaps that’s the group that doesn’t respond. The group that is always hardest to get to respond to any therapy for irritable bowel syndrome are people who got quite severe symptoms. So, it’s not the panacea, in the past we haven’t had any therapy that has been effective in three out of four patients.
  • TRACEY:
  • So just to clarify in the reintroduction stage, how long should a person wait before they introduce the next food? Let’s safe for example, they do a reintroduction of onions and then they want to do a reintroduction of garlic, how long should they wait?
  • PETER:
  • Probably two or three days but you should start with a very small amount and find out what level they will tolerate. This is not something that I would claim expertise on how to reintroduce but there are some very good guidelines in the Monash University FODMAP diet app as well as in some literature, recent article which gives some good guidance on this. I must say that the reintroduction phase has not been tested in randomized control trials but those are currently being done by groups. Not our group but other groups.
  • TRACEY:
  • Right, okay, that’s helpful. Your app is so straightforward and I love their red light, green light, yellow light. It makes it so easy for patients to follow. Can you tell us a little bit more about how the app was developed and how you see it being used?
  • PETER:
  • Well the key to the diet is to know what foods you can and can’t eat and how much of them would be safe to eat without getting symptoms. We have for the last 12 years have been measuring the FODMAP content of foods because there were very poor databases of this in the literature. Very patchy and some of it was very old and not, we didn’t think terribly accurate. So what the app enables us to do is to put all of the database on the app as we do it because the app can be updated daily if necessary. So that all of the most recent information is available to people in the community. This has been really important because what we were finding was that people would come to see us and said, this diet doesn’t work and we would say, how did you start and they would say, I was given this piece of paper, and it was a photocopy of a photocopy of a photocopy of something that was written 12 years ago at the beginning when we had incomplete information. So that it’s very important – there’s a recent study from the United States where they looked at links to the low FODMAP diet and found quite inaccurate information on most of them. Because they weren’t up-to-date or because they misinterpreted data. So this is the idea, that the app contains everything that is, that has been measured and not, no guesswork in there. The other thing about the app was that it was really the brainchild of Dr. Jane Muir who runs our translational research group. And it has been a really marvelous way of actually implementing a diet and helping people to actually follow it more readily. Because even though it’s not, it looks very complex, but it’s not really that hard once you put in, put in a bit of effort into it.
  • TRACEY:
  • Can you elaborate a little bit more about what symptoms people should be looking for and what symptoms, besides the bloating come with this and that can be helped by the FODMAP diet?
  • PETER:
  • Well the most common symptoms are bloating, abdominal discomfort and abdominal pain and change in bowel habits. Which can be diarrhea, constipation or an erratic bowel habit which is very common. So that the symptoms of course can be symptoms of other things, inflammatory bowel disease, celiac disease, it depends on what age the person is having them. So it is really important to, before going on any restrictive diet that people do see their doctor, exclude celiac disease – that’s very important because a gluten-free diet is a much better therapy for that. It’s an essential therapy for celiac disease. And then, get a diagnosis of irritable bowel syndrome or other functional gut disorder to be established before going on a restrictive diet. This is really important because it may not be suitable for the person or it may not be the right thing for them.
  • TRACEY:
  • Right, that is very important, those are very wise words. So often people just go and try and implement these things themselves without really knowing what they are trying to treat.
  • PETER:
  • That’s right and the other thing of concern to us is that they are, some people and even some doctors who are using response to the low FODMAP diet as a diagnostic test. If you respond to it, it must be irritable bowel syndrome. That is not the way to do it because if you have symptoms from celiac disease, you go on a low FODMAP diet, the symptoms often do improve. But that doesn’t, that’s not, you need to get the diagnosis made properly before you start restricting foods.
  • TRACEY:
  • Yeah, right, very important. Thank you, thank you for this wonderful information that you have shared with us on the FODMAP diet.
  • PETER:
  • Thanks.