Irritable bowel syndrome (IBS) is a lot more common than you might think. In fact, it affects 1 in 10 people globally. Yet there are still a lot of questions about why it occurs and how best to treat it.
Could new research connecting gut health to mental health help us unravel its mysteries?
In today’s short episode of ZOE Science & Nutrition, Jonathan and Dr. Will ask: What exactly is IBS, and how does it connect to our brains?
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Referenced in today's episode:
FODMAP Diet: What you need to know from Johns Hopkins Medicine
Large-scale genetic study reveals new clues for the shared origins of irritable bowel syndrome and mental health disorder from the University of Cambridge
Irritable bowel syndrome: A chronic sequelae of acute gastroenteritis from Gastroenterology
William Olser: Biographical overview from the National Library Of Medicine
IBS: What you need to know from the National Center For Complementary and Integrative Health
Irritable bowel syndrome (IBS) overview from Johns Hopkins Medicine
Episode transcripts are available here.
Is there a nutrition topic you’d like us to explore? Email us at email@example.com and we’ll do our best to cover it.
[00:00:00] Jonathan Wolf: Hello and welcome to ZOE Shorts, the bite-sized podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolf. Today I'm joined by Dr. Will Bulsiewicz, and today's subject is irritable bowel syndrome.
[00:00:18] Dr. Will Bulsiewicz: IBS, Jonathan, it's more common than you might think, but still very misunderstood.
[00:00:22] Jonathan Wolf: Why is it so common Will? And yet no one seems to really understand what it is. In fact, what is it exactly? And how is it different from bowel diseases?
[00:00:32] Dr. Will Bulsiewicz: Those questions are complicated to answer. As it turns out, there's a mysterious mind's body connection when it comes to your old bowel syndrome.
[00:00:40] Jonathan Wolf: Intriguing. Let's get into it.
[00:00:44] Dr. Will Bulsiewicz: Okay, Jonathan, let's jump in our DeLorean for a moment and we're going to travel back to, of all places a medical school in the late 18 hundreds. Why? That's when IBS was first discovered. It was a Canadian physician, uh, a very famous physician, someone who I learned about in medical school. His name is Sir William Osler. If you could just picture a big white mustache in the pocket watch, that's kind of the imagery that we have. So he was one of the best known physicians at the time, and in 1892, he coined the term mucous colitis. What he was referring to was a digestive condition that involved a combination of abdominal colic or abdominal pain and the passing of mucus in this stool. Today, this has been recognized as being the early definition of irritable bowel syndrome.
[00:01:35] Jonathan Wolf: And I guess the fact that it was so long ago explains why this name Irritable Bowel Syndrome sounds a bit like an eighties rock band. I'm assuming that since then we've learned a lot. So what exactly do we think IBS is today?
[00:01:53] Dr. Will Bulsiewicz: It's a group of symptoms that happen together, and so basically you have to start with having abdominal pain, and that abdominal pain will occur alongside some sort of change in the bowels. So it could be diarrhea, constipation, or a combination of both. Now, the symptoms of IBS may change over time, but IBS is often lifelong. This is not something that you can just cure with antibiotics or something like that. But it's something that you can manage. It's something you can manage to the point that it doesn't necessarily affect your quality of life. IBS is interesting because although it's a bowel disease, it doesn't. increase your risk of developing bowel cancer or other bowel related issues. The mystery around IBS is that even though this is so common, we don't know exactly what causes it. Although I will say we have some strong clues that we'll talk about today.
[00:02:43] Jonathan Wolf: it's really common, right? So we looked at the latest data and IBS affects about one in 10 people worldwide. In North America, it's estimated that 10 to 15%. Of the population have it. It's less prevalent in people aged over 50 and it's also more likely to affect women than men. As some listeners may know, I suffered from fairly mild IBS in my twenties, uh, and into my thirties. So it's something that I have personal experience with and is quite close to my heart. So can we start will by looking at some of those classic IBS symptoms and I think that those often consist of sort of this stomach pain combined with a change in bowel movements. In other words, not sort of the regular movement that, you know, we all would like to be having when we go to the toilet.
[00:03:34] Dr. Will Bulsiewicz: Yeah, that's exactly right. And I think we have to start by saying that abdominal pain is a core part of this diagnosis. So if you don't experience any abdominal pain or discomfort, Then it's not IBS, although you may still be experiencing diarrhea or constipation. It can come with different experiences for different patients. So for example, some may experience discomfort or pain that's sharp and intense. Others have these cramps that sort of seem to come in waves, like it builds up and then relieves, or others have symptoms more like bloating or even a burning discomfort. So individuals with IBS, they can have other coinciding symptoms like gurgling of the stomach or the feeling of incompletely evacuating their bowels after a bowel movement. Or even the passage of mucus in the stool, which is what Dr. Osler was referring to.
[00:04:26] Jonathan Wolf: So Will, I mean, none of these things sound like fun. We've also discussed a lot of different digestive health issues on the show, and some of those symptoms overlap with some of the things you were just describing. So if a listener is listening to this right now, you know, how can you tell if these symptoms add up to IBS? Could you maybe talk us through how it's normally diagnosed?
[00:04:48] Dr. Will Bulsiewicz: Sure. So we have to start with the basics, which is that IBS is a pattern of symptoms and we call it irritable bowel syndrome. The word syndrome is really key, and that's because we have to use criteria to diagnose IBS. There's no specific blood test or x-ray or poop test to diagnose IBS. This is actually the key in a way Jonathan, which is that there's no definitive test. So ultimately, in order to diagnose IBS, you have to fulfill specific pattern-based criteria. The criteria that we used are called the Rome criteria. Now, this has been revised. It started with Rome one. Now we're up to Rome four. So this is the fourth version.
[00:03:34] Jonathan Wolf: What does the Rome four criteria then say?
[00:05:32] Dr. Will Bulsiewicz: Okay, so in order to qualify under the criteria, you need to have first recurrent abdominal pain at least one day per week in the last three months. Then in addition to that, you need to have at least two specific changes that relate to your bowel movements. One is that there's an association of your symptoms with your bowel movement. For the majority of people who have IBS, Jonathan, they will experience improvement of their symptoms after they go to the loo. A second possibility is a change in the stool frequency. And then the third is a change in stool appearance. So basically changes with the bowel movements, changes in stool frequency, changes in stool appearance. You need at least two of those.
[00:03:34] Jonathan Wolf: And are there different types of IBS?
[00:06:19] Dr. Will Bulsiewicz: Indeed, there are, there are four types actually. So IBS D stands for diarrhea. Meaning that the abnormal bowel movements are usually diarrhea. Then we have IBS C
[00:06:35] Jonathan Wolf: I think I can guess this one. I'm guessing this means constipation, right?
[00:06:39] Dr. Will Bulsiewicz: That is correct. Then there's IBS M for mixed, which is of course a mix of both diarrhea and constipation. And then the last one, which is actually quite, quite rare is IBS U, which means unclassified. And these are patients who haven't met the technical criteria for IBS in terms of diarrhea or constipation. So they really can't be slotted into one of these other three types.
[00:07:06] Jonathan Wolf: Got it. Alright, so take me into the doctor's office, like your office during one of these diagnoses.
[00:07:12] Dr. Will Bulsiewicz: Well, so the first thing is that the clinician's going to start with a comprehensive history and physical examination. This is an opportunity for the patient to really describe these symptoms in full detail.
[00:07:23] Jonathan Wolf: Now, pain, diarrhea, and constipation. These are also symptoms of other conditions which you've talked about on previous podcasts. So what's the risk of misdiagnosing here?
[00:07:33] Dr. Will Bulsiewicz: Yeah, that's an excellent point, Jonathan, because you know, one of the important things from my perspective as a medical doctor is to make sure that you're not missing something else. There are a number of different conditions that can masquerade and sound just like ibs, and yet if it's something else, you're not, you're not treating your patient appropriately until you make that diagnosis and then target that in terms of your treatment. So one of the things that doctors will do is they'll look for red flag symptoms, and this helps the doctor to realize that there may be something more going on here beyond just run-of-the-mill irritable bowel syndrome. The red flag symptoms include unexplained weight loss, anemia, seeing blood in the stool, having diarrhea in the middle of the night, having progressive and intensifying abdominal pain. Then we also get a little more cautious in people beyond age 50. Or who have a family history of inflammatory bowel disease or bowel cancer. Because in those cases you just don't wanna miss those possibilities.
[00:08:37] Jonathan Wolf: I know that in my case, and this is now almost 30 years ago, the doctors did a lot of investigations to make sure that I didn't have any bowel diseases. I remember it was an enormous relief to discover that it wasn't cancer, which I'd been really scared about, or some major bowel disease. Now, what are some of the alternatives to IBS that a doctor might be looking for?
[00:08:58] Dr. Will Bulsiewicz: So there are a number of possibilities. Of course, the doctor's going to individualize what they're doing to what the patient is reporting to them. But some of the ones that I would classically think about include chronic infections, so things like c diff infection or giardia. I always would have a very high level of suspicion for the possibility of celiac disease, because it can sound just like IBS. You have to think about food intolerances. So it could be lactose intolerance, it could be a FODMAP intolerance or a sucrose intolerance. You could also have small intestine bacterial overgrowth. People know this as SIBO. Or you could have an inflammatory bowel disease, which includes conditions like ulcerative colitis, Crohn's disease, or something called microscopic colitis.
[00:09:40] Jonathan Wolf: Could it in fact be as simple as chronic constipation?
[00:09:44] Dr. Will Bulsiewicz: It could. it's interesting because not everyone who has constipation has IBS, but everyone who has IBS C has constipation and there are even several patterns of constipation that can masquerade as other forms of IBS.
[00:10:03] Jonathan Wolf: Sneaky. So how does that work Will?
[00:10:06] Dr. Will Bulsiewicz: I'm specifically thinking about IBS D or even IBS M, the mixed IBS, because I actually think in many cases these are constipation. Let me give you a quick example, Jonathan. Someone could have zero bowel movements for several days in a row. And then all of a sudden they have this one day where the first bowel movement comes and it's formed, but then they keep having more and more bowel movements as the day goes on and the bowel movements, they get looser and looser to the point of being water. So this person, they think they have diarrhea, but from my perspective, this is actually constipation.
[00:10:44] Jonathan Wolf: So they're sort of backed up for days until they're sort of effectively set to explode.
[00:10:48] Dr. Will Bulsiewicz: Yeah, to put it delicately, Jonathan.
[00:10:51] Jonathan Wolf: Okay. Not a, not a technical term. Okay, so coming to my own experience, I was diagnosed with IBS in my early twenties, so little more than 25 years ago after I had been very sick with glandular fever, which is mononucleosis for in the States, for sort of six months. At that time, I remember this really well, none of the gastroenterologists that I saw thought that any of the microbes in our gut mattered at all. This is basically pre the time when the microbiome had been discovered. So at the time, they were basically convinced that IBS was probably largely caused by stress, and that basically if you could get yourself really relaxed, then probably this would solve most of this problem.Is that a real thing still today or is that a myth? From a time before we understood the importance of our gut bacteria and just sort of the complexity of what was going on inside our gut?
[00:11:44] Dr. Will Bulsiewicz: When it comes to the connections between stress and the manifestations in our gut there is very clearly a psychological element to it. In fact, Jonathan one study found that patients with IBS reported more lifetime and daily stressful events than control groups.
[00:12:03] Jonathan Wolf: That's interesting. And Will, does this mean that stress is a cause or just a result of an unhappy gut? Because you know, again, thinking back to when I had this, if you've got a really bad stomach and it may be impacting your quality of life, you're going to feel stressed as a result of this. Which way round is it?
[00:12:20] Dr. Will Bulsiewicz: Looking at the data, stress has been linked to the onset of symptoms, and then the symptoms improve when the stress is gone. So there's that. Another study found that patients with IBS showed increased levels of anxiety, depression, and phobias. So I think that there's sort of a little bit of both going on here, Jonathan.
[00:12:41] Jonathan Wolf: Which I have learned in everything to do with the human body is common. It's never as simple as one thing. So the team who looked at this found a recent study, a very recent study from 2021 of over 50,000 people with IBS around the world, and the researchers in that study found that people with IBS were more likely to have anxiety. When I think back to when my symptoms were really bad, which is sort of right at the beginning of my early twenties, I was definitely, maybe not medically depressed by this, but definitely, depressed by this in sort of common language. I thought what was interesting is the study also found that people with both IBS and anxiety were more likely to have been treated frequently with antibiotics during childhood. The study authors suggested that repeated use of antibiotics during childhood might increase the risk of IBS and anxiety by altering the normal gut bacteria, which in turn influences nerve cell development and mood.
[00:13:35] Dr. Will Bulsiewicz: The team was very careful though, to say that this doesn't necessarily mean that anxiety causes IBS symptoms or vice versa. It's just that these things are very much interconnected, it's hard to separate them.
[00:13:45] Jonathan Wolf: I know one of the things I was amazed to discover is this huge amount of nerves and immune system control in our gut, right? So actually the brain and the gut, they really are linked. It's not just one of those things that people say.
[00:13:58] Dr. Will Bulsiewicz: Oh, a hundred percent.
[00:14:00] Jonathan Wolf: So Will, we've gone over what IBS is, what it does and the role that stress and anxiety might play. What about how to manage symptoms? If any of our listeners are saying I think I do have ibs, or Indeed I've been diagnosed with it.
[00:14:13] Dr. Will Bulsiewicz: Yeah, so first of all to those listeners, you have to understand treatment is always gonna be individualized. So it's a little bit hard to completely generalize when you know IBS D and IBS C are different things in terms of how you attack them. But there are some general rules that we can use, and that's what I wanted to address today. Some patients see improvement in their symptoms very quickly if they take these simple steps. Cut out caffeine, alcohol, and spicy and fatty foods.
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[00:14:43] Jonathan Wolf: That's funny. I remember being told very specifically to cut out broccoli.
[00:14:48] Dr. Will Bulsiewicz: Well, that's discriminatory against broccoli but nonetheless, there is also the concept of the low FODMAP diet, Jonathan, which is usually a secondary thing.
[00:14:57] Jonathan Wolf: Tell us what a low FODMAP diet is Will.
[00:14:59] Dr. Will Bulsiewicz: FODMAP is a very nerdy thing standing for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.
[00:15:08] Jonathan Wolf: That's a real mouthful, if you'll excuse the pun.
[00:15:10] Dr. Will Bulsiewicz: It basically means different types of sugar that the small intestine struggles to absorb. The idea is that you will temporarily reduce these foods, or temporarily eliminate these foods so that you can gather an understanding of what's happening with your body.
[00:15:28] Jonathan Wolf: What are the sort of things that you would cut out if you were doing this?
[00:15:30] Dr. Will Bulsiewicz: Um, you may start with things like milk and ice cream, wheat, beans, lentils, even some fruit and veggies like onions and apples and garlic. Again, all temporary, but you can also start with a much more limited version where you would temporarily restrict dairy and gluten containing products.
[00:15:48] Jonathan Wolf: And what about supplements or anything else that we can take for IBS instead of effectively excluding things?
[00:15:55] Dr. Will Bulsiewicz: So there's been mixed evidence but there are some that stand out in terms of potentially being helpful. One is peppermint oil. peppermint oil seems to really help in terms of abdominal discomfort and bloating. The menthol seems to have a soothing effect on the small intestine. There was also a 2014 paper showing that probiotics can improve IBS symptoms. Now in this paper they said the quality of the existing studies is limited, and as a gastroenterologist I would agree with that. Probiotics are not the solution for everyone. But when you find the right probiotic, it can actually be very helpful for many people. The last thing that I would say is that I've had great success with some fiber supplements, specifically cilium husk or soluble fiber supplements, Jonathan.
[00:16:42] Jonathan Wolf: Amazing. So it's nice to know there are some things that one can try. now away from dietary measures, I also heard that acupuncture can help.
[00:16:50] Dr. Will Bulsiewicz: It's interesting Jonathan, a 2009 clinical trial of 230 participants with IBS. Found that those who received acupuncture actually did better than those who did not. Another thing you could try is mindfulness. This can be very helpful to some people, this could be as simple as doing breathing exercises. I've had great success using something called cognitive behavioral therapy or CBT. Now this is something I usually use in addition to medical treatments and of course we should mention that there are medications that are commonly used for IBS. Now, I'm not a fan of just medications, I think we should be including these other things, but there are some that are really effective. Something that's interesting is that we have sort of repurposed many of the medications that were developed to treat depression to treat irritable bowel syndrome, but we use them at a much lower dose. So when it comes to medicines, once again, you have to make choices based upon the person's individual needs.
[00:17:49] Jonathan Wolf: So Will, what if someone's listening to this, they've been diagnosed with IBS, they've changed their diet, they've changed some of their treatments, but things are still not getting better?
[00:17:58] Dr. Will Bulsiewicz: You know, this is such a big topic and there's so much that we could talk about here, Jonathan, but one of the things that I would say is that if you have your bowel syndrome, or frankly even if you don't, we should all be orienting our diet and lifestyle towards supporting the gut microbiome. Because ultimately the gut microbiome plays a central role in the development of IBS. I think that we've made that clear in our conversation today, and therefore our solution should include centrally a focus on improving and elevating the gut microbiome. Now, there are some people that I've taken care of through the years, Jonathan, who have literally tried everything and these people are desperate and they're just not getting better. Their quality of life is in shambles and when this is the case, typically my first approach is to ask the question, is this really IBS? Because if you can identify an alternative, that may be the solution to fixing the problem, that may be why you're not getting better. Another thing that people should consider is the power of the brain gut connection. Throughout my career, Jonathan, I have witnessed this so many times where the connections between our digestive issues and our mood. Having a history of trauma can actually be fueling these problems. So it's interesting, sometimes the solution isn't actually just treating the gut. Sometimes the solution is also addressing that psychological factor that's holding you back.
[00:19:26] Jonathan Wolf: So Will, coming to the conclusion here. Is IBS mainly in our heads, as some people have suggested?
[00:19:32] Dr. Will Bulsiewicz: Absolutely not. That's to me absurd as a gastroenterologist. But you know, what we do know is that there is this brain-gut connection that is really relevant to irritable bowel syndrome and when we're approaching this issue, we have to start by looking at the symptoms that are used to diagnose IBS. Follow the Rome four criteria and make sure that those symptoms are not actually some other condition that is masquerading as IBS. So we have to think about these other things like celiac disease or inflammatory bowel disease. Now, stress is a factor here, and there are links to anxiety. So let's bear in mind the power that exists between the gut and the brain and how they're interacting and when it comes to developing our treatment strategies. Ultimately, I sincerely believe that dietary modification should be a part of the approach for every single patient who has this issue that we should strive to elevate and improve the health of our gut microbiome. But, also when we need medicine or when we need supplements we shouldn't be bashful about that. We should take advantage of those possibilities to improve our symptoms and our quality of life, and don't lose sight of these other things that can be beneficial like diaphragmatic breathing. Acupuncture or cognitive behavioral therapy.
[00:20:52] Jonathan Wolf: Well, thank you, and I can tell that we could have spent five times longer on this, so I'm sure this is a topic we'll come back to in the future. If, based on today's program, you'd like to try ZOE's personalized nutrition program to improve your health, and maybe manage your weight, you can get 10% off by going to joinzoe.com/podcast. I'm Jonathan Wolf.
[00:21:11] Dr. Will Bulsiewicz: I'm Will Bulsiewicz.
[00:21:12] Jonathan Wolf: Join us next week for another ZOE Podcast.