#016 Dietitian Chloe McLeod Discusses Fructose Malabsorption And Other Intolerances

In this episode, Accredited Practising Dietitian, Chloe McLeod talks about fructose and sorbitol malabsorption, as well as other food intolerance and explains the difference between food intolerance, malabsorption and allergy.

Chloe Mcleod is an expert on both the low FODMAP diet and the food chemical elimination diet. Chloe helps others manage their food intolerance and symptoms also through the FODMAP Challenge program that she has created.

In this episode, you’ll learn:

  • What is the difference between food intolerance, malabsorption and allergy?
  • How true is it that fructose and sorbitol intolerance coexist in the same individual?
  • What will happen if the fructose and sorbitol intolerance person consumes food with it?
  • What is the difference between fructose malabsorption and hereditary fructose intolerance?
  • How accumulated low FODMAP foods trigger IBS symptoms.
  • Why portion sizes are important to the success of the low FODMAP diet.
  • How to determine if other factors should be considered if the low FODMAP diet isn’t relieving symptoms.
  • What is the other diet aside from the low FODMAP diet?
  • What is this FODMAP Challenge all about?
  • How can people join the challenge?


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Can’t listen to this episode right now? Read the transcript below!

LARAH: Hi, and welcome to the Low FODMAP Diet and IBS Podcast. My guest, Chloe McLeod, is an accredited practising dietitian. Chloe has had an interest in nutrition from a young age due to having food intolerances herself. Her key areas of speciality are in IBS and food intolerance along with sports nutrition and nutrition for arthritis and inflammatory joint disease. She’s passionate about motivating her clients to make positive health changes, and one of the favourite aspects of her work is being able to work with people with IBS, with Irritable Bowel Syndrome, and helping them live easier lives. As we know, one of the best ways of managing IBS is by following a low FODMAP diet, and Chloe has also created an online program called The FODMAP Challenge to help individuals determine the triggers of their IBS. She also works in private practice at Balmain Sports Medicine and Redfern Physiotherapy and Sports Medicine in Sydney and is the author of a cookbook as well. So here you go…my guest, Chloe.

LARAH: Hi, Chloe.

CHLOE: Hi, Larah. How are you?

LARAH:  I’m very good. I’m very excited to have you here today.

CHLOE: Wow, thank you so much for having me. I’m very excited to be here as well.

LARAH: Thank you. Well let’s start with the first question. So would you be able to tell the listeners a little bit more about yourself? How did you decide to become a dietitian and also if your personal food intolerances were a reason for you to get into this field? And you can talk about, of course, your interest in the low FODMAP diet and how did that come about?

CHLOE:  So I guess growing up with food intolerances, I’m quite aware of what I was eating and in what quantities which for me, luckily enough, actually really resulted in a love of food and how it affects your body.  Plus, I really enjoy talking to people and working with people and helping people. So becoming a dietitian really ticked a lot of the right boxes for me. My food intolerances are more around food chemical intolerances. The main part FODMAPs for me is onion and otherwise it is a slightly different to FODMAPs, but this has, I think, given me a really good understanding and empathy for management of food intolerances and what it’s like and when you maybe need to cut back on some of your favourite foods and not include your favourite foods, even if it is just for a while. And when I was in my first year working as a dietitian, the health service I was working for asked if I would be interested in going to the FODMAP education course which at that stage was being run out of Box Hill, and I guess, this is really where I first learned quite a bit about FODMAPs and then, as a result of that, I started seeing more people who required the low FODMAP diet. But I guess since then, I’ve been working a lot with people with IBS and other types of food intolerances and I’d seen that there weren’t any other programs around like the FODMAP challenge and that’s why I decided to go forward with that…and we’re getting some really great results so far.

LARAH: Yeah, perfect Chloe. Thank you for that. So in this podcast we often talk about food intolerances, food malabsorption and even food allergies. And what can happen for those of us who are not health professionals, we may use these terms interchangeably, but they don’t really mean the same thing. Could you please explain to everyone listening, what is the difference between an intolerance, a malabsorption and an allergy?

CHLOE: Of course. So with an intolerance, this is where it’s a dose dependent response. So an individual will be able to tolerate some of that food, but there will be a certain quantity where if more of that food is consumed, symptoms can start to occur. Now symptoms can be the gut-related ones which we are specifically looking at with IBS, but it can also be other symptoms as well, so some people get headaches and skin rashes and sort of foggy head and that sort of thing as well.  So intolerance can present in a number of different ways. With an allergy, it’s different in that you can’t tolerate any, so if any is consumed then an allergic reaction occurs. And this can either be an anaphylactic reaction or just in other ways…no more allergic reaction. With a malabsorption, this is where compounds of nutrients in the food aren’t digested properly in that they’re not transported through the intestinal wall well and this is often seen as a selective process. So, for example, in lactose malabsorption or fructose malabsorption, there’ll be some quantity of it which is absorbed through the intestinal wall, but not all of it. The parts that aren’t digested through the wall will end up in the colon, and that’s where they then ferment into short chain fatty acids that can cause the gut symptoms, which I think we all know quite well.

LARAH: That’s perfect, Chloe. That made it so much clearer. And is it then, that in terms of seriousness, let’s say malabsorption will be at the bottom, then the intolerance and then the allergy being the most serious one? Can we say it like that or…?

CHLOE: So I would say that an intolerance and a malabsorption, you could say, are probably are at a similar level of something to be concerned about because the malabsorption is looking at more of the process, whereas the intolerances, I guess, is more the overarching term of that. whereas the allergy is definitely, particularly in an anaphylactic allergy, and definitely the most serious because this can result in death in severe cases or in untreated cases. It is definitely something we need to be quite aware of and concerned about as well.

LARAH: Yeah, thank you, Chloe. It’s a very good explanation. In next week’s podcast I’m going to interview this lady called Jackie, and she suffers from a hundred percent fructose and sorbitol intolerance and apparently her case is very unique. Do you know by any chance, how rare is this condition and is it true that often fructose and sorbitol intolerance co-exist in the same individual? And also, if you could please explain one more question, what happens in the body and the digestive system of someone like Jackie if she consumes anything at all that contains fructose and/or sorbitol?

CHLOE: Yeah, of course. So I really feel for Jackie to get started, and it sounds like a really challenging situation to be in. It’s great to hear that she’s being diagnosed and learning how to manage her intolerances. I guess from that ‘how rare is it perspective?’ I don’t actually have a number of how many people who are one hundred percent intolerant, and she used that sort of terminology, but I do know that for quite a lot of people with IBS, fructose and sorbitol intolerance are a big problem.  Often they actually do coexist, as you mentioned, and then what the research actually shows is that when they are consumed together, an additive effect can occur. So if you eat an apple or a pear for example, where there is both fructose and sorbitol present, because that additive effect can occur, you might actually react more severely than say with a mango which has only got the fructose, or an apricot which has only got the sorbitol. So I guess with fructose and sorbitol, both of them are malabsorbed. So as I was mentioning before, they’re not taken in properly through the walls of the intestine and then when they end up in the colon, the fermentation occurs. So this is exactly what’s happening in Jackie’s digestive system. And if you can imagine, our intestines are a little bit like a hose that has hundreds of thousands of little holes all the way through it, and that’s how things pass through. That’s a very, very, very simplified way of talking about absorption mind you, but if we think about the sorbitol and fructose that for some reason don’t go through those little holes that are there — and again, simplified explanation — but none of that is going through for Jackie, whereas for some people, small amounts will go through, we can imagine that the severity of her symptoms is going to be much worse than someone who is able to absorb even sort of forty or fifty percent of the fructose and sorbitol that’s consumed.

LARAH: Okay, yeah, that made perfect sense to me. I guess the issue that Jackie has is that because her condition is quite unique, she really struggles with not knowing exactly the amount of fructose and sorbitol in food. For me, suffering from IBS and tolerating low FODMAP food is quite easy. I know I can have most low FODMAP food and not have any symptoms, but for her, a lot of the low FODMAP food has also got some sorbitol or some fructose. She even tried having a little bit more glucose to see if that would help, and it didn’t. So, yeah…

CHLOE: Oh, the poor thing. I was wondering if that was something that she had maybe tried or was considering trying. And you’re exactly right, Larah, in that even though, for example blueberries and raspberries are low FODMAP, they do still contain fructose. It’s just that’s it’s not there in excess like it is in other high fructose or higher fructose fruits, say that the watermelon or the apple or pear that that we were talking about before. She will definitely need to be much more careful in her intake and I can imagine that would make eating out and eating at friends’ houses to be a challenge, let alone just eating on a day-to-day basis.

LARAH: Yeah, it is a very big challenge for her because if she cooks at home she is fine. She knows what’s safe for her. And if she’s invited out or if she goes traveling then the problem arises that she cannot be sure of what the content is. That’s what makes the struggle bigger than any other IBS sufferers.

CHLOE: Yeah, definitely. I think with any intolerance, over time as you get to know your body better and what you can and can’t tolerate better, it does become easier to work out what’s on the ‘yes’, the ‘no’, and the ‘sometimes’ list and how they can be interchangeable as well.

LARAH: Yes. Yeah, I agree. So still talking about issues with fructose, would you be able to explain the difference between fructose malabsorption and hereditary fructose intolerance?

CHLOE: Yeah, of course. So I think we’ve already sort of spoken a bit about what fructose malabsorption actually is, and the real key difference between that and hereditary fructose intolerance is that with hereditary fructose intolerance, it’s actually an error in how the fructose is metabolised by the body. This is caused due to a deficiency in an enzyme called aldolase B. So for people who are actually similar to what we’ve been speaking about with Jackie, people who have this condition, if they ingest any fructose they’ll experience similar symptoms to fructose malabsorption such as nausea, bloating, abdominal pain, diarrhoea, vomiting and so on. Sometimes that’s where I think it can be difficult to diagnose. That said, it’s often determined in babies as well, and so often in infants, failure to grow and gain weight can also occur, or much slower than at the expected rate. So this is called failure to thrive and this can be a sign of it along with the other symptoms that I mentioned before.


CHLOE: Yeah, I guess one of the other things to think about with the hereditary fructose intolerance is that the tolerance isn’t going to change over time like it does with the fructose malabsorption for some people that may be able to tolerate more or less at different stages throughout their lives. With the hereditary type, ignoring it can actually result in long-term damage to the organs. So things like liver damage and kidney damage are some other really important things to be thinking about from a long-term health perspective. Really avoiding all fructose is recommended for those people.

LARAH: Yeah, thank you. And that sounds like quite a substantial issue that people might have.

CHLOE: Yeah, it’s not something which happens to a big part of the population. So I was having a look at some statistics with this, and what I could find was showing somewhere between one in around 17,000 and one in around 95,000 people who have the hereditary version of fructose intolerance. So I guess if you compare that to fructose malabsorption in like the Western world where that’s thought to affect up to around even 35% to 40% of individuals, it’s quite a big difference in the prevalence.

LARAH: Well that is quite an incredible number; 35% to 40%. That’s even higher than people that we say probably have IBS. You know IBS is about 15% we say.

CHLOE: Yeah, when I was reading that the other day I thought that it was really high. And I guess that sort of make sense as to why some people who don’t actually have IBS and sometimes get some symptoms but then they’re not too fussed by them. It’s just that they’re not absorbing the fructose as well as other people do.

LARAH: Yes, yeah, make sense. The next question is something I’ve seen asked a lot in different forums regarding the low FODMAP diet and regarding IBS. It’s about having too many low FODMAP foods. The question is, are low FODMAP foods cumulative? What I mean is that if I eat too many low FODMAP foods can this food take me over my individual threshold and cause IBS symptoms even though, like if I would have them individually, I am fine with them if I had them one per meal? So, for example, if I have a half a cup of broccoli, which is about forty-seven grams, and that would be low FODMAP. If I have one cup of broccoli, so double, ninety-four grams, then we know that that becomes high in fructans and GOS. So if I eat half a cup of broccoli, which is low FODMAP, and in the same meal I also have half a cup or sixty-six grams of zucchini — courgettes in other countries, it’s called. In larger quantities we know that for a hundred grams or three quarters of a cup of zucchini, it becomes high in fructans. And then I also have some other low FODMAP fruit, for example, a small bowl of raspberries and blueberries and we still keep the consumption of those berries at the low FODMAP levels, so we will have a twenty blueberries and ten raspberries.  So we know that for both larger quantities of the blueberries and raspberries will be high in fructans. So, can the accumulation of these foods bring me over the threshold?

CHLOE: It’s such a great question, Larah, and it really will depend. With the amounts that you’ve spoken about, it really will depend on the individual and just how sensitive they are. But I guess to get back to the question about it being cumulative or not is yes, they are cumulative in that everybody’s dose quantity that they’re able to tolerate is a bit different.  But when we add the different quantities of the fructans, to use this example together, this can then end up meaning that you can go over your individual dose that you are able to tolerate.  So even if most of the examples you’ve given now are the low FODMAP options, over consumption can end up causing a problem.  So, I guess I do like my analogies by the way. So I guess if we can imagine a set of stairs, and so the top of the set of those stairs is where your tolerance level sits. On each stair, there’s a portion of food that contains the FODMAP that you’re sensitive to, even if it’s not in a quantity that would normally be an issue.  And once we take each step up to the top of the stairs, which is your individual set of stairs, that’s when your symptoms are going to start. But if you had those things individually, or maybe even one or two things less, you wouldn’t notice a problem. Now I guess where it can become complicated is that with these low FODMAP things in the usual quantities that most people would eat, we don’t really find a problem with this cumulative effect. It’s more if it is the higher things, or even using the Monash app, using the moderate things. They’re the things with the orange traffic light. That’s when I find it’s more likely that people are going to find a problem and start to develop symptoms.

LARAH: Thank you so much, Chloe. That was such a great answer because a lot of people are concerned that the low FODMAP diet is not working for them, but maybe it’s because, as you said, their individual threshold does not allow them to have that many low FODMAP foods in one sitting.  So it’s really about trial and error a little bit, even if it’s low FODMAP.

CHLOE: It is to some degree. I think you know if, for example, it was the half a cup of zucchini, which we would expect would be okay, and the half cup of broccoli, and then say there was five raspberries and ten blueberries, I would expect for most people, from a FODMAP perspective, they would be able to tolerate that meal. It’s just when we get into those higher quantities, and that’s where I think that the traffic lights in that app can be really useful, that we can start to find things can get more complicated and more difficult.

LARAH:  Yeah, that’s right. And then if we calculate, like seriously, half a cup of zucchini is not that much.

CHLOE: Not that much, exactly.

LARAH: Yes, so, it is very easy that people might think that couldn’t be half a cup or three quarters, so you’re already going into the high level.

CHLOE: Exactly, so it is definitely important to be careful of the portion sizes.

LARAH: Yeah, absolutely. Yeah, thank you for that.

CHLOE: That’s okay.

LARAH: Some IBS sufferers only find partial relief from the low FODMAP diet. They say they feel a little bit better, but all their symptoms have not completely disappeared, even by following the low FODMAP diet. Is there anything else apart from having low FODMAP food that they should consider?

CHLOE: Definitely. So I guess to start off with, I’ll just highlight the importance of trialling the low FODMAP elimination and then working through the food challenges to determine which FODMAPs are likely to be the triggers. If at the end of the elimination phase though we’re not getting enough improvement, or as much improvement as we would expect, there are a couple of other things that I think are important to take into account. The number one thing there is stress. Stress has been shown to exacerbate symptoms in a number of different research studies. And also, IBS tends to occur quite regularly, not always, but quite regularly in people who tend to be a bit more stressed and a bit more anxious as well. So taking steps to manage levels of stress and any other things that are going on in your life is important and that’s actually something that I talk to people about quite a lot when they are starting the elimination of FODMAPs as well. Getting a good night’s sleep and including regular physical activity are also important things to take into account. I guess the other side of things that needs to be thought about though as well, is sometimes it isn’t just FODMAPs. FODMAPs isn’t the whole picture, so there are other foods which are not considered low FODMAP which can trigger IBS. Common ones are things like chili, fatty foods, creamy foods, coffee or caffeine and alcohol and all of those things are not considered to be technically, or usually not considered to be a high FODMAP food. Another thing to take into account if none of those things are getting enough of the improvement that we’re after, or if maybe there’s some other symptoms that are happening as well, then that’s where the food chemical intolerance can come in too.  So, you know, maybe it’s not just gut symptoms that an individual’s experience. Maybe there is that foggy head; maybe there’s irritability for no real apparent reason. Maybe there’s headaches as well, or asthma or hay fever. So these things are all signs that maybe it’s not just FODMAPs. Maybe it could be the food chemical intolerance side of things, And the reason why it can sometimes be really difficult to determine, is some of the low FODMAP foods are quite high in the natural food chemicals and vice versa; some of the low chemical foods are quite high in FODMAPs. That said though, quite a lot of the high FODMAP foods are also high chemical and so what is being shown in research which is coming out of the RPAH Hospital in Sydney is that, again with my analogies, think of it like when you are sort of at your tolerance line, like there’s a balloon and it’s blown up nearly the entire way and then if you go on the low FODMAP diet that balloon gets let down, let’s say about half way. So you come quite a bit under that dose line that you were able to tolerate and you’re feeling pretty great.  But then because you’re having these low FODMAP foods which aren’t necessarily always low in chemicals but you’re not really sticking completely low FODMAP, but that’s still going to result in that build-up based on the natural food chemicals. Again, and that’s why sometimes you might find that you feel better for a little while, but then that build-up can recur and that’s when the symptoms can start to come back. I guess that’s an area that I’m working quite a lot, partly from my own personal experiences but also because if there are other symptoms that are there as well, from my perspective and from what the research is showing that gives you really good insight, maybe it’s not all about FODMAPs. Maybe that’s only a part of the picture and they can often occur in conjunction with each other.

LARAH: Perfect. Thank you, Chloe, and that absolutely makes sense.  So, for instance…

CHLOE: Sorry for the long answer.

LARAH: No, no, that was so good. And so let’s say you see a patient that seems to have IBS or who has been diagnosed with IBS, so you go to the low FODMAP route and then this person improves, but not as much. So would you also so a food chemical elimination diet as well?

CHLOE:  I try not to do them in conjunction with each other or concurrently.


CHLOE:  …just because it’s really hard.  If we had a look at like a list of low chemicals foods and then a list of low FODMAP foods, there is definitely crossover. There’s not a lot in there and it ends up being incredibly, incredibly restrictive. There’s a couple of different ways that I tackle that and it really depends on the individual and where they’re at and what symptoms are the most difficult for them to tackle. So in some instances it might be that, well let’s take current symptoms as a baseline and then we go through the FODMAP challenges. And then once we’ve done that and we can realise some things, then we might go back and do some parts, or all of the food chemical side of things.  If we’re really not getting the improvements that we’d expect from my FODMAPs and there’s lots of other symptoms happening, then that’s when I’ll be saying, well why not give the low chemical diet a try.

LARAH: Yeah, great. I think for you, having the knowledge of both the low FODMAP diet… And is it called “Failsafe” the other diet?

CHLOE: I said that’s what Sue Dengate has called it, so she’s, I’m not quite sure, I think she’s worked in collaboration with RPAH to some degree to talk about that, but the allergy at the RPA hospital calls it the Food Chemical Elimination Diet. So that…

LARAH: Okay.

CHLOE: So that tends to be what I call it. But Failsafe, the terms can be used pretty interchangeably.

LARAH: Yes, yeah. So, that is so perfect that you have both the knowledge of the low FODMAP diet and the Food Chemical Elimination Diet as well. That is so good because you can see it from both sides.

CHLOE: Yeah, and I think you know every cloud has a silver lining. You never want anyone to have the intolerances or any health problems really bad, and when we can help so many different things through making food changes, it makes it really rewarding from my perspective.

LARAH: Yeah, I agree. Yeah, knowing that you can change lives, that’s great.

CHLOE: Totally, totally.

LARAH: So, I’m very conscious about the time running out, so let’s go to our last question, which is… well, it’s the second last. So you also have created a low FODMAP diet challenge.  Could you tell the listeners what it is and how people can join the challenge?

CHLOE: Of course. So with the FODMAP challenge, it’s an online program where myself and another dietitian will take you through the elimination phase of the low FODMAP diet and then through each phase of the food challenges of the process I suppose. So throughout the twelve weeks, we provide meal plans, recipe ideas; there’s a private online Facebook group, where people can ask questions and I do a weekly live chat, if people want to talk about anything in particular. We have weekly videos as well, to explain things that are sort of daring in each weekly session of the website. And for the first four weeks of the elimination, we have a bit focus on other things which are not necessarily food related to help with managing your symptoms, so for example, the stress management that I was talking about before. We also have included a last week as well, a bonus week or the thirteenth week program if you like, and that’s where we start talking about reintroductions and how to work out what your individual tolerance levels are. And once the program is finished, people keep having access to all of the recipes and keep having access to the group as well so that if they’ve got questions after the program is over, then they can still ask questions.

LARAH: That’s really, really good. And this is obviously not just for people in Australia, but from anywhere in the world. They can all access your low FODMAP challenge.

CHLOE: Yeah, exactly right. So I guess part of the reason of where the idea came from is that I actually grew up in the country and I was quite lucky in that we had quite a good health service there. But I also know that there isn’t always necessarily someone who is in the country town that you’re in, or even in the country that you’re in when it comes to food intolerances, who really knows what they’re talking about. So I guess part of the beauty of the online process is that you can be anywhere, and as long as you’ve got an internet connection and be able to have access to really good information and have that ability to ask questions any time that you like.

LARAH: Great. And so do you that at different times of the year or can people join at any time?

CHLOE: Well at the moment, we’ve been doing it on a start-date basis, so the September challenge just started last week. We planned it so that that one will be finishing up at the start of December just in time for people to know what their symptoms are, or to know what they’re triggers are, before Christmas.  We’re talking about doing a sign-up anytime come January, so watch this space I guess.

LARAH: Great, thank you. And all the information can be found, obviously, on your website?

CHLOE: Yeah.

LARAH:  So could you just list all that you think will be useful for people to get in touch with you, so your website and your social media…anything?

CHLOE: Of course. So the FODMAP Challenge website is fodmapchallenge.com. My personal website is chloemcleod.com. Regarding social media, I use Instagram more than I use anything else, so that is @Chloe_McLeod_Dietitian. The FODMAP challenge has its own Facebook page as well. There’s a public group as well as the private group. So the public page is, if you just Google the FODMAP challenge or search for the FODMAP challenge within Facebook, it should come right up.

LARAH:  Great, okay. So all the links and all the websites that you mentioned will be posted on the show notes for this episode, as usual, so it will be just as easy to go in there and just click and be able to get in touch with Chloe.

CHLOE: Perfect. Thank you so much for having me, Larah.  I really appreciate it.

LARAH:  Thank you so much for being here.  You’ve answered some really important questions and I hope that in this episode the listeners have found more information that will help them and guide them even if it’s to ask the right question to the health professional.

CHLOE: Exactly right.

LARAH: Alright, we’ll talk to you soon. Thank you, Chloe.

CHLOE: Alright, Larah. Enjoy the rest of your day.

LARAH: And the same. Thank you, bye.

LARAH: I hope that you have enjoyed this episode with accredited practicing dietitian Chloe McLeod and that you were able to understand things like the difference between food intolerance, food malabsorption and allergy as well as fructose malabsorption and hereditary fructose intolerance and also what can happen if we consume too many low FODMAP foods during the same meal and all the other useful information that were discussed today. If you would like me to cover a specific subject within the topics of IBS and the low FODMAP diet of course, please visit my website or Facebook and send me a message and I’ll certainly do my best to recruit the right specialist who would be able to answer your question. If you are enjoying the content of this podcast, it would be absolutely amazing if you could go on iTunes and submit a review for the podcast and help me to increase the subscribers and therefore spread the word about IBS and the diet even more. As always, you will be able to find the show notes for this episode with all the links discussed on my website.  Well, this is all for now. I wish you great health and happiness and I’ll talk to you next week. Goodbye.

Links to Chloe’s websites:

Links to Chloe’s social media:

About Larah

I have been suffering from Irritable Bowel Syndrome for many years, but it took a longtime to get a diagnosis, since then I have been following a low FODMAP diet, which has changed my life for the better. This is my story and experience with IBS and the low FODMAP diet.