The Gut Health Podcast

Small Intestinal Bacterial Overgrowth (SIBO) + the Small Bowel Microbiome with Mark Pimentel MD

• Kate Scarlata and Megan Riehl

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Got excess intestinal gas, bloating and GI distress? Expand your knowledge on the topic of small intestinal bacterial overgrowth (SIBO) with our guest expert gastroenterologist, Dr. Mark Pimentel. Dr. Pimentel is a true maverick in the field of GI motility and the complexities of the small intestinal microbiome.  His team has truly helped pave the way to our understandings of many complex GI conditions, including SIBO and irritable bowel syndrome (IBS). He shares insights from novel research happening in the Pimentel Lab, where he serves as the executive director of the esteemed Medically Associated Science and Technology (MAST) Program at Cedars-Sinai in Los Angeles, California.   We kick off this episode debunking the myth that IBS is a woman's only disorder highlighting the importance of funding research for GI conditions which is essential for ALL.
 
Ever experience food poisoning? Learn how this may or may not have contributed to your current GI symptoms. We delve into the complexities of diagnosing SIBO with breath testing and examine its evolving credibility.  We discuss how current state-of-the-art research is steering us toward more precise, microbiome-friendly treatments.
 
We conclude with a holistic perspective on managing gut health, with a scientific review of the impact of artificial sweeteners to the up-and-coming tailored approaches needed for conditions like SIBO.  We address the critical importance of personalized treatment in the face of medical gatekeeping and underscore the necessity of balance in both diet and lifestyle. 

Tune in for an insightful episode that promises to enrich your understanding of the delicate interplay with small intestinal microbes and our digestive system.
And... join our Gut Health Podcast Community! Subscribe and share – your gut will thank you!

This episode is sponsored by Ardelyx.
Reference:
Leite G, Morales W, Weitsman S, et al. The duodenal microbiome is altered in small intestinal bacterial overgrowth. PLoS One. 2020;15(7):e0234906. Published 2020 Jul 9. doi:10.1371/journal.pone.0234906

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 Scarlata:

This podcast has been sponsored by Ardelyx. 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 about all things related to your gut and well-being. We are your hosts. I'm Kate Scarlata, a GI dietitian.

Megan Riehl:

And I am Dr Megan Riehl. We have a very exciting podcast for you today. We are going to be talking about small intestinal bacterial overgrowth, also known as SIBO, and we will be discussing the small intestine microbiome. And maybe you've suffered with SIBO, maybe you've never heard of it, but either way, I'd say we are going to be getting a little heavy into the science today and I think you're going to be fascinated.

Kate Scarlata:

Our guest today is a maverick. He's really pushed the science and understanding SIBO for all of us. He is a world-renowned gastroenterologist and researcher, Dr Mark Pimentel. Dr Pimentel is the executive director of the Medically Associated Science and Technology, otherwise known as MAST program at Cedars-Sinai in Los Angeles, California. Pimentel's team researches IBS irritable bowel syndrome one of the most prevalent GI conditions, impacting about 11% of the population worldwide, as well as the condition of small intestinal bacterial overgrowth and intestinal methanogen overgrowth. Wow, I know that's a mouthful, but these two conditions are often associated with significant GI symptoms. Welcome to the Gut Health Podcast, Dr Pimentel.

Mark Pimentel:

It's so good to be with you both and I'm excited to talk about my favorite subjects.

Megan Riehl:

Awesome. Yeah, we're very excited to learn from you and to share you with our listeners. So, as we dive in into the world of gut health, we like to bust myths and address misinformation, because right now, there's a lot of stuff out there that is not based in science or coming from reputable sources like yourself. We call it the snake oil. So when it comes to SIBO, we have literally one of the most credible sources in the field of gastroenterology. Dr Pimentel, what is a common misconception about gut health or GI disorders that you'd like to dispel for our audience today?

Mark Pimentel:

There's a lot of myths. The biggest myth that I have spent my maverick years busting is that IBS is a women's disease quote unquote which is ridiculous. First of all, you do not blame a gender for a disease. That's one aspect of it, and that it's something to do with hormones or something to do with women in general, or their anxiety or their hysteria, as they used to call it. And that mythbusting that was the principal priority of my work for many years is to say look, it's a real thing and men have it. And it's not to validate men that have it. It's to validate that it isn't a gender-specific condition, albeit there are more women with it, but the condition was dismissed and, as in a lot of female predominant conditions, there's less funding as well, which is also sad. So biggest myth is stop blaming women for the disease and start figuring it out, and I think we've come a long way. At least our lab has.

Megan Riehl:

Your lab has, and it really is again trailblazing, because you're absolutely right, funding inequities and looking at the variety of different strategies that we can use to address these types of diagnoses is only going to change if our mindset around diagnosis changes. So thank you for leading the way. We have some questions for you now, and we're going to start with one. What is small intestinal bacterial overgrowth? What is the overlap with IBS?

Mark Pimentel:

The definition is changing because of science, not because of opinion, unlike Rome criteria, which is more from opinion than science. Sorry, that was my little plug for my pet peeve. So what we realized in the beginning, or what we thought in the beginning, was that SIBO was all these colon bacteria moving into the small intestine, because maybe the motility was bad, maybe there's a partial blockage or something else. But it's not that. It's not that at all. It's much more interesting than that because in the latest study which just came out this month, we show that SIBO, or small intestinal bacterial overgrowth, is an accumulation of two or three strains of bacteria. That's it.

Mark Pimentel:

Imagine that you look in a part of your body let's say an infection in your skin you find predominantly Staph aureus. Well, it's a Staph aureus skin infection. What we found in SIBO patients who had greater than 10 to the 3 growing based on aspirates we found E coli K12, almost responsible for 50% of all the organisms in the small bowel just one strain of one species. So it's really eye-opening even for us to see that specificity. And so we can't call it an infection, but it sounds like an infection because it's only one character and then maybe a little bit of Klebsiella pneumonia thrown in there, which is another species. So it's really two characters that are dominating the whole SIBO field.

Megan Riehl:

And what's the overlap with IBS?

Mark Pimentel:

The overlap with IBS is based on a lot of different meta-analyses. The most recent one is from Ayesha Shah from Australia, where they show that there's absolutely more SIBO in IBS than there is in healthy. If you look at breath tests, if you look at culture studies, it's the same thing and the overlap appears to be based on one study where they studied IBS and compared it to non-healthy individuals. The overlap is 60%. So if you go back and look at H pylori, H pylori causing ulcers was about 60% to 80%, and now when you do culture of the small bowel of an IBS-D patient, you're seeing 60%. So it isn't too dissimilar to the H pylori story from the 80s and 70s.

Megan Riehl:

Yeah, it's fascinating. What are some of the key symptoms with this condition? What are patients presenting with?

Mark Pimentel:

You know, what we see is bloating, of course, because the bacteria produce gas. And one of the things that we noted in this recent study we published in January was that when you have this SIBO, when you have these very unique characters in the small bowel, these patients are almost 63 times more fermenting than people who are normal. Can you imagine that? That your normal person's a one horsepower engine for making gas and you're a 63 horsepower engine? And then you wonder why patients say well, I have 10 minutes after I eat, I'm getting bloating and gas and then pain because you get pain.

Mark Pimentel:

But what we've shown in a basic science study so the two papers in fact these two papers are probably the most pivotal papers we've ever written, also published in January shows that food poisoning starts the whole process and we figured out which toxin it was. It's the CDTV toxin, was it's the CDTV toxin? And when we gave the CDTV toxin to rats in their back, not in their gut, they developed SIBO, they developed upregulation of pathways, of visceral hypersensitivity in their gut. They developed changes in their permeability, they developed gut motility, serotonin pathway changes to suggest changes in motility as well. So it's food poisoning. The CDTV toxin leads to all these abnormal functions. That leads to the bacterial overgrowth and they further augment the hypersensitivity, because these bacteria produce toxins and things that you don't want and you get an inflammatory response, albeit mild, not mild enough not to cause symptoms. Mild enough to cause symptoms.

Megan Riehl:

Right, and people are living with this, confused because it sounds like they may be picking up a food poisoning that either they were aware of or they had no idea, and kind of just were living life, moving forward knowing something had changed.

Mark Pimentel:

Exactly. I mean, if you ask 100 people in their 20s if they ever had food poisoning, you're going to get 100 yeses. So it's a little tricky because not everybody who gets food poisoning gets IBS and the Mayo Clinic showed that in their meta-analysis that about 11% of you know. If you go to a wedding and 100 people get sick, only 11 out of 100 are going to progress to IBS because of their immune system or whatever their reactivity is to this insult. But yes, food poisoning. They may not even remember the food poisoning and they have been on a trip and they had, you know, a couple hours of diarrhea and didn't even think about it and then two months later they're suffering with IBS for the rest of their life. So it's fascinating.

Megan Riehl:

Two months later, they're suffering with IBS for the rest of their life. So it's fascinating, yeah, I think. When people are presenting finally to a doctor with symptoms, breath testing tends to be one thing that may be suggested, but it seems kind of controversial. So why is that? What's the breath testing scenario?

Mark Pimentel:

So the breath testing has gone through stages of development. Let's put it that way Stages of gone through stages of development. Let's put it that way Stages of understanding and stages of development. I don't want to make this into a long diatribe, but the original gas was hydrogen, and hydrogen while if it's abnormal you have symptoms, but it's not proportional. So if your hydrogen is 30, which is abnormal at 90 minutes, you have overgrowth, but if it's 100, you don't have more symptoms than somebody with 30. And nobody can understand that. And they say well, if it's SIBO, then why is this? Why is that? And then you have to do culture and you have to prove that the breath test correlates with culture and all that. And that couldn't be done back in the 1980s when this was going on.

Mark Pimentel:

So then they added methane. Why did they add methane? Nobody knows. And there was no science to say methane had any importance. And I know we're going to get to methane.

Mark Pimentel:

And then we later learned it causes constipation. But there was a third gas, hydrogen sulfide, which we couldn't measure. So methane, the more it is, the more constipated you are. Hydrogen was not a thermometer, but hydrogen sulfide is a thermometer. The more you have, the more diarrhea you have. So it was a missing part of the breath test to allow the science to sort of come to its fruition. And I'll say one final thing In fact, the first validation of breath testing, the true validation, was in 2022, in December.

Mark Pimentel:

So we've been doing breath testing for 40 years and in 2022, we did the study where we took diarrhea, ibs patients, constipation, ibs patients, breath testing with three gases and the microbiome. We showed that what you see on the breath correlates with the microbiome and correlates with the symptoms. And it's the first time that triangle was completed in a full, single study. And so you could say breath test was finally validated to be accurate in 2022, which is a sad testament, but we sort of knew it was correct. But you had to get the hard, hard data and that's what we finally did.

Megan Riehl:

Okay. So there is a lot of SIBO snake oil out there. You Google it, lots of different concoctions of supplements and cleanses and diets and all of that is out there. As a psychologist, this can be so anxiety-provoking for patients, and weeding through it all and finding out what's the short-term and the long-term of the treatment can be difficult without again talking with a reputable source. So what advice do you give to patients and how do you counsel your patients with treatment?

Mark Pimentel:

Well, even before SIBO, the industry, or the cottage industry, of natural products has always looked for a niche or a wedge in order to sell a product and to provide some healthcare benefit based on limited data. So you can always find one study that says one thing does, maybe reduces one cytokine, and then you say, oh, let's sell that, but what does it do on a holistic basis to that person, not just the single cytokine, and you're sort of putting that as your anchor. And a lot of these products don't go through randomized control trials. I'm going to go a little bit extreme peppermint. Okay, they did one small study and it was significant, using modest framed endpoints, not the FDA endpoint. You want to prove if something works compared to a drug that's FDA approved. I want to see a thousand patients, I want to see the FDA endpoints, which are very difficult, and then I believe it. Then it's toe-to-toe with what's drug approved. But they can't spend that kind of money.

Mark Pimentel:

In fact, what we saw in peppermint, for example, is we did a meta analysis looking at the size of the study, and you both know this the bigger the study, the better the p-value right, because you're getting more N. What we saw with peppermint is the bigger the study, the worse the p-value got. That's the wrong direction. That means that it's suffering from small study bias and you get a positive small study and you make a big big thing of it. I'm not picking on peppermint, but probiotics is the same thing. Lactobacillus, lactobacillus, lactobacillus. For 30, 40 years now we think lactobacillus is a disruptor of the small bowel, because nobody looked in the small bowel. They always looked in the colon and stool, and lactobacillus is terrible for the small bowel and you're going to see something very, very interesting come out in a paper that's already in review and I can't tell you what it is, but it's going to cause people to curl their hair a little bit and it's lactobacillus being very, very bad, and we can talk more about that another time.

Megan Riehl:

You have me on the edge of my seat.

Kate Scarlata:

Before I get sort of into my questions with you, I did want you to talk a little bit about the difference between small intestinal bacterial overgrowth and intestinal methanogen overgrowth, because I know these differ and a lot of people haven't heard about intestinal methanogen overgrowth. Because I know these differ and a lot of people haven't heard about intestinal methanogen overgrowth, so let's get into it.

Mark Pimentel:

I'm happy to. So, in contrast to what we've discussed with IBS-D and the relationship to SIBO, which is the E coli, klebsiella and then the hydrogen sulfide production which I just barely touched on. That's all caused, we think, from food poisoning. So that's the trajectory. That's not the case for methane. We don't know exactly why methane accumulates more in some individuals versus another, except to say that it clusters in families, maybe sharing the environment.

Mark Pimentel:

You share your microbes, toilets, etc. You know the usual way you share your microbiome, which is a little PG-13. But it just happens you're in the same environment and you share your microbiome and so you accumulate methane. And the more methane you accumulate beyond what is a normal level, then you develop constipation and that's intestinal methanogen overgrowth. So it used to be lumped in SIBO. But we realized that the methanogens are elevated in stool and the small intestine. And we do have a large abstract that we're presenting at DDW which describes everywhere methanogens grow, their proportions and who they are.

Mark Pimentel:

But it all boils down mostly to one single organism methanobrevibacter smithii. So I want to pause there because you know, in all the 15 to 20 years of microbiome research, do you both know of a single name, of a single organism causing a disease in all this 20 years of microbiome research, because I don't, I don't know a c diff, but that predates all of that. But I've told you on this call that E, coli, k12 and Klebsiella pneumoniae are causing SIBO. I'm telling you that we've discovered that Methanobrevibacter smithii is causing constipation and that Fusobacterium and Decephalovibrio are causing the diarrhea of hydrogen sulfide. So our group has nailed down single organisms to single disease in a number of areas, which is really exciting for the patients and your listeners, because this gives us now the nail for our hammer. You can't just treat SIBO coliforms, you have to treat the nail and now that it's become so clear it's a specific nail, we can figure out treatments for the specific nail and we are and we are already way into that, which is really exciting.

Megan Riehl:

You know, the reality is, even if I did know it, I wouldn't be able to pronounce it. So thank goodness that you're able to do that for us, because even if I knew it, I wouldn't.

Mark Pimentel:

I didn't want to put you on the spot and wait for an answer because there's so many wacky names.

Megan Riehl:

Well, thank you.

Mark Pimentel:

There hasn't been anything that's caught the media's attention as a smoking gun, and now we have three smoking guns. So it's pretty exciting times for IBS-D, IBS-C, functional disorders or DGBIs, because we're starting to sort out some of these relationships between the gut microbiome and how they're going to. Some of them produce serotonin, they affect the brain and sort of unlocking the secrets of how there's this mystery of how everything worked. The Pandora's box is opening.

Kate Scarlata:

It's really remarkable because I was diagnosed with SIBO in 2003. And it was like no one was talking about it. I mean, I had to educate my gastroenterologist to treat me and just to see how this I mean really your lab doing all of this nitty gritty work into the microbiome to you know, as you say, find that nail so that we can have targeted treatments, instead of giving these full spectrumspectrum antibiotics, because we know the gut microbiome and the microbes there for the most part are really important and we're really not treating. You don't want to disseminate these organisms, do we with targeted treatments, or do we want to just reduce them? Like, what is the goal here with treatment, when you're thinking about treatments ahead?

Mark Pimentel:

Well, the program I run here is now determined and far along that path, which I can't tell you where we are exactly, but we already have molecules, let's put it that way that are the hammers. But our goal is to develop a drug for a bug, not a drug for you a drug for that specific bug, and leave everything else alone as much as possible. And so our mission now is to be very specific to the bug, but it's not necessarily to kill it. Not an antibiotic, just reduce it and get it back to the normal level, because we really don't want to wreck everything and we don't want to use a wrecking ball to treat the patient. We want to use boutique therapies, and I think we've got some and we just have to march it along and get the right data and make sure it's done properly.

Kate Scarlata:

Important. So you've talked a little bit about the microbes that are there, a lot a bit about the microbes that are there and their impact on symptoms. Are there certain microbes like just to drill it down a little bit more for our listeners that create certain symptoms or symptom severity?

Mark Pimentel:

I know methane is constipation but beyond, like some of the other small microbiome- In terms of what we've been discussing methane the higher it gets, the more constipated a person is, and I have patients where you know normally methane will be elevated, about 40 or 50, who are 200 for methane and they're absolutely miserable people because they're so bloated. They talk about IBS-D being a low quality of life. I can tell you it's much lower. On the constipation side, If you never have a bowel movement properly, you never feel relief. At least with the diarrhea patients, when they have the purge they feel some relief for a period of time, but the methane people never feel relief and methane is more stubborn and requires a better treatment.

Mark Pimentel:

The new kid on the block, the hydrogen sulfide as part of the three gas breath test that's amazing what we're learning and we're continuing to learn, and you'll see at DDW some more data and another couple of papers that are coming out in the next four or five months. It's a direct line between hydrogen sulfide and diarrhea. It's a direct line. So the lower we can get that, the better. The diarrhea IBS patients or the diarrhea SIBO patients, if you want to call them that, are going to be. So it's pretty incredible now that we've unlocked these things. We didn't have three gases before, so we couldn't see this. I don't fault people for criticizing breath testing. I mean my task all these years. In saying that breath testing was important is because it looked important. We were seeing the signals, but we were missing pieces, and that was the frustration among the scientists and among myself. So we had to answer the question, we had to move to the next level, and now we're there, so we're starting to see the right signals.

Kate Scarlata:

It's amazing. This is a little off grid from the questions that I provided to you, dr Pimentel, but you know, with the hydrogen sulfide gas and sulfur in your diet, do you anticipate there'll be a nutritional intervention with that particular condition, the hydrogen sulfide positive SIBO?

Mark Pimentel:

with that particular condition, the hydrogen sulfide positive SIBO. Well, wouldn't it make your life more interesting if I mean as a clinician treating patients you know somebody who sees patients like yourselves is to. You'd have a diet for the hydrogen sulfide low sulfur diet, a diet for the methane maybe low acid, low hydrogen sources, and then a diet for SIBO maybe it's low FODMAP or low fermentation, and so it isn't, you know, one big sledgehammer. It's actually more sophisticated than that and maybe better. Those have not been developed, but it's not. I mean, I can think about it already, what it might look like, the construct might look like, and I think that will help patients in the long run better than just one size fits all kind of treatment.

Kate Scarlata:

Absolutely so. Your group did an artificial sweetener study looking at its impact on the small intestinal microbiome. Can you share what you learned?

Mark Pimentel:

I can share it in sort of broad swaths. But what we see is that artificial sweetener ingestion does change the microbiome markedly, especially the sugars not aspartame I'll speak about aspartame in a minute. But the artificial sugars, the sorbitol, the alcohol sugars, sucralose and all of those had a dramatic impact, as we would have expected. That because they're not absorbed they're sugars the bacteria can metabolize them and so you're selecting bacteria that are not typically seen in higher abundance because they like to digest that sugar. The question is how does that affect health? And our sample size wasn't large enough to say, okay, well, we have a thousand people on sucralose and they have a detrimental health effect. But now going to aspartame, it didn't have that effect. You didn't have a big change in the microbiome.

Mark Pimentel:

But you know there was a study that said there might be liver toxicity from aspartame. That came out recently. We found that there was a higher abundance of a liver toxin that we saw in the metabolome. We didn't see much changes in the microbiome, but in the metabolome we saw more of this liver toxin. So that needs further exploration. So maybe that's why there is some toxicity. So as much as I liked aspartame as a good sweetener, I have to shake my head a little bit and say, okay, am I doing the right thing or not? Now we have this data, we have to rethink things. What are we going to sweeten stuff with? And so we all learn. We have to learn and we have to adapt.

Kate Scarlata:

Well, I'm a big maple syrup sweetener queen over here. I think a little sugar is okay, a little sucrose. IBS-C, or irritable bowel syndrome with constipation, is a common condition in which people experience constipation along with other belly symptoms like pain, bloating and discomfort Sound familiar. Many people with IBS-C are willing to give up key parts of their lives in exchange for symptom relief. And because the causes of IBS-C may differ for each person, there is no one-size-fits-all treatment approach.

Kate Scarlata:

If you're suffering from IBS-C, you may have to try a number of different medications before you find the right one for you. So don't be okay with just feeling okay. If you have IBS symptoms that continue to bother you, talk to your healthcare provider to find out if your current medication is right for you or if it's time to try something different. The more you know about IBS-C, the better prepared you will be to speak with your doctor about the right treatment option for you. So I wanted to talk a little bit about medical gatekeeping or just physicians in general that just don't believe in SIBO, and how that might impact our patients. Out there there's definitely a camp that just does not want to see SIBO as a real diagnosis and unfortunately I've seen some of those patients come to my office and really feel lost, and I imagine you get a lot of these patients winding up at your office. So can you talk just about that impact on these patients out there that are looking for care?

Mark Pimentel:

And there's various steps of physicians. There are still physicians who will see an IBS patient and say look, you're not going to die, get over it, you're fine, you've had it for 10 years. Go do some yoga, relax. There are still physicians who do this or various combinations and permutations of not taking the patient seriously and saying get on with your life, which I think is undereducated by an extreme amount. The next step are the skeptics of breath testing, because I don't blame them for being skeptical.

Mark Pimentel:

Until 2022, which I just described to you we didn't have the best validation of breath testing. We had a lot of data and a lot of signal and strong studies that suggest it was important. But if you're going to be a skeptic in the minority, you could say we didn't have the sequencing versus symptoms, versus breath test validation, and we didn't have the three gases. We didn't have all that. Well, we have all of that now, and so now it's a matter of educating those I hope, minority groups of physicians who are still stubbornly thinking this is a fad rather than a fact.

Mark Pimentel:

But you know, sometimes with breath testing and SIBO and you see it because you see it on social media there is a tendency to embellish it in a fad fashion Everything is SIBO, everything is SIBO, everything is SIBO. I can tell you, in my office when I see a SIBO patient, nothing is SIBO till I'm sure. And I've undone that diagnosis in a number of patients where I found some other explanation. When they come to my office I say I'm assuming you don't have SIBO and I'm going to see what? Because nothing, they haven't responded, they haven't done, they haven't responded in the typical way, and so I sort of undo that diagnosis in some instances. So there's the doctors who are stubborn and maybe that's undereducated. And then there are doctors who overcall SIBO, because they are undereducated as well, because they just want to call everything a nail, and so we get both ends of that.

Kate Scarlata:

Yeah, I absolutely see that too. You know it worries me when patients are just chronically treated with antibiotics and really not getting to maybe something else going on. We definitely see that.

Mark Pimentel:

I had a patient as an example where she was treated with rifaximin, for example, for four or five times, no benefit. We finally were able to do the three gas breath test. She had hydrogen sulfide. We gave her rifaximin and bismuth. The hydrogen sulfide went away, her diarrhea, which was like eight times a day, totally gone and it hasn't come back. It's been a year and a half. But that's an example of a SIBO undereducated, under-evaluated, because this is all new data. And then there are other examples where it turns out to be cancer or it turns out to be be something else and the doctor is barking up the wrong tree because it's the simplest explanation you know.

Kate Scarlata:

No, I love it. I always tell people if plan A isn't working, same for a low FODMAP diet or you know, whatever treatment modality they're doing like we need to come up with plan B, C and D. There's so many options and why are we doing the same thing that's not working?

Megan Riehl:

And oftentimes it's anxiety, it's the fear that, well, maybe it is working. You know, maybe I did get 10% relief from that antibiotic, so I want to do it again because I think I may be and it really takes the confidence of the physician to, you know, say let's look at other things, let's involve maybe some other team members and we have other stones that we can overturn here.

Mark Pimentel:

But that's again education, and when a physician or a health professional is educated properly, they can take command of the situation. They don't have that confidence as you described, Megan. They can't confidently make the patient feel confident that they know what they're doing and therefore they start exploring the internet on their own to come up with answers. And so confidence comes. Grow that education and that some of our listeners may change some of their practices in medicine, based on your expertise and us having the opportunity to talk.

Kate Scarlata:

I know I agree with that. I agree with that. I just want to back up a little bit because you did mention the bismuth with the rifaximin. Do you want to just talk a little bit about what you have found in your practice to be working for some of these hydrogen sulfide cases?

Mark Pimentel:

Yeah, so for hydrogen sulfide, we have a randomized controlled trial which we haven't publicized yet. It hasn't come out for some new products that we're working on, but as it stands now and remember I talked about and said things about peppermint and other products we need controlled trials. So what I'm going to tell you today is not a controlled study. It's based on historical data that suggests that bismuth really reduces hydrogen sulfide in the gut, and so we have adopted that based on studies from the 90s, adding it to rifaximin because you got to get rid of the hydrogen. We know it works there for rifaximin and bismuth, reducing the hydrogen sulfide, then getting both of those together because you need hydrogen to make hydrogen sulfide, so that your audience understands that it seems to work very well in our practice. But this is not based on a randomized control trial yet, but you'll see data coming, hopefully this year.

Kate Scarlata:

Awesome. So let me review a few key points from today's episode, and I'm definitely going to have Dr Pimentel weigh in, make sure I got most of them. So we understand that SIBO presents very similarly to IBS, often if it's diarrhea-predominant, like IBS-D we often see that SIBO diagnosis related to hydrogen sulfide gas Intestinal methanogen overgrowth appears to be associated with constipation. So you might see that in your patients or with yourself if you experience IBS with a constipation predominance predominance.

Kate Scarlata:

We're beginning to understand a little bit about the small intestinal microbiome and who's there and what is really impacting SIBO. One of the things you said and I'm going to interject with you now, Mark is the metabolome and I think you know when we talk about the gut microbiome initially, when the science came to sort of the front in the early 2000s or so, we were all talking about what microbes are there and now we're really shifting a little bit into this metabolome and what they're making and what they're doing. So you mentioned is it aspartame? It was really the metabolome. Can you just talk a little bit about the metabolome and how you look at that in the research setting?

Mark Pimentel:

Well, I gave you sort of an example without using the term metabolome, but we're able to see in the metabolome of SIBO, which is the topic of today, the immense upregulation of the metabolic function to break down carbohydrates, and I use the term 63-fold or 63-horsepower engine.

Mark Pimentel:

And so by studying the metabolome we see that. Wow, now that explains to me why my patients say 10 minutes after I eat. But there's a thing called the interactome, which is the metabolome, the composition of your microbiome, their products and the host response to all of that milieu. And so we've actually dug into that as well. Which is what we brushed across earlier. Is that we actually see in the tissue that the chemistry for gut hypersensitivity is there, the chemistry for cell-cell interaction, to allow that quote, leakiness to the gut. We see the serotonin signaling pathways altered, which we know affects motility in a particular way. So there's an interaction that's occurring from a consequence of the microbiome changing the chemistry that they produce and that chemistry affecting you in that way, and so we're able to really again triangulating on cause and effect pathways.

Kate Scarlata:

It's really amazing and I just you see these stool tests just looking at you know, really targeted to people with IBS, with just the stool microbes and it's just like such a small window into the microbiome and seemingly useless when you see the complexity of this interaction that you just described.

Mark Pimentel:

Well, and one other point, which is another misunderstanding of the microbiome. When you think about the microbiome of stool, the density of microbes in stool is way higher than the small bowel. But it's in a cylinder, right for the most part, and you only see the outside of the cylinder. The inside is just the microbes doing their thing. You don't see the metabolic stuff on the inside as much, it's only what gets to the outside. So the surface area exposure of the microbiome and the colon is quite small, even though the contents are larger.

Mark Pimentel:

The small bowel is the size of a tennis court, although I was corrected on the social media recently but it's a large surface area where, if you were to, you know, put a thin layer of bacterial pita butter on that surface which absorbs everything or is meant to absorb things, the impact on the human is immense. I mean, it's much more than the colon. And so we know now that the colon microbiome is like a different planet, it's like Mars compared to the earth, which is the small bowel. And so understanding the small bowel is so vitally important, because that's where things get absorbed.

Kate Scarlata:

So important I want to just talk as sort of. One of our main points is just that SIBO can be anxiety producing. You know it's a tough diagnosis. Having lived it myself and what a difference after being treated. You know like I could live my life again. Team, you know I think patients are very confused about what they should be eating and you know I almost called it like PTSD. I'm no psychologist, megan, but when I had SIBO I was just like the wary of it coming back because I was so sick. I went into this like any gas bubble. I felt like I'd be like oh, please don't be this again. So getting a GI psychologist involved too, if that just really escalates a little bit in the wrong direction, I think that team approach can be really helpful for our patients. Yeah, you're describing hypervigilance.

Megan Riehl:

You're describing GI-specific anxiety where a gurgle sends signals up to the brain to interpret what the heck is going on down there and, as we've learned with this diagnosis, it can be like trying to find a needle in a haystack. So as soon as we kind of step back and you are seated with a practitioner, you know we're going to utilize different brain, gut, behavioral therapies in conjunction with working with, potentially, a dietician, a gastroenterologist, a primary care doctor, to really address your whole health and how this has impacted how you eat, how you behave, which all impacts our gut microbiome. But you're absolutely right, you may feel symptoms of hypervigilance and hypersensitivity because of a diagnosis like this, and we can address that?

Kate Scarlata:

Yeah, that's excellent. I think too, you know we see these food-related symptoms in patients with bacterial overgrowth, as Dr Pimentel mentioned. Like 10 minutes after eating. Well, you know, the food's getting into that small bowel pretty quickly and if there's a lot of different players in there that have, to your point, upregulated ability to degrade carbohydrates and ferment vast amounts of gas in that small intestine, which is really not designed to accommodate all of that gas, how uncomfortable that would lead you. But on the flip side of that, getting rid of those microbes and reducing them, those food-related symptoms can go away, and so long-term diet strategies may help prevent the recurrent return of SIBO. We don't really know that, but there is hope that one doesn't need to be really on this long strict diet forever, and I think people do get into that a little bit. Can you comment to that, dr Pimentel, about just the necessity for everyone should be on a strict diet long-term?

Mark Pimentel:

Well, for example, in SIBO, as we've been discussing, there are patients where you treat once and you don't see them for years. They're so mild, symptomatic enough to see the physician, but the pathophysiology isn't that dense that they relapse. The motility isn't as affected by the food poisoning. And now going backwards in time to what we talked about earlier. But there are patients where a diet which is a fairly quote-unquote, benign way of keeping the patient from relapsing meaning it's not a drug. But you do get into this hypervigilance, as you both have described.

Mark Pimentel:

I had a patient where she would have incontinence from her diarrhea. She was an older woman. We treated her SIBO. She still wouldn't go to the grocery store, even though everything was normal. But after some coaching and time she was flying, she was showing her dogs at dog shows, she was doing all the things that she loved. So it was amazing.

Mark Pimentel:

But it takes time to break the hypervigilance. But the same thing happens with food. You get a fear of food and a fear of things that made you unwell before. But I'll say one other thing which really gets in the weeds for patients. People think I've got bloating. Therefore, what I ate an hour ago is to blame, and in a microbiology world.

Mark Pimentel:

That is not true. The way it works is you ate beans three days ago, the beans increase the amount of bacteria in your gut, so that today the amount of bacteria in your gut, so that today the amount of bacteria in your gut is way higher than it was three days ago. And you had pasta at the same restaurant, which didn't bother you last week, but today it did scratch that pasta off my list. I can never eat it again. And then you keep scratching things off the list, not understanding how the microbiome works, and you scratch until you're left with chicken and rice and hence ARFID or these disorders of eating as a result of IBS and SIBO. If you don't have a health practitioner who can explain those things to the patient, they end up restricting and restricting and restricting. It's not the pasta, it's the meal you ate two days ago that made this meal bad. That's just an example. And so having a health practitioner who understands diet and can counsel the patient so having a team I agree with you both having a team is important.

Kate Scarlata:

Yeah, and I would just add you know bloating can occur when there's a lot of psychological angst, when someone is full of stool.

Kate Scarlata:

You know there are other reasons and I think to your comment that diet is a benign intervention, I agree it is not a benign intervention because of just what you described and that people can go down this rabbit hole of restricting and restricting, and we know that some of these very highly restrictive eating disorders place individuals at increased mortality. So we want to be careful with that semantics, so to speak. I mean, I know where you are going with, but diet has some issues with it. It can be very helpful I see it helping patients all the time but on that flip side, when you take it to that next level, it can be really problematic. And I would say you know when I say this to my patients, it's like you need fuel for your gut motility to work and for your pelvic floor to work appropriately, so that efforts to restrict the diet to help the SIBO are actually impacting gut motility and function and they're missing this very vital point that is essential for maintaining a healthy gut. Would you agree to that or you feel free to disagree with me?

Mark Pimentel:

No, I mean, the extreme example of what you're saying is anorexia. Right, you have bloating because, in part because the muscles of the gut no longer have any strength, so the distension is more prominent, and then the body dysmorphism can be more prominent, and then you want to restrict calories more to see if you can get rid of that. So that's just part of anorexia. Anorexia is a much more complicated issue than I'm simplifying. The point is protein will build the muscle and the muscle builds. Then the gut works better. It's a balance and I think patients get too restricted.

Mark Pimentel:

But diet plays a very important role in all of these treatments. But my main point was you have to have a health professional that understands how to do it correctly, to guide the patient, rather than simply just anybody telling you to do X, Y or Z indiscriminately. And you've seen this where somebody goes on a low FODMAP diet and they've been on it for a year and a half because nobody told them they should do anything different, and now they have some nutritional deficiencies, and so you can't just throw something at somebody and then never see them back and follow up and guide them further.

Kate Scarlata:

Absolutely. I could not agree more. You know, I see a lot of online sites recommending an placebo protocol with a slurry of supplements and their special diet, and we know that this condition really isn't one size fits all right.

Mark Pimentel:

You mean, like with supplements, all mixed together?

Kate Scarlata:

Yeah, if you just put SIBO protocol online, you will be horrified with people out there with maybe had SIBO themselves or have no medical credentials, and a lot of people gravitate to this and they're really, you know, a probiotic, a biofilm disruptor, specific diets, you know, not discounting. I'm just not sure some of this is science-based at this time.

Mark Pimentel:

I have to be careful because, as a scientist and as you, from being a maverick in the beginning, I don't discount anything. I say there's no data. Because there are things like, for example, berberine. I wasn't altogether a fan of berberine, I wasn't sure. And then Johns Hopkins did a study that said that a combination of berberine. I wasn't sure, and then Johns Hopkins did a study that said that a combination of berberine and a couple of other herbal products was as good as rifaximin. So it's not good until you prove it and it's not bad until you prove it. So I think the problem is the claims without data. That's the problem. So it's very important that you get data and if you want to make money on it, you'll make more money if you have data. It's just evidence-based.

Kate Scarlata:

Finally, yeah, well, we're getting there and I agree with you. I totally agree with that. There's a lot of information out there that may prove to be the best treatment ever for SIBO, but even with low FODMAP there's no evidence that the low FODMAP diet helps SIBO. We find that it helps manage symptoms in patients clinically, but I can't and will not ever tell a patient that this is the one-all, be-all diet protocol for SIBO. It's just symptoms overlap with IBS. That's what we have, and it may help to reduce FODMAPs, you know? Okay, Megan.

Megan Riehl:

So, outside of lighting up Cedars-Sinai and LA with this microbiome gut health disrupting work that you're doing you've cited so many papers that I can't wait to sink into and share the wealth of information that comes with that. You've got to have time for self-care, I hope as well, and so we like to ask all of our esteemed guests what's something that you do for your own health and well-being, that's, you know, sustainable over the long term.

Mark Pimentel:

Well, you have to be a role model for your patients in a lot of ways, and I think eating healthy I mean these aren't hobbies. Eating healthy, exercising frequently, which I do are not hobbies but just lifestyle choices that I make. But I play blues guitar. Maybe it's something nobody knows, or I try to. Let's call it that it's a midlife crisis. I didn't get a Ferrari, I got a guitar and I counsel everybody who's out there get the Ferrari instead of the guitar. It's less worth it because it's been a 10-year-plus journey of trying to learn the guitar and it never ends what you can learn and it never ends that you feel confident in what you're doing. But that's okay. That's my life journey.

Megan Riehl:

It's lighting up a totally different side of your brain. So I love that for you and I think that it is inspiring to kind of take something that you're clearly very good at what you do in your profession. So a little challenge by the guitar is probably a good thing for you.

Mark Pimentel:

Yes, sometimes it overwhelms the brain because I use the right side of my brain as a fatigue reliever and when I fatigue both sides, I'm pretty tired when I go to bed.

Megan Riehl:

Yeah, you'll sleep better. You'll sleep better, exactly.

Kate Scarlata:

It's all positive, it's all positive.

Mark Pimentel:

It's all positive yeah.

Megan Riehl:

So we have worked with so many patients who have been diagnosed with SIBO. Typically, they're prescribed the antibiotic and hope for the best and onward they go. And this is why this diagnosis really highlights the importance of remembering that everybody's gut microbiome is different. We have to tailor their treatment plan, individualizing it for them, and it certainly gives a shout out to the dream team approach of dietician and, you know, it certainly gives a shout out to the dream team approach of dietitian, psychologist and physician or medical provider. So we just want to say thank you for the work that you're doing, also for all the listeners out there. We do touch on SIBO in our book Mind Your Gut, so certainly something to check out and consider when you're thinking about holistic ways to approach your gut health. So, Kate, what do we expect in our next ?

Kate Scarlata:

Yes so we are talking all about bloating with Dr Brian Lacy. He is a neurogastroenterologist at the Mayo Clinic in Jacksonville, Florida. He is the past co-editor-in-chief of the American Journal of Gastroenterology. We're definitely in for a treat because he is a fantastic provider and just a kind, gentle soul, and it'll be really interesting to hear his take on bloating. He's one of the, I would say, world experts in this area.

Megan Riehl:

All right, we're lucky, we're excited for what's to come, and you guys all know the drill at this point. So make sure you subscribe, follow and like The Gut Health Podcast. Tell your friends, your patients, your loved ones, all about us. Know that gut health matters for everyone and your support means the world. Our friends have a great day, thanks again Mark.

Mark Pimentel:

Thank you, take care.

Megan Riehl:

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 at T he Gut Health Podcast, where we'd love for you to share your thoughts, questions and experiences. Thanks for tuning in, friends.

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Kate Scarlata

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