The Gut Health Podcast

Is it IBS? IBS Mimickers

• Kate Scarlata and Megan Riehl • Episode 3

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Irritable bowel syndrome (IBS) impacts more than 45 million Americans and about 1 in 10 globally. So, if you have abdominal pain, diarrhea and/or constipation on a regular basis...you are not alone. We are thrilled to have world-renowned gastroenterologist, Dr. William Chey, on this episode to discuss this diagnosis along with common IBS mimickers.  Dr. Chey is the Chief of Gastroenterology at the University of Michigan and a true physician champion for the importance of a multidisciplinary approach to the management of IBS. He discusses how this complex condition, once perceived purely as a psychosomatic disorder, has evolved into a multifaceted syndrome with new and improved treatment methods. Discover the transformative potential of dietary strategies like the low FODMAP diet, the integration of behavioral therapy along with complementary and alternative medicine (like acupuncture) into patient care, as we explore the nuances of treating IBS and its masqueraders.

Dr. Chey sheds light on the enlightening findings from a recent study on disaccharidase deficiencies, particularly the surprising prevalence of sucrase-isomaltase deficiency in IBS patients with diarrhea predominance. Gain insight into the challenges of current testing methods and the role of bile acid malabsorption, which opens the door to a more precise and personalized approach to managing unruly gut symptoms. The conversation steers toward the promise and limitations of breath tests and the significance of a Dream Team approach, blending expertise from various specialists to address the unique needs of each patient.

 We also delve into the intricate relationship between small intestinal bacterial overgrowth (SIBO) and bile acid diarrhea, and the innovative work of researchers like Dr. Mark Pimentel. Dr. Chey emphasizes the growing importance of precision medicine in the field of gastroenterology and gut health, highlighting the complexities of diagnosing and treating conditions such as SIBO.

While we share a wealth of knowledge that promises to enlighten both healthcare professionals and individuals navigating the intricacies of IBS and it's common mimickers, you won't want to miss the introduction to a very special guest! Welcome Mabel June Scarlata (hint: she's the Scarlata family's new chocolate lab puppy).  Don't forget to subscribe and share – your gut will thank you!

P. S. Find Mind Your Gut:  The Science-Based, Whole-Body Guide to Living Well with IBS by Kate Scarlata MPH, RDN and Megan Riehl, PsyD which covers all things IBS along with IBS Mimickers in Chapter 10.

This episode was sponsored by QOL medical and Schar.

Learn more about Kate and Dr. Riehl:

Website: www.katescarlata.com and www.drriehl.com
Instagram: @katescarlata @drriehl and @theguthealthpodcast

Order Kate and Dr. Riehl's book, Mind Your Gut: The Science-Based, Whole-body Guide to Living Well with IBS.

The information included in this podcast is not a substitute for professional medical advice, examination, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider before starting any new treatment or making changes to existing treatment.

Kate:

This podcast has been sponsored by QOL Medical and Schar. Maintaining a healthy gut is key for overall physical and mental well-being. Whether you're a health-conscious advocate, an individual navigating the complexities of living with GI issues, or a healthcare provider, you are in the right place. The Gut Health Podcast will empower you with a fascinating scientific connection between your brain, food and the gut. Come join us. We welcome you. Hello friends, and welcome to The Gut Health Podcast, where we talk all things related to your gut and well-being. We are your hosts. I'm Kate Scarlata, a GI dietitian.

Dr. Riehl:

And I'm Dr Megan Riehl. We have a very exciting podcast for you. We are talking about irritable bowel syndrome and conditions that may co-occur with IBS, or perhaps are an IBS mimicker all on their own Our special guest today is Dr William Chey.

Kate:

He's a world-renowned gastroenterologist and the chief of gastroenterology at Michigan Medicine. He has authored more than 400 manuscripts, reviews, chapters and books, including more than 10 national and international clinical practice guidelines. He's a researcher, medical innovator and holds several patents. Finally, dr Che holds several leadership roles with national gastroenterology organizations and is a mentor and really a dear friend of mine and Megan's. He will delve into the diagnosis of IBS and when to consider if something else might be contributing to your GI woes.

Dr. Riehl:

So in the world of gut health, we like to bust myths and address misinformation, because there's a lot of stuff out there that is not based in science or coming from reputable sources, and when it comes to IBS, we have one of the most credible sources in the field of gastroenterology. We have one of the most credible sources in the field of gastroenterology, Dr Chey. What is a common misconception about gut health or GI disorders that you would like to dispel for our audience, as we kick off our episode today.

Dr. Chey:

First of all, thanks so much for having me on your podcast. You've both been guests on my podcast, Gut Talk, and we've had some great conversations, so it's interesting to have somebody describe this topic as stimulating. And so you know IBS. I think there remains a lot of confusion about IBS because when doctors give a diagnosis of IBS to a patient, they often do it in a situation which is really more default mode than feeling really confident that a patient has IBS. You know they do a whole bunch of different tests. We're going to talk about conditions that can masquerade as IBS, and that uncertainty on the part of the provider is picked up very, very quickly by the patient. You know, if the provider isn't sure about what's going on, why should the patient have confidence that they're going to get the right treatment? You know, and so therein lies one of the great conundrums related to IBS. It's coming out of the box with this diagnosis. It's one of the foundational issues that confronts providers and patients.

Dr. Riehl:

Yeah, it's complex and with so many people around the world struggling with the symptoms that we're going to ask you to talk about today. I talk about this with my patients that if you haven't received a definitive diagnosis, you're going to keep looking, and we want you to stop looking unnecessarily.

Dr. Chey:

Yeah, that makes total sense.

Kate:

So can we start with just the basic what is IBS?

Dr. Chey:

Yeah, and this is an important thing to tag on to the conversation we just had. So, by definition, IBS is a symptom-based condition that includes recurrent bouts of abdominal pain and altered bowel habits and, confusingly, patients that have diarrhea so loose or watery stool, constipation, hard or lumpy stool or a combination of both diarrhea and constipation can all get diagnosed with IBS. And it should tell you this. One fundamental truth about IBS is it's not one disease. It's probably a number of different diseases for which we don't at the current time, have a definitive diagnostic test to be able to put patients into true disease buckets, and for that reason we have this syndrome. You might notice it's irritable bowel syndrome, not irritable bowel disease, and the reason for that is because, as a syndrome, it's defined by the presence of symptoms and it probably includes a number of different diseases for which we can't separate at the current time.

Kate:

I wanted to talk to you, Dr Chey, about just how treatments for IBS have changed since you've been working in this field. I know there's been a lot of sort of new research and new thoughts about IBS. What's really changed in your career?

Dr. Chey:

I get asked this question a lot and I've thought about it and it's really an interesting evolution to think about what's happened over the last 30 years. First of all, it's unbelievable to think that it's been 30 years, but it has, and things are so different now. What I teach the fellows now is completely different than what I was taught in 1990 as a GI fellow. You know, in 1990, as a GI fellow, I was taught that IBS was largely a psychological condition, that treatments were really predicated on finding the right medication for the right symptoms, so an antispasmodic for abdominal pain, an antidiarrheal for diarrhea, a laxative for constipation. It was literally at that level of sophistication and there were very few treatment options, if any, at that time, that addressed multiple symptoms in patients with IBS. It really was like using multiple medications to pick off individual symptoms and the field moved towards medications that address multiple symptoms. So we started to see drugs like linaclotide, olocetron, tagasterone, like drugs that would not only address constipation or diarrhea but also abdominal pains, in some cases bloating. But it was still focused almost exclusively on medications, exclusively on medications.

Dr. Chey:

And then, probably in the first decade of this new century, we started to really see an explosion of literature, particularly around the importance of behavioral issues and the potential value of behavioral therapies for patients with IBS. And a little bit later than that but not too much later, but a little bit later than that we started to see more stuff on diet and nutrition and in particular around 2005, 2007, monash started to publish about the low FODMAP diet, which really, I'll tell you, for me was really an epiphany. It really changed the way that I thought about IBS. To this day, we still argue about whether food is the cause of IBS or a trigger for IBS. I personally favor the latter, but it really the whole idea of FODMAPs helped me to understand that patients have this condition, ibs that's hallmarked by visceral hypersensitivity and abnormalities and motility, and that you know, of course, if you have a trigger like FODMAPs, it makes sense that it's going to exaggerate the motor response and the sensory response in regards to developing symptoms.

Dr. Chey:

And now you think about, like in 2024, anybody that gives a lecture on IBS is going to talk about medications. They're going to talk about diet. Bs is going to talk about medications. They're going to talk about diet. They're going to talk about behavior. And I dare say I literally just gave a lecture on IBS a couple days ago and cam therapies as well complementary alternative medicine therapies. Megan knows us. We started. We've actually voted with our feet. We actually have an acupuncture clinic embedded in our GI clinic now at this point we're the first large academic medical center in the country to do that. But the feedback I've gotten from patients regarding the potential benefits or the benefits in their case of acupuncture for their IBS symptoms has been really stunning to me. I absolutely expected a positive response, but really thankful patients sending me just sort of cold, sending me emails telling me how much it's made a difference for them, and so I would say that that should also be part of our armamentarium.

Kate:

I think we've seen this in the data and you know, working with patients for 30 years now that have IBS they want holistic approaches. Most of them don't really necessarily want to do medication, so I could see them being very happy about having I mean, you have all of those services at Michigan Medicine, which is amazing. I just wanted to backtrack a little bit for our listeners that might not be familiar with FODMAPs. The low FODMAP diet is a diet that's done in three stages. Fodmaps are a group of carbohydrates that are commonly malabsorbed we won't get into them in detail today, but in another podcast for sure but these are commonly malabsorbed carbohydrates that can trigger symptoms associated with IBS. So I wanted to just kind of delve into this question. You know you've got someone, you think they have IBS. You try different therapeutics. Nothing seems to kind of work. Do you start thinking maybe it's something else? What are some of the signs and symptoms that you see in practice that you say, hey, there's something else going on?

Dr. Chey:

Yeah, this is a really important question, because there are two parts to this question. The first part is what is the patient, upon your first seeing them, that you should really think hard and long about providing a diagnosis of IBS. And then, what do you do about the patient that isn't responding? Do you worry more about that? You're missing something else, or should you be thinking differently about how to approach their treatment? So, taking on the first thing, who are the patients that deserve a more detailed evaluation when you first see them? That you think they might have IBS, but, but you're not sure. To me, patients that have more severe symptoms, patients that have symptoms beyond the breadth of the normal IBS patient, I think deserve a more thoughtful approach and more detailed workup coming out of the box. Also, patients that have so-called warning signs or alarm features. This is by no means a perfect science, but it does help to identify patients who deserve a more detailed initial workup, as opposed to the more symptom-based approach and limited workup that we do for most patients with IBS that don't have warning signs or alarm features.

Dr. Chey:

So what are those warning signs or alarm features? Well, first is evidence of gastrointestinal bleeding Patients that tell you that they're seeing blood with their stool, having black stool. You should take much more seriously. In addition to that, patients with unexplained iron deficiency anemia are another group that again you have to take seriously. That again you have to take seriously. The society guidelines, ACG, AGA all recommend a detailed structural evaluation for every patient with unexplained iron deficiency anemia. Significant unexplained weight loss is also an important warning sign or alarm feature, and most people talk about that. It'd be wonderful to give you an evidence-based threshold, but probably on the order of around 5 to 10 pounds of unexplained weight loss you should be interrogating more carefully. Another really important warning feature it's not really a sign or a symptom, but it's a family history of gastrointestinal malignancy.

Dr. Chey:

And here we are doing this podcast in March and it's Colorectal Cancer Awareness Month, and so I'm just going to give my plug that obviously everybody that's over the age of 45 should be undergoing some form of colorectal cancer screening. By the way, that doesn't mean that it has to be colonoscopy. You know, average risk patients can be tested with FIT or Cologuard and that's perfectly adequate. But those patients with warning signs should get a colonoscopy. But it's not just colon cancer that's important from a family history standpoint. Remember that patients with a first degree relative that has inflammatory bowel disease also has an increased risk of IBD, and then patients with a first degree relative with celiac disease also have an increased risk of celiac disease. So you should always ask about colorectal cancer, IBD and celiac disease as part of your screening process when you're seeing a patient that you are suspicious might have IBS.

Kate:

Can you just elaborate on FIT and Cologard for the listeners that might not know about those products?

Dr. Chey:

Sure or genetic markers genetic changes in stool samples that identify patients who are more likely to have either adenomatous polyps or cancer. It's another method and, as I mentioned a moment ago, it's really intended for average risk patients. Patients that have had a previous history of adenomas or a family history would not be appropriate for stool-based testing, but for those that don't have a family history and don't have a history a personal history of cancer or adenomatous polyps so-called average risk patients a stool-based test is perfectly adequate.

Kate:

Perfect, and so I'm having my colonoscopy next week, just so you know, good girl. Just to get back to the initial question beyond alarm features, is there something else that prompts you to start thinking mimickers, no family history, no alarm features. Is there some red flags that say, hmm, there's something else going on?

Dr. Chey:

I'm glad you came back to this because I forgot a really important alarm feature that I think there's confusion about, and this is a really important point you know people always talk about. You might notice that I did not say nocturnal pain, and yet if you read a lot of review articles and certainly some of the older literature, they all refer to pain that awakens you at night as an alarm feature or alarm symptom. It turns out that's not true. The studies that have looked at this there's multiple studies that have looked at this have found that the likelihood of having organic disease is no different between patients with IBS symptoms that don't have pain that awakens them at night versus those that do so. Pain that awakens them at night versus those that do so.

Dr. Chey:

Pain that awakens you at night is not an alarm symptom, but diarrhea that awakens you at night is a very potent alarm symptom, and that's also something that answers the question that you just raised. What is a red flag for me that really gets my ears up in clinic is when a patient tells me that I have to get up at night with diarrhea. That is almost never IBS. I mean occasionally it'll turn out that way, but almost never Almost always, a patient that tells you that they're having episodes of diarrhea at night will have some other organic disease, and so those are patients that I pay particularly close attention to in terms of making sure they don't have any of a variety of diarrheal illnesses, some of which we'll talk about today.

Kate:

What are some of the most common IBS mimickers that you see in your practice?

Dr. Chey:

It's funny because the things that we providers and patients know about the most they're important to know about, but they're not necessarily the most prevalent. So, for example, almost everybody knows about the overlap between celiac disease and IBS. In fact, we've published a lot of papers about that. You know, we published one of the original meta-analyses suggesting that we should be looking for celiac disease in patients with IBS symptoms. We're also, though fortunately or unfortunately, one of the first ones to publish prospective real-time clinical trials showing that the prevalence of celiac disease was not that different than the prevalence of celiac disease in the general population. And, by the way, what is that number? The number is probably 1% or less. So so you definitely will see it if you look for it. But think about it. That means that you're going to have to test 100 IBS patients and, by the way, it's IBS-D patients, for the come up to me and say you know, you wrote all these papers about how we should be testing for celiac disease in IBS patients. I test every one of my IBS patients and I never find celiac disease, and my response to them is you're right, you will have to test 100 patients to find one with celiac disease. Actually, the true number is probably more on the order of around 150. So it's not that you'll never find it, it's just that you won't find it that often.

Dr. Chey:

But why is it worth doing? Because celiac disease is a profoundly important diagnosis to make. It's not a diagnosis that you want to miss. Why? Because there are so many downstream consequences to not making the diagnosis of celiac disease. Being misdiagnosed as IBS when you have celiac disease could potentially have catastrophic consequences for the patient 5, 10, 15 years down the road, including an increased risk of cancer. So it's just not a diagnosis that we can afford to miss. So, even though it's not that common, it's important to look for Things that are more common are things like microscopic colitis.

Dr. Chey:

That's still missed a lot, although less often now than 10 years ago. But microscopic colitis probably is going to be present in somewhere between 3% and 5% of patients with IBSD symptoms that don't have warning signs, by the way. So for those patients that have nocturnal diarrhea, for those patients that are not responding as well as you might expect to some Imodium or other treatments for IBS-D, think about microscopic colitis. Make sure that if a patient gets a Flexsig or a colonoscopy that they get random biopsies to be sure that you've excluded microscopic colitis.

Dr. Chey:

Bile acid diarrhea is also really common. Put it this way, bile acid malabsorption is probably present in 20% to 25% of IBS-D patients. Now the degree to which that bile acid malabsorption is responsible for the patient's symptoms is still a bit unclear. But even if 50% of those patients, their symptoms are related to the bile acid malabsorption, that's a lot of patients. So I think we're going to continue to see research on this topic, which is very important, and we'll gain a clearer understanding of exactly how often we should be turning to bile acid sequestrants like the cholestyramine or cholestepalam or cholestopal. That's definitely something.

Dr. Chey:

And then small intestinal bacterial overgrowth, or SIBO, is another thing that we think about, or we're talking about a lot, and there's a lot of controversy about whether SIBO is the same thing as IBS or whether SIBO is a completely separate and distinct disease from IBS. The truth is probably somewhere in between, like always. And then other things like disaccharidase deficiency. I'm sure we'll talk about that. That's a really interesting and a really rapidly evolving topic.

Dr. Chey:

But I do want to say one word about the IBS-C group because if you think about it, everything I've said up to this point has been focused on IBS-D and that's pelvic floor dysfunction, and the three of us have had many discussions about this and it's so gratifying to start to see the ship turn in terms of gastroenterologists and even, I dare say, in some cases, primary care physicians, starting to think about that as an explanation for refractory symptoms in patients with IBS-C who don't get better with laxatives. That's primarily where clinicians and patients should be starting to ask questions about this. Possibility is if you have constipation-related symptoms, with or without abdominal pain, and you've tried a variety of laxative therapies and nothing has worked pelvic floor dysfunction or an evacuation disorder the inability to be able to fully evacuate stool from the rectum goes way up on your list of possibilities.

Dr. Riehl:

And that then adds to the team right. So we have pelvic floor physical therapists that are life-changing for patients, and so the team widens a bit with some of our constipation patients. But you bring up such a good point in terms of looking for other options for these patients that are totally suffering.

Dr. Chey:

It really speaks to this point that again, in 2024, it takes a village. Ibs therapy is no longer focused solely on the gastroenterologist, which is, you know, in 1990, the treatment of IBS was almost entirely focused on the gastroenterologist. You know, the gastroenterologist I sort of think of as more now as the captain of the team. The gastroenterologist still plays an incredibly important role, arguably the most important role in terms of coordinating the care between the various stakeholders. But the gastroenterologist in 2024, for the complex or severely affected IBS patient, is sorely inadequate.

Dr. Riehl:

And you make the best point that providing that definitive diagnosis for the patient is really the starting point. They're not going to believe you when you say you know, I've got this GI psychologist you can go talk to. You know, I think you have IBS. It has to be. You have IBS, I have a team that I work with. We will all help you. Let's explore what these options are. I'm confident that we can get you feeling better.

Dr. Chey:

I always say to people too, that when I'm teaching fellows about IBS, I say think about what we say to an IBS patient. Typically, I think you have IBS. It's a condition defined by the presence of abdominal pain and altered bowel habits. The good news is that it's not associated with cancer or other organic diseases. The bad news is we don't know what causes it. We don't know what the best treatment for it is, and you're going to have it for the rest of your life.

Dr. Riehl:

Yay, think about how that would make you feel Woo-hoo.

Dr. Chey:

How could you walk away from that interaction with anything but just despair? Think about this you have IBS. It's a condition for which we have an immensely growing understanding and for that reason and understanding that there are lots of reasons why patients have IBS symptoms, we have a team of individuals that can provide a variety of different treatment options for you. We will use those stakeholders to tailor an individualized treatment program for you and there's a very high likelihood probably a greater than 80% chance that we will be able to make your symptoms more manageable. What a different message, right.

Dr. Riehl:

Same disease. Yeah. So for any listeners out there, if you've heard anything but that very expert delivery of the diagnosis, think about Dr Chey in your head when you think about your IBS diagnosis. There's an incredible amount of uncertainty that comes if you don't receive a diagnosis like that. Certainty that comes if you don't receive a diagnosis like that. And so we do want to instill a lot of hope for people that you know we can help you live well with IBS. So thank you for that, Dr. Chey.

Kate:

Absolutely. We need a dream team approach, right? We talk about that a lot in Mind your Gut. It's not just one person like you know, it's a team sport Moving just into mimickers. Again, I wanted to talk because there's a lot sport Moving just into mimickers. Again, I wanted to talk because there's a lot of sort of misinformation about parasitic infections but then sometimes parasitic infections can mimic IBS. What type of parasitic infections do you think about that might mimic IBS-D and when or what would be some things that you would think about. That would you know. You'd say, oh, this might be a consideration in this particular patient.

Dr. Chey:

In the United States, the big one to really think about and consider and even identify like we probably identify at least a few patients a year with Giardia. Giardia is a very important parasitic infection to be aware of, particularly in certain parts of the country Like, for example Megan and I are from Michigan. Well, in Northern Michigan and some of the lakes there will be outbreaks of Giardia, so it can present with all the symptoms that seem identical to IBS. Most of the time, by the way, though, the symptoms will be much more severe, but occasionally you'll get a patient who, for whatever reason, doesn't express the full-blown illness and has symptoms more akin to IBS. So, as part of an early evaluation, in places where there is the possibility of endemic parasitic infection, it's reasonable to do a GI PCR, which would include a screen for Giardia.

Dr. Riehl:

What do you think about the patients that come in with the wide-sweeping stool studies that they've sent in stool to a company and it's anxiety-provoking. But, as an expert gastroenterologist, tell us a little bit about what patients may or may not be getting from that.

Dr. Chey:

So I get asked this a lot and I get asked this a lot by patients who bring me those reports, and conceptually the concept is really interesting and I think potentially at some point in the future may be actionable. Right now the problem is that a lot of the microbiome analysis, the metabolome analysis, is not adequately validated and really don't know how to interpret it, and that's true too of a lot of proteases. There's a whole wide range of different things that people are testing for in stool now, by the way, all founded in conceptual models which could make sense to IBS, but not necessarily human studies that make clear that that kind of testing is valuable to exclude this disease or that, or certainly to identify patients that would benefit from this supplement or that, which is usually how this works. I hope this doesn't come off as too inflammatory, but one of the business models that goes unspoken, of course, is that you do the testing and then you order supplements from your own shop for which there's a profit margin.

Dr. Chey:

I'm not saying that that's the only reason why providers do this. I know for sure that's not the case but it does create a bit of an intrinsic conflict of interest. So, bottom line right now, there are things in those tests which are valuable. So for example, iron studies, certain studies of vitamins can be helpful, but a lot of it, and in particular a lot of the stuff that's really foundational to the testing right now, I think in, at least in my mind has not been adequately validated. So the microbiome metabolome analysis, those types of things I think could be valuable, but I don't think we know that they're valuable yeah so if you're coming in with that big supplement list and maybe they've been on it for a month or two.

Dr. Riehl:

One thing that we talk about is it probably isn't the right thing for you and we have to pivot. So before shelling out more money, it's always a good idea to check in with a gastroenterologist. A little further about that.

Kate:

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Speaker 4:

This podcast is brought to you by QOL Medical, the manufacturer of Sucraid sacrosidase oral solution. Sucraid is the only FDA-approved enzyme replacement therapy for the treatment of CSID. Patients who have CSID cannot tolerate sugar sucrose, which can lead to unresolved IBS-like symptoms. After you've ruled out lactose and celiac, consider CSID. Sucraid is an enzyme replacement therapy for the treatment of genetically determined sucrase deficiency, which is part of congenital sucrase isomaltase deficiency. Csid Sucraid may cause a serious allergic reaction. If you notice any swelling or have difficulty breathing, get emergency help right away. Tell your doctor if you're allergic to have ever had a reaction to or have ever had difficulty taking yeast, yeast products, papain or glycerin glycerol. For more information and to see FDA approved labelling, go to Sucraid. com.

Dr. Riehl:

It's here our book baby, Mind Your Gut: The Science-based Whole Body Guide to Living Well with IBS, is officially available in March 2024. Mind Your Gut combines diet and behavioral interventions for a full toolbox of therapeutic options for IBS.

Kate:

That's right, Megan. We poured our heart and our brain into creating this book that provides so much valuable information, from the link between the gut, brain and food, the impact of stress, overload, and everyday tips to help to better manage life stressors. Easy to implement, symptom-specific interventions, nutrition remedies to calm your gut and maximize gut health, and all about IBS mimickers and so much more you won't want to miss this opportunity to live well with IBS.

Dr. Riehl:

The book is available in our show notes as well as at all major book retailers, so we're going to pivot also to an area of research that you've certainly been doing a lot in. When might you consider sucrose isomaltase deficiency, and how common is this? What are the red flags that we're looking for?

Dr. Chey:

Yeah. So right now, there's increasing focus on sucrose isomaltase, and our group will definitely take some credit or fault for that. People are talking about it. I think it's a valuable topic for us to be discussing as a scientific community, but there are a lot of unanswered questions, and we'll get into that in a second. What I do want to do, though, is to say that one thing that I've learned from doing research in this field is that we probably need to broaden the way that we look at. We probably need to broaden the way that we look at disaccharidase deficiencies, rather than just sucrose isomaltase deficiency. So, in other words, there are a whole bunch of different disaccharidases.

Dr. Chey:

The one that everybody knows the most is lactase, and remember that lactose is part of the FODMAP family, so it's been acknowledged as a potential trigger for IBS symptoms for many, many years. This is not new information. Now, sucrose is not part of the FODMAP approach, which is one of the reasons why it's such an interesting part of the discussion as we move forward, because, intuitively, since sucrose is not part of the FODMAP family at least the traditional FODMAP family that we think about in the low FODMAP diet if a patient does not respond to the low FODMAP diet, it would make sense that there's an increased likelihood of sucrase deficiency, sucrase isomaltase deficiency and therefore what happens is sucrose, which is typically not a FODMAP, when you have that enzyme, in the absence of the enzyme, becomes a FODMAP. In other words, it's exactly the same as if you don't have lactase. And in fact, in a post-hoc analysis from one of our randomized controlled trials, that's exactly what we found is that there was a more than two-fold increased likelihood of response to the low FODMAP diet if you didn't have mutations of the sucrose isomaltase gene. So that was an interesting tidbit of information.

Dr. Chey:

We just finished a study where just this can be an oral presentation at Digestive Diseases Week in May, reporting data from a large-scale prospective study using disaccharidase assay to determine the prevalence of different disaccharidase deficiencies in the US. And what we're going to report is that sucrose is a multi-ase deficiency is present in around 8.5% of isolates, which is much higher than we thought previously. Think about this. Remember we said before celiac disease is less than 1%. We look for that in every IBS patient. Sucrose is a multi-ase deficiency is present in 8.5% in over 200 patients that we enrolled from all over the United States.

Dr. Chey:

By the way, in fairness, you have to say this. Does that mean, like, for those 8.5% of individuals that have sucrose isomaltase deficiency, does that mean that that is responsible for their symptoms, similar to what we talked about with bile acids? Not necessarily so. It can be true and unrelated, right? So that's one of the next things that we really need to study.

Dr. Chey:

We need to understand when is a duck a duck? I don't think we know that right now. I think the other thing to realize that complicates this discussion and this is why research is so much fun is because you answer one question but you create 10 others. Realize this is that sucrose isomaltase deficiency, the majority of the time, occurs with other enzyme deficiencies, so 8.5% is not patients that have just sucrose isomaltase deficiency. Those are people that have palatinase deficiency, lactase deficiency, so a lot of the patients that have SID have other disaccharides deficiencies, and the degree to which you can fix one and make the symptoms better is not clear. So we have so much to learn, but what's fair to say is that disaccharidease deficiencies in general should be on our radar screen. It should be something that we're thinking about as an important trigger for symptoms in patients with IBS.

Dr. Riehl:

How do you test for that and what might be a treatment?

Dr. Chey:

So right now the gold standard test is biopsies from the proximal small intestine and then sending them to a specialty laboratory to determine the level of enzyme activity in association with the different disaccharidases, and there are sort of international standards that have been established for the different enzymes. People also talk a lot about doing breath tests to identify patients with sucrose isomaltase deficiency. Unfortunately, those are much less well-studied or validated. In fact, I'm telling you that our data is the first large-scale data in adults from the United States using disaccharides assay large-scale data in adults from the United States using disaccharide assay. So again, one of the things we need to do next is try to really more carefully validate the other tests that might be used to identify these patients in clinical practice. Part of our abstract that we're presenting at DDW did evaluate a C13 sucrose breath test and unfortunately found it to not be terribly accurate. So we'll have to see if others replicate that data and I'd like to see additional testing with other forms of breath tests, more traditional sucrose breath testing.

Kate:

Just a quick question when you looked at these individuals with IBS and checked their Dysac assays, were they IBS-D? Predominant Is diarrhea, sort of the like ooh, these patients might have it versus someone with constipation. Or I'm just thinking red flags for someone that might be thinking, hey, I might have sucrose isomaltase deficiency.

Dr. Chey:

That's a really important question. I'm glad you asked that because I should have made that more clear. Our study was in patients with IBS-D symptoms by the Rome criteria. So what we found in preliminary sort of observational retrospective studies is that the patients to worry about with dissect deficiency definitely had diarrhea. That's sort of the hallmark symptom that people have always talked about for many decades. But what we also found in our research was that abdominal pain and bloating were just as common as diarrhea. So that's why we focused on IBS-D, because if you think about it, that's IBS-D, it's abdominal pain, bloating and diarrhea. So the prevalence of SID is 8.5% in IBS-D patients by Rome criteria.

Dr. Riehl:

Okay, how about bile acid malabsorption of bile acid diarrhea? When might you consider this as part of the clinical picture?

Dr. Chey:

Yeah, there's been a lot of chatter about this as well, and I mentioned earlier that there's data, predominantly from the Mayo Clinic, suggesting that anywhere between 20-25%, maybe even up to 30%, of patients with IBS-D have evidence of bile acid malabsorption. Again, it doesn't prove cause and effect necessarily, but it is measurably abnormal in patients with IBS-D. That's sort of all comers Patients in which you should think about it even more so are after cholecystectomy. So if a patient has had a previous cholecystectomy, independent of whether they have abdominal pain or not, if they have diarrhea you should be thinking about bile acid malabsorption.

Dr. Chey:

There's also, interestingly, a relationship between SIBO and bile acid diarrhea, because bacterial overgrowth so bacteria in the small bowel, can deconjugate bile acids prematurely in the small intestine, converting bile acids to a form that are more likely to induce diarrhea primary bile acids and so therefore patients with SIBO are more likely to get bile acid diarrhea Also. The last category that is really important, particularly for listeners that are having problems with diarrhea is if you've had surgery to remove the last part of your small intestine, the ileum, that actually is a huge setup to develop bile acid diarrhea because in the ileum there are receptors called IBATs ileal bile acid transporters that reabsorb bile acids and if you remove the ileum, you remove those IBATs and you're not able to reabsorb the bile acids before they get to the colon where they induce secretion of fluid and stimulate contractile activity in the colon that causes diarrhea.

Dr. Riehl:

What might a patient look for for treatment for that?

Dr. Chey:

Right now the primary treatment for bile acid diarrhea is to give the patient a bile acid sequestrant. This is a resin that absorbs excess bile acids in the fecal effluent and in that way reduces the burden of bile acids that get to the colon. That can cause diarrhea.

Dr. Riehl:

So another example of it may be medication, it may be lifestyle, it may be nutrition, but figuring out more of that root cause is really important because you can't keep going without that medication. It's really needed.

Dr. Chey:

No question about it. You can see, as we're talking about this, we're slowly, at a snail's pace, moving towards more of a precision medicine kind of model, which is really where we want to go right. We really want to move from this sort of empiric treatment based on a patient's symptoms to we do this test to determine whether the patient has this disease and for that disease it's this therapy. By the way, patients that listen to me talk about this always get really excited and think well, why is my doctor doing this right now? Well, to a large extent, docs don't have the capability or the training to do this right now. So this is very much a story in evolution. It is getting better. It's going to get even better over time, but it will take time.

Dr. Riehl:

Okay, so one of our last IBS potential mimickers you've mentioned it small intestinal bacterial overgrowth. It's complicated, right, and so where do you think we are right now in terms of the patients that Google this and bring this to your office and they're curious about it? What are you looking for and how might you treat it in your clinic?

Dr. Chey:

Well, there's little doubt that this exists. There's little doubt in my mind that there are patients that have a transposition of bacteria into the small intestine that leads to a variety of clinical consequences, and those clinical consequences can oftentimes overlap significantly with IBS, particularly IBS-D, but in some cases perhaps IBS-C too. We can talk about that. The fundamental way that we are looking at small intestinal bacterial overgrowth at the current time, I think in five years will be almost entirely antiquated. So you know, one of the committees that I'm sitting on right now is called the Luminal Microenvironment Committee for the Rome Foundation, microenvironment committee for the Rome Foundation. So we're writing the chapter for the Rome 5 compendium on the importance of the luminal microenvironment, and one of the things that we're spending the most time talking about is the microbiome and the small intestine and large intestine and SIBO in particular, and we've had a lot of discussions about this a group of key opinion leaders from all over the world that know a lot about this. Literally, this is what they do in terms of research in their clinical practice, and I think there's an increasing mindset I've been saying this for many years, by the way.

Dr. Chey:

I'm glad that it seems to be getting more popular is that defining SIBO purely on the basis of quantity of bacteria in certain parts of the small bowel. That may very well be part of the definition, but it's probably missing a big part of the issue at hand, which is what bacteria are there and what are they doing. So it may be the constituents and the metabolomic consequences that are as or more important than the actual quantity of bacteria. And so right now we're really just at a stage where we're just defining what are the bacteria that are present in patients with SIBO and what are they doing compared to healthy controls. So we're very much at an early stage in this discussion, but I bet the way it's going to settle out is that it won't just be by quantity of bacteria that we're defining SIBO. So we're still at very early stages.

Dr. Chey:

But, that said, I do want to give a shout out to Mark Pimentel, because Mark really has suffered the slings and arrows of thinking differently and you know, while he and I have certainly had our disagreements in terms of you know, the way that we look at the world and look at SIBO and IBS, we wouldn't even be having this discussion if it weren't for Mark Pimentel. You know he's a true leader, you true leader in terms of research in this field and a trailblazer, and, again, definitely has paid his dues for thinking differently. I do want to just give him credit for that for sure.

Dr. Riehl:

Our listeners are in for a treat because we're going to have a really, I think, provocative conversation with Dr. Pimentel in an upcoming episode.

Kate:

Oh, yeah, thanks for the teaser. Bill yes, absolutely, he is a maverick and I'm glad you see it that way as well, because I know he's had a lot of criticism and he just keeps fighting and gets scrappy and is showing a lot of really interesting data. So gets scrappy and is showing a lot of really interesting data.

Dr. Chey:

So, yeah, and he's been right a lot more than he's been wrong. I mean, I think, if you really put things on the scale, yeah, he's been wrong about some things, but he's been right about a whole bunch of things and you know, and I think you have to give him credit for that I mean the whole refection story and the way that we treat a subset of patients with IBS. I mean you have to give more credit for that, that's science, right trial and error. That's right.

Kate:

So if you've tried traditional testing and treatments for the symptoms you're experiencing without any benefit, don't be afraid to ask your physician about some of the IBS mimickers we have discussed today on this episode. They can help you, and the more you know, the more you're able to advocate for yourself.

Dr. Riehl:

Yeah, you know, as we've talked with Dr Chey today, he points out that diagnosis is key and, as we've all identified in so many GI conditions and really with gut health generally, that a lot of times people need a dream team. And that dream team multidisciplinary, patient-specific, really is such an incredible importance in really getting you down that road of improving your symptoms, and especially with mimickers, where you might think you have one thing and it actually turns out to possibly be something else or something in addition. So when we think about the dream team, as we've talked about, the addition of an RD can provide really necessary nutrition therapy which can be a game changer, especially with a diagnosis such as Celiac disease. And in some cases not only does a GI psychologist join the team to provide brain, gut, behavioral therapies and these therapies can improve symptoms, coping, social support, but we can also dive a little deeper into aspects of grief and, as we've kind of talked about today, when you have a diagnosis and again I'll just use Celiac disease as an example where really the treatment is a restrictive diet, it's saying goodbye to gluten and we want to normalize that.

Dr. Riehl:

Grief can be a part of that and some of the aspects of grief that come with this are just detection and decision fatigue. So does something have gluten? Where do we find it? What can I eat? And this can really happen across the lifespan, from parents that are helping their child navigate a diagnosis like this all the way up through going off to college and then living on your own. So keep in mind that you are not alone with these diagnoses, and we really want to stress the importance of that. And we really want to stress the importance of that. Now, as you all know, gut health matters. Our dear friends, and so many good things in life can boost our gut health, from the foods that we eat, to the people that we spend time with, to the events that boost all of our endorphins, and nothing will boost endorphins like what we are going to share with you next. So, Kate, do you have some news for us?

Kate:

Well, we have just had such overwhelming positive response to the Gut Health Podcast and we really appreciate all of your support. We're just so excited. It's been amazing, okay, okay, so should I tell them? You should tell them all right.

Dr. Riehl:

We've decided to expand our team and we thought that we could use a little extra help with the podcast content and marketing. So please join Kate and I with a big hello to yes, we have a new team member.

Kate:

This is Mabel June. You know she might be a little unqualified, I don't think so.

Dr. Riehl:

I mean she's already diving into the microphone.

Kate:

I mean that's right, I think you know what she's going to ramp up in no time, right now she literally is trying to get the headphones on.

Dr. Riehl:

She wants her own microphone, so we're going to have to get another Shure MV7 because that's what we use around here. But she is looking like she is ready to go for episode four and with all of our hearts bursting and already excited to hear about Mabel's first month during our next episode. Bill, we thank you for joining us. We certainly learned a lot as we wrap up this episode. What is something that you prioritize when it comes to your overall health and wellness?

Dr. Chey:

Increasingly as I get a bit older, it's really time with my family. When I was younger I didn't fully appreciate how important that is. But as you get older I think everybody realizes time really speeds up. What you think is like six months down the road is just around the corner. It just literally comes up on you out of nowhere. So prioritizing those moments that you can spend with your family I think are so incredibly important.

Kate:

Love it. A big thanks to our guest, Dr. Chey. We value your expertise and willingness to spend some time with us and our audience on our podcast. Next up we are talking about small intestinal bacterial overgrowth in the small bowel microbiome with Dr. Mark Pimentel from Cedars-Sinai in Los Angeles.

Dr. Riehl:

So make sure you subscribe, follow and like The Gut Health Podcast. Your support means the world, our friends. Thank you for joining us as we grow this gut health community. We hope you enjoyed this episode and don't forget to subscribe, rate and leave us a comment. You can also follow us on social media @The Gut Health Podcast, where we'd love for you to share your thoughts, questions and experiences. Thanks for tuning in, friends.

People on this episode

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Kate Scarlata

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Megan Riehl

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