Prebiotics and FODMAPs While Treating SIBO- Episode 51

Thought you knew everything there was to know about SIBO? As always, Dr. Ruscio continues to dig into the newest research. One of our most popular guests, Dr. Allison Siebecker, returns this week with another great discussion on SIBO.

If you need help with SIBO or IBS, click here.

Dr. R’s Fast Facts

  • Whether you consume or avoid prebiotics and/or FODMAPs during SIBO treatment does not appear to have a significant impact on SIBO.
  • Published evidence suggests that probiotics may be more effective in treating or enhancing SIBO treatment than prebiotics.
  • Probiotics have been shown to be an effective SIBO treatment and help with SIBO and IBS symptoms:
    • Perhaps because probiotics may exert more impact on the small intestine than the large intestine.
  • Dead or ‘heat-killed’ probiotics have positive impact suggesting that living probiotics may not be necessary.
  • There appears to be a subset of SIBO patients who respond well to carbs, prebiotics and fiber, which Dr. R terms as “carbohydrate and prebiotic responders in SIBO.”
  • There may also be some novel prebiotics that are safer and more effective for SIBO than standard prebiotic:
    • Partially hydrolyzed guar gum and a type of galacto-oligosaccharide (GOS) found in a compound called Bimuno.

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Fast facts…..0:42
Dr. Siebecker intro…..2:52
Dr. Ruscio’s approach to FODMAPs and prebiotics in treatment of SIBO…..4:16
The research on probiotics and prebiotics in treating SIBO…..7:40
Probiotics as antibacterial agents…..16:08
Probiotics and colonization…..19:18
Carbohydrate and prebiotic responders in SIBO…..22:13
The importance of fact checking…..33:14
Dietary recommendations for SIBO…..37:14
Episode wrap-up…..49:36


  1. (7:40) Rifaximin w PRObiotics better than Rifaximin with PREbiotics Trusted SourcePubMedGo to source
  2. (4:16)
  3. (8:33) Probiotics after Rifaximin enhanced success rate from 50% to 82% Trusted SourcePubMedGo to source
  4. (8:40) Prebiotics enhance treatment success in SIBO Trusted SourcePubMedGo to source
  5. (9:25) Studies using probiotics to treat SIBO have shown:
    1. Trusted SourcePubMedGo to source
    2. Trusted SourcePubMedGo to source
    3. Trusted SourcePubMedGo to source
  6. (10:07) Two meta-analyses have shown probiotics to significantly improve symptoms in IBS and have no side effects:
    1. Trusted SourcePubMedGo to source
    2. Trusted SourcePubMedGo to source
  7. (16:08) Probiotics as antibacterial agents Trusted SourcePubMedGo to source
  8. (19:18) Probiotics and colonization:
    1. Trusted SourcePubMedGo to source
    2. Trusted SourcePubMedGo to source
    3. Trusted SourcePubMedGo to source
  9. (20:03) Heat Killed Probiotics:
    1. A multi-center RCT found that heat-killed lactobacillus was more effective than living lactobacillus in treating diarrhea Trusted SourcePubMedGo to source
    2. Another RCT found heat-killed probiotics improve IBS symptoms Trusted SourcePubMedGo to source
    3. Heat killed lactobacillus was shown to be a successful treatment for skin allergy in adults (aka atopic dermatitis) Trusted SourcePubMedGo to source
    4. Heat killed lactobacillus decreased the incidence of colds in elderly Trusted SourcePubMedGo to source
    5. Heat-killed probiotics enhanced immune function in elderly Trusted SourcePubMedGo to source
    6. Heat-killed probiotics have anti-candida effects in mice Trusted SourcePubMedGo to source
  10. (50:03) SIBO Symposium

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Prebiotics and FODMAPs While Treating SIBO

Welcome to Dr. Ruscio Radio, discussing the cutting edge in health, nutrition, and functional medicine. To make sure you’re up to date on this and other important topics, visit and sign up to receive weekly updates. That’s

The following discussion is for educational purposes only and is not intended to diagnose or treat any disease. Please do not apply any of this information without first speaking with your doctor.

Now, let’s head to the show!

Fast Facts

Dr. Michael Ruscio: Hey, everyone. This is Dr. Ruscio with your fast facts. A great episode with Dr. Allison Siebecker, talking about prebiotics, FODMAPs, and whether you should use those or withhold those during SIBO treatment. Your fast facts: Whether you consume or avoid prebiotics and/or FODMAPs during SIBO treatment does not appear to have a significant impact on SIBO. Published evidence suggests that probiotics may be more effective in treating or enhancing SIBO treatment than prebiotics. Probiotics have been shown to be an effective SIBO treatment and help with SIBO and IBS symptoms perhaps because probiotics may exert more impact on the small intestine than the large intestine, and we elaborate on all of this in the episode. Dead or “heat-killed” probiotics have positive impact, suggesting that living probiotics may not be necessary. There appears to be a subset of SIBO patients who respond well to carbs, prebiotics, and fiber, which I term as “carbohydrate and prebiotic responders in SIBO.” There may also be some novel prebiotics that are safe and more effective for SIBO than standard prebiotics—partially hydrolyzed guar gum and a certain type of GOS found in a compound known as Bimuno.

Well, that’s it, guys. I think you will really, really enjoy this episode. OK, here we go.

DrMR: Hey, folks. Welcome to Dr. Ruscio Radio. I am here with one of my favorite people and a super, super-sharp SIBO clinician, Dr. Allison… is it Siebecker or Siebecker? I always screw it up, and I don’t want to do it again.

Dr. Allison Siebecker: It’s Siebecker.

DrMR: Siebecker, OK. Siebecker, Siebecker, Siebecker. Sorry. I should know that better because I hate it when people screw up my name, which happens all the time. Allison Siebecker is here. Hi! Welcome back!

DrAS: Hi! Thanks for having me back!

DrMR: It’s great to have you back. I’m excited about our call today.

Dr. Siebecker Intro

DrMR: And maybe I should quickly say if people don’t know who Allison is, she is one of the, I think, thought leaders in SIBO, a SIBO specialist very well credentialed in SIBO. You can definitely look her up if you want more on her background, but I think most people probably know her or at least remember her from the last time she was on the show, so we’ll skip over the background credentials and all that stuff and launch right into what I’m very excited to talk about, which is prebiotics and FODMAPs during SIBO treatment.

Recently there’s been a good amount of discussion about, should I eat FODMAPs while I’m being treated for SIBO because the FODMAPs will feed the bacteria, that will make the bacteria eat or uptake more of the antibiotic, and it will increase the success rate? I have some thoughts on that, of course. We’ll probably talk about that for a good 30 or 40 minutes, but that’s kind of the issue that I wanted us to pick apart today.

Allison, I have a few notes here and a few thoughts of my own, so how about I kick us off with what will probably be a decent rant, and then you can either agree, refute, or we can kind of talk through any points of contention from there.

DrAS: Excellent.

Dr. Ruscio’s Approach to FODMAPs and Prebiotics in Treatment of SIBO

DrMR: OK, great. The background, like we already talked about, is maybe eating FODMAPs or taking a prebiotic supplement while being treated for SIBO could increase the effectiveness of the treatment, that treatment being an antibiotic like rifaximin or an herbal antimicrobial. The elemental diet doesn’t really apply because you’re not eating on the elemental diet. So what can we say about this? Well, first I’d like to quickly go through what I do (2) and then go through some of what the research says.

What I typically do is have my patients follow a low-FODMAP diet after the killing phase. When we’re segueing or transitioning off of antibiotics or off of herbal antimicrobials or even back onto food after the elemental diet, that’s when I’ll have someone eat low FODMAP for one to two months and then reintroduce FODMAPs and avoid any FODMAPs that they’ve noticed to be problematic. Now, if they’re already eating low FODMAP, then I advise them to avoid the foods that they notice really kind of provoke them symptomatically, but for the other high-FODMAP foods that they don’t seem to have a problem with, they don’t have to worry about avoiding them.

That’s kind of how I work into this, and my perspective on the question of, does eating FODMAPs or taking prebiotics during treatment have a large impact on the treatment outcome, it’s my opinion that it doesn’t really make a large difference. If someone is going to be a simple SIBO case, they’re probably going to respond really well to any one of the well-established treatments—antibiotics, herbal antimicrobials, elemental diet. If they’re a more complex case, they’re going to require a little bit more of a robust program and plan that’s probably going to have to be custom tailored by a clinician. In other case, I’m open to the prebiotics. I don’t think the plus or minus of them is going to be a make-or-break in the outcome.

There’s also something that we’ll come back to at the end of the episode, which is a concept that Allison and I have been discussing recently, and that’s carbohydrate and prebiotic responders in SIBO, which is something interesting. It’s a clinical observation I’ve made and I’m kind of toying with.

That’s what I do. I’d like to launch into the studies in a minute, but before I do, Allison, any thoughts on that?

DrAS: I just agree with everything you said!

DrMR: Perfect!

DrAS: My approach is very similar to yours, and I think you’re so wise to say that you just don’t think this issue—which everyone is so hot over—is a make-or-break thing.

DrMR: Right, and that’s why I really wanted to get us together as two clinicians that see a lot of SIBO to give people a clinical experience viewpoint on this. Theory is great, but we can really get misguided and spin our wheels if we’re operating based upon supposition and theory. Great, I’m glad that we’re in agreement on that, and I think that we’re in agreement on that because we’re both treating patients on a daily basis and seeing how this kind of fits into the bigger picture.

The Research on Probiotics and Prebiotics in Treating SIBO

DrMR: Some of the studies. We have one study (1 Trusted SourcePubMedGo to source) that kind of answers this question, where rifaximin was given, and then after the rifaximin, a short course of either a probiotic or a prebiotic was administered. Now, the probiotic group saw five out of six symptoms improve, whereas the prebiotic group saw four out of six symptoms improve. So probiotics did a little bit better, and the overall symptomatic reduction, on a scale of 1 to 100, it was about 20 points better, so people did 20 percent better symptomatically with the probiotic than they did with the prebiotic. Both helped, but the probiotic seemed to be a little bit more helpful.

There are some other studies showing that probiotics after rifaximin enhance the success rate (3 Trusted SourcePubMedGo to source), but there are also some studies showing that prebiotics enhance the success rate (4 Trusted SourcePubMedGo to source).

I think there’s mixed data here, but the important point, I think, to bring us back to is don’t get swept up in the craziness about this new concept about eating FODMAPs or taking prebiotics, thinking it’s going to be the next big thing, because we have some studies already done showing that, yes, it is helpful, but probiotics are probably going to be more helpful. I think that’s an important fact for people to be aware of to kind of ground us.

Something else that I think makes the probiotics more attractive—and, Allison, I have to give you credit for making me aware of some of these early studies—there have been studies using probiotics as a stand-alone treatment for SIBO, and I’ll link to a few of them here (5.1 Trusted SourcePubMedGo to source) (5.2 Trusted SourcePubMedGo to source) (5.3 Trusted SourcePubMedGo to source). There have been a handful that have shown that different probiotics administered in different doses have reduced gas levels and eliminated symptoms. We have some data showing that probiotics are a good stand-alone treatment, and I think along those same lines is the fact that we have some very good data looking at probiotics in IBS. If IBS is a constellation of the symptoms that SIBO can manifest as, well, if we have high-level data—and I’ll put in here two meta-analyses that have shown that probiotics are a viable and effective treatment for IBS (6.1 Trusted SourcePubMedGo to source) (6.2 Trusted SourcePubMedGo to source)then I think it very well stands to reason that probiotics are probably going to be a pretty good treatment for SIBO because it reinforces what the previous studies showing that probiotics can treatment SIBO suggest. We have good data for both the symptoms through the IBS studies and for looking at gas levels through the SIBO studies.

Allison, thoughts on that?

DrAS: That’s all really interesting information. It’s a great grounding thing, like you’re saying. One thing that’s a little different on this issue than I think what people are getting excited about with using high-FODMAP foods or prebiotics during treatment is it’s just a slightly different thing here than maybe, say, the original study that you were referring to, because that’s using prebiotics or probiotics after the treatment.

DrMR: Right.

DrAS: I think what people are getting all excited about is, well, if I change my diet or use the prebiotics during, could it make the antibiotic or herbal antibiotic more successful? It’s just like a slightly different thing, a slightly different mechanism of action.

Now, just changing back and going to the probiotic subject, that’s another hotly contended one because we have these studies that say, hey, they seem to really help in SIBO, and at least they don’t hurt. There are few studies that show that they didn’t help, but if they didn’t help, it doesn’t mean they hurt. And then we have clinicians like Dr. Pimentel saying, no, he thinks they do hurt, and don’t use them. That is just so confusing, you know?

DrMR: Right. Well, the way I look at this is there’s very, very strong evidence for supporting probiotics in treating IBS.

DrAS: Yes.

DrMR: And to me, I think it’s really hard to argue against that because if really what patients are after is elimination of their symptoms, then the IBS studies are where it’s at, right? If someone’s SIBO labs became negative but they still had all the IBS symptoms, would they be happy?

DrAS: Right!

DrMR: No! We have really high-level scientific data. These two meta-analyses I put in here have examined probably over 30 randomized clinical trials using probiotics in the treatment of IBS and shown pretty good effectiveness, so I’m not sure where Pimentel’s recommendation comes from there, and I wonder if perhaps he’s a bit more kind of traditional medicine based and maybe he just doesn’t have much comfort or agreement philosophically with probiotics. Maybe that’s where that’s coming from. Maybe it’s from his clinical experience, I’m not really sure, but certainly they seem to be helpful for the vast majority of the patients that I’ve seen, and I believe you’ve had a similar experience, Allison, and then the studies seem to be very well supportive.

DrAS: I agree. Yeah, hopefully he’ll come on your show and you can ask him and really get into it so we can all hear why he thinks that. What I do—and I have a feeling you do the same thing—is I try them in many people. I try certain ones based on the individual, and then if they don’t help or if they aggravate, well, then we don’t do them. We just go case by case and check on the person. Many patients get upset because they find probiotics haven’t helped them and, in fact, have made them worse, and so first of all, I take a look at which ones it was. I mean, possibly there was an ingredient in there that was aggravating them. But certainly there are some people where probiotics really do seem to aggravate them, and, OK, then we just don’t use them in that person.

DrMR: Right, and I would agree with you that there’s always something that can aggravate someone. There’s almost nothing that I use as a treatment that never causes a reaction in anyone.

DrAS: Right!

DrMR: But I do think as far as probiotics go—and I’m not sure if you’re seeing this same thing because we have maybe slightly different populations that we work with—but I would have to say for 90 percent of patients, probiotics seem to be either helpful or cause no reaction. Are you noticing something similar there or something different?

DrAS: I have a little lower rate on that because I do see such extremely sensitive patients.

DrMR: Sure.

DrAS: My rate used to be more like yours, but as my cases have gotten more challenging in SIBO, I think it might be more like 70 percent. Either they don’t harm or they give mild benefit. There are always those outliers where it’s a miracle, and then you’re thrilled, but that’s not so common.

DrMR: Gotcha. And there’s something else that maybe we’ll do another podcast in the future that we’ve been kind of going back and forth with some emails, which is different types of probiotics that are either heterofermentative or homofermentative. I’m thinking that if we can find the right blend of probiotic that has the right gas-producing or non-gas-producing profile, that we may be able to find benefit for even the more sensitive patients with a probiotic, but that’s something that we’re still trying to work through, I think.

DrAS: I have, actually, lots to say on that, but maybe we’ll save it for another time because I’ve experimented a lot with that.

DrMR: OK, good! Yeah, maybe another time because I feel like if we go down every tangent, we will be on the phone for three hours, which I would love, but I think some people might be asleep by the end of that.

DrAS: Yeah!

DrMR: All right, there are a couple of other things that I thought were noteworthy and that maybe we could kind of talk through.

Probiotics as Antibacterial Agents

DrMR: One of the things that has been interesting to me that I’ve come across as I’ve been working toward the completion of the book is there’s been some discussion that probiotics may actually be antibacterial agents. There are a couple of things that I want to kind of come to with this, but one of the things that is discussed along the same lines of thinking is that probiotics also may have more of an impact on the small intestine than they do the large intestine (7 Trusted SourcePubMedGo to source). This is more of a theory. It’s very hard to definitively answer this question, but the theory comes from the fact that the more complex the microbiota is in a certain region, the harder it is to make an impact on it. This is why probiotics don’t really recolonize you, but you can recolonize with something like a fecal microbiotal transplant. If you introduce something very, very complex into an already complex ecosystem, then you can have an effect, but probiotics don’t seem to be complex enough. There’s not enough bacteria to really cause a major shift. However, because the colonization density of bacteria is much, much lower in the small intestine, it’s been proposed that probiotics may exert more effect there because there’s kind of less competition.

It’s almost like if you were trying to move into a community and it was a community that wasn’t settled, like the rural countryside. It would be easier to move in and have an impact there than it would maybe in downtown Manhattan. Moving in might not be the best analogy because, in my view, probiotics don’t appear to really colonize, but the point here I’m making in a very kind of roundabout way is because the small intestine has a lower bacterial colonization density, probiotics may be able to have more of an impact on the small intestine than on the large intestine.

Allison, what are your thoughts on that?

DrAS: I really don’t know. I don’t know if that’s true or not. I definitely think it’s true in the way that you said that FMT will have more of an impact than taking a probiotic, but I’m not sure if probiotics can truly impact the small intestine more than the large intestine. I’m not sure.

DrMR: Yeah, and I don’t think we really know. It’s just an interesting theory that’s being put out there, and maybe it accounts for some of the benefit that we see with probiotics in IBS. Maybe these probiotics are having an antibacterial effect on the small intestine, which has been shown in some of the SIBO studies.

DrAS: Well, it’s a for-sure known thing that probiotics are antibiotics. They secrete bacteriocins, which are antibiotic compounds, and other antibiotic compounds. That’s a for-sure thing.

DrMR: Right. That’s an excellent point.

Probiotics and Colonization

DrMR: What is your take, Allison, on if probiotics can colonize or not colonize? (8.1 Trusted SourcePubMedGo to source) (8.2 Trusted SourcePubMedGo to source) (8.3 Trusted SourcePubMedGo to source)

DrAS: I think some are shown to be able to and most can’t. I think the general idea of probiotics throughout the ages is that they don’t colonize because that’s why people would eat them in every meal.

DrMR: Right.

DrAS: That’s the traditional way people consumed probiotics, mostly in condiments. Why would they be doing that? Why would they be taking them in every day, multiple times a day, if they only ever had to take them once?

DrMR: Right. Good point. Something else there that might be interesting… This is kind of food for thought for people. They’ve done experiments with what’s called “heat-killed” probiotics, where they heat up probiotics to the point where they kill all the live cultures, the live strains, and they’ve actually found pretty impressive results with using heat-killed probiotics, which suggests there’s more to probiotics than just the living impact that they have (9.1 Trusted SourcePubMedGo to source) (9.2 Trusted SourcePubMedGo to source) (9.3 Trusted SourcePubMedGo to source) (9.4 Trusted SourcePubMedGo to source) (9.5 Trusted SourcePubMedGo to source) (9.6 Trusted SourcePubMedGo to source)It may have to do with immune system signaling or what have you, but I thought that was interesting. Do you have any familiarity with that?

DrAS: I do. When I first came across that, it was mindblowing to me.

DrMR: Yeah.

DrAS: The books and studies I was reading on that suggested that it was a lot of the compounds that the probiotics secrete into their media that you are taking, and so it’s more those items, those metabolites and things, that are affecting us than the living bacteria themselves. I’m just like you; I’m familiar with that, and it’s pretty interesting because one of the arguments against a lot of commercial probiotics is that they won’t survive past the stomach—some do, some don’t—or that the quality is so low. How do you know in all these different products that they might be dead? And it’s like, well, apparently it doesn’t matter!

DrMR: Right! Yeah, and I think one of the things that may be useful to people with all this is that sometimes patients freak out. Let’s say our office is shipping someone a probiotic, and the ice pack has melted. We’ve had people call the office pretty distraught. “Oh, my God! The ice melted! Can I return the probiotic? It’s probably no good.” I have to remind people that it’s OK if even a live probiotic is out of the fridge for a couple of weeks. In my opinion, it doesn’t seem to make much of a difference at all, and like these heat-killed probiotic studies are showing, it may not even matter if they’re even alive. Yeah, we may not have to be so fastidious about probiotic maintenance, I guess you could say.

DrAS: Good point.

Carbohydrate and Prebiotic Responders in SIBO

DrMR: Let’s talk now about what I’m terming—and I hope we can come up with a better term for this at some point—carbohydrate and prebiotic responders in SIBO. We spoke a few months ago, Allison, and have kind of been comparing notes on this, but something I’ve been noticing clinically is that with some patients prebiotics seem to really be helpful for SIBO. There’s a lot here that I think we have to learn, but what I have noticed is with some patients that have a lower level of SIBO and that have reported they seem to do better on a little bit more carbs rather than being low carb. For people with this presentation, I’ve experimented with using prebiotics, and for the patients that I’ve done this with, for the most part, the prebiotics seem to really kind of help. So I think that there’s a subset of people that may do really well with prebiotics.

What are your thoughts on that? I know you have a lot to say, and we may need to do a follow-up episode on some of the stuff we talked about before we went on air, but what are your thoughts about, I guess, prebiotics in SIBO?

DrAS: Well, let me just first go to the thing you just described because when you told me that you were doing some of this experimenting and seeing this sort of subset—it’s kind of like a different type of SIBO patient—I was very interested, and so I looked to see if I would have any patients like that, that would sort of fit that idea. Like you said, sort of mild gas levels, not horrendous symptoms, kind of mild symptoms—and you can let me know if I have this right—and I think you also told me that you tried some traditional SIBO treatments that hadn’t really worked.

DrMR: Yes. Thank you for mentioning that. I left that out.

DrAS: Yeah, and so it’s like they were different. I even remember you saying that you wondered how much was it all about the small intestine, and could it be that maybe more of the symptoms were coming from the large intestine.

DrMR: Right.

DrAS: You weren’t sure, but they did test positive for SIBO, so hmm. I wound up having two patients like that, that fit that criteria, and so I tried the same regimen you were trying, which was prebiotics that are soluble fiber and FOS and I can’t remember what else. This is the type of thing that would really be very painful and create terrible symptoms for most SIBO patients. And it worked! It worked in the people that fit that criteria.

Then there was a third case I tried it on that also fit that criteria, and it didn’t work—as we would expect.

DrMR: Sure.

DrAS: This is new to us both, and we’re trying to figure out who fits this, but I was really pleased! Especially because they were people where other things I’d tried should have worked and they didn’t, so I’m really interested in this.

Now, another idea that—this is what you were referring to we were just talking about before the beginning of recording—is that I spoke to a fascinating doctor whose name I’m going to mispronounce, but it’s Dr. Jason Hawrelak. I know I’m saying it wrong!

DrMR: That’s a tough one, yeah.

DrAS: You can find him on He has just educated me on something that was very important for me to learn about and I’m so glad. Dr. Nirala Jacobi from Australia, who many people may know, she’s the one who connected us, so I’m so grateful to her. He let me know that some prebiotics might be quite helpful for SIBO because they don’t raise gas. Other prebiotics do raise gas, and some prebiotics don’t and, in fact, have been studied and shown to lower hydrogen and methane. For those of us who have been grouping all prebiotics together, which I had been and saying all prebiotics are likely or may aggravate people with SIBO, that isn’t so because there are at least two that have been shown to lower gas. I think we need to… or I certainly need to be a bit more, now, detailed and specific when I use those descriptions.

And then, of course, there’s this other thing that you and I were just talking about. In fact, there might be some people—and we have found that there are—some people with SIBO who even aren’t aggravated by the prebiotics that do raise gas. It’s just a good match for them.

Just briefly, the two prebiotics that he mentioned that don’t raise gas are partially hydrolyzed guar gum, and many people are familiar with that because there was a study done on combining it with rifaximin many years ago, and some clinicians do that regularly in their office. I tried it and I just couldn’t perceive that it gave any additional benefit to just rifaximin alone, so I stopped using it, but now I’m going to try it again because I’m re-interested!

And then the other one is a certain form of GOS. GOS stands for galactooligosaccharides. The main ones people are familiar with are stachyose and raffinose, which are in beans and certain vegetables. It’s not those. It’s a different type of GOS. This doctor was letting me know that those standards, stachyose and raffinose, do aggravate most people with SIBO, but it’s this other GOS. I don’t know what its name is, but I know it’s in a product called Bimuno.

Those are some thoughts.

DrMR: There are a few different things I’m thinking as you’re saying that. One is I think we’re learning more every day about a lot of these things, and I think we’re going to continue to get better and better with picking the right probiotics for the right cases and with picking the right prebiotics for the right cases. This is something that I’m excited to learn more about, and we will reach out and get this doc on the podcast. Also, like I like to do and all of us here on the research team that is immensely helpful for everything that we do, we like to fact check things, so we’ll probably go through some pretty robust fact checking of what this doc has to say, have him come on and talk through it, and see how everything shakes out, but I’m definitely very interested to learn more about this. It does kind of allude to something that I’ve been noticing clinically, and perhaps by being a bit more prescriptive in our recommendations, then this “carbohydrate and prebiotic responders in SIBO” subset maybe will be able to do even better.

It reminds me of something that I think is important maybe to just reiterate, which is I think that I’ve learned as much from observing my patients as I have from research and training and study and everything else. I just want to put that out there because as much as the science helps us—and I think everyone listening knows how much I lean on the science and review the science and pick through it—it’s also important to not be limited by what the science says, because I think when we do that, we limit our ability to think creatively, to problem solve, and to think progressively and outside of the box.

That’s how I’ve stumbled across the prebiotic piece in SIBO. The thinking that I went through was, well, there are these patients that don’t really seem to be responding well to the standard treatment. What do we have to lose by cautiously trying a prebiotic? Maybe there’s more to this case than just SIBO. I always try to keep in the back of my head that there are things that are important right now that we don’t know how to test and that we don’t have lab values for, but we’ll probably discover in five or ten years, so I try not to be limited just by what we know now, but to be able to think a little bit more openly on these things. My thinking to myself was, well, they haven’t responded to the other treatments. Prebiotics seem to be able to help various functions in the gut, so maybe the prebiotics will modulate the ecosystem in such a way that will produce a health benefit. So let’s slowly and cautiously work into this and see what happens. There you go. We had a few patients that this really helped, and I’m hoping that we’ll learn even more about this with every passing day.

What do you think, Allison?

DrAS: That was so wonderfully put. It’s such a different thing to be a clinician than just a scientist!

DrMR: Right.

DrAS: So often we find where the studies are telling us things that don’t at all fit our experience either in the clinic, and it can be so frustrating, but we have to go with what’s in front of us, with the patients. I think that makes for, sometimes, if I dare say, the difference between the most sort of standard, stereotypical Western medicine doctor, because often they will just go with studies even if their patients are saying, “This isn’t jiving for me.” We have to go with what we see in front of us.

Also I love that you do the fact checking because what I just shared with you about this doctor that I spoke with, I haven’t even delved yet into the studies that he was mentioning, so I haven’t found it to be true yet for myself. Nor have I had a chance to try it in patients. So I’m going to try it. I’m going to try it on people whom I think it can work for, and what I mean by that is these prebiotics that he’s finding many people with SIBO can accept. Will I find that to be true? I don’t know, and especially in my patient population which is extremely sensitive and challenging, so I’ll just have to report back.

DrMR: Yeah. Well, I agree and I think it’s really important to be progressive and open minded but also skeptical because anyone can make a claim.

The Importance of Fact Checking

DrMR: Here’s maybe an example of why I think that fact checking is important. I’m currently writing the section of the book on stomach acid, and I have a book in my bookcase all on stomach acid, written by a very highly regarded functional medicine doctor. He was talking about PPIs and acid-suppressing drugs. There are two main classes; there are histamine antagonists and there are proton pump inhibitors that essentially decrease stomach acid production. He was making a case, and he cited three or four studies showing that when we suppress stomach acid and we have low stomach acid, that actually may cause reflux or heartburn because if you don’t have adequate stomach acid, what’s called the lower esophageal sphincter, kind of the valve between the esophagus and the stomach, can’t close. The valve won’t close if your stomach isn’t really acid because you have to have acid to signal that valve to close tight. He proceeded to describe how if we take acid-reducing medications, that will throw off that sphincter. I checked his references, and all of his references showed the exact opposite, where it’s actually been shown that acid-lowering medications increase the tone of this sphincter, and it may through how it affects a signalling hormone called gastrin.

I’m not saying I’m endorsing acid-lowering medications, but I think it is important that we fact check because what this may look like in the real world and why this may have some relevance is that if someone thinks that some symptoms of indigestion, for example, are solely attributed to having low acid and they take megadoses of acid, if they actually have an ulcer that’s the reason for those symptoms, they could be making themselves worse. So I think it’s important for us to be open minded and progressive but also to be a bit cautious and to fact check things because for that patient who maybe has dyspepsia and they have maybe a little bit of upper abdominal bloating and a little bit of indigestion, that may be helped by acid, certainly, but those are also loosely the symptoms of an ulcer. If this person was getting a one-sided view on this, they may miss out on the fact that even four weeks on one of these medications has been shown to have a 90 percent heal rate for ulcers, and that may not be a bad short-term intervention.

In a very long tangent here, I think it is important that we fact check because sometimes the references are not correctly cited, and if no one is fact checking, then we could all be doing a treatment that may harm people because no one actually fact checked the fact that there was a mistake and no one caught the mistake, but everyone was referencing the mistake.

DrAS: This example that you gave is why I like testing. So many diseases, the symptoms of them could be from one cause or the exact opposite cause.

DrMR: Right.

DrAS: That’s why I like testing. Acid reflux is a prime example because the symptoms of reflux could be from too much acid or too little acid. Standard Western medicine thinks everybody has too much acid. Standard alternative medicine thinks everybody has too little acid!

DrMR: Well said!

DrAS: And in fact, it could be either, it doesn’t matter who you subscribe to, and we have to test it and figure out which.

DrMR: Yeah, exactly. This is why we get along so well, which is because we’re not operating in one box to the exclusion of the other. We really have the patient’s well-being as our primary objective. Whether they achieve that well-being through stepping through the conventional box or the alternative box, we don’t really care.

DrAS: Exactly.

Dietary Recommendations for SIBO

DrMR: Is there anything else that you think is kind of important to mention or that you’d like to cover on this? Maybe coming back to our original preface of, should you eat FODMAPs while you’re treating SIBO, I think we’ve already answered that question, but is there anything else you’d like to offer people or remind people of within this realm?

DrAS: Yes. You know, I just want to sort of discuss that through a little bit, about which way to do the diet, because I think people are really confused. I’ll just give some examples.

The way that I had always done it is similar to you. I had not even thought about increasing someone’s carbohydrates during treatment with the idea of, oh, it’ll make sure the bacteria is replicating. The way that myself and my practice partner, Dr. Sandberg-Lewis, had always done it is if someone wasn’t on a SIBO diet yet, advise them to begin practicing and sort of slowly get themselves learning and on the diet during the treatment, whether that’s antibiotics or herbal antibiotics, because it takes some time to learn a new diet, with the goal of being on whether SIBO diet it was we were choosing for them circumstance, to be on it by the time they finished their treatment. Very similar to you, so that by the time it’s over, we’re sure they’re on it.

I knew I was going to be talking to you, so I asked Dr. Sandberg-Lewis about that, what he thinks about this idea. Basically his response is that he’s been doing it like that for five years and he gets great results, and it never even occurred to him to do anything different because he has a successful treatment rate. It’s not even a thought. Nothing has inspired him to think he should do it differently.

I asked Dr. Nirala Jacobi about it, and she had such an interesting comment. She said, “Well, I didn’t do that for candida. I didn’t try and feed the candida yeast!”

DrMR: Right!

DrAS: “Nobody treating candida tends to do that. Everybody puts them on a candida diet, a low-sugar, low-carb diet. Why would I do it for SIBO?”

Now, I don’t actually know. I’m not a yeast expert, and I don’t actually know the mechanism of action with antifungals, so I don’t know if they way they work they need the yeast to be replicating. I don’t actually know that. Maybe there’s a difference here. But Nirala actually uses a stricter SIBO diet than myself or Dr. Sandberg-Lewis, and she reports great results. She sees a broader spectrum of patients than I do. She sees challenging cases like I do, and then she sees simple cases. She has a very broad spectrum. She’s also still a primary care physician, which I’m not. I’m just a specialist. So she sees all walks of life.

DrMR: Right.

DrAS: And she has really good results, and she herself was not inspired to ever change this.

Now, what I wondered about is, because Dr. Pimentel is suggesting this is what he thinks works, and so it’s like, hmm, well, I don’t know. Maybe what I should do is do an in-between method. I rarely these days see somebody who’s not already on a SIBO, but when I have that opportunity, if they’ve never changed their diet, then I think, “OK, well, don’t change your diet yet. You can just do whatever you’re doing while you do your treatment, and then we’ll get you on some sort of SIBO diet, maybe low FODMAP or Cedars-Sinai, afterwards, after your treatment.” I’ve suggested that to some people, but honestly I don’t have enough of them to give you my comparison yet.

DrMR: Right.

DrAS: But I guess I did just want to say that part of the reason that this seems sort of a controversial thing to me is because after Dr. Pimentel suggested this at the first SIBO Symposium—or at least he reported this is how he does it—I then, over the next, like, six months, heard from many people who had tried it, and they told me that it didn’t seem to be helpful. What they meant was that they couldn’t perceive that it made their antibiotic or herbal antibiotic work better, and in fact, most people reported that it seemed to worsen them. These are not people that I did this with. These are people that had tried it with their own doctors, or doctors that had tried it with their patients, and they were reporting that to me.

What I don’t know is I don’t know, well, what foods did the people eat? This is just hearsay, so there’s a lot I don’t know, but the one thing I was able to figure out is that for the most part, these are people who had already been on a SIBO diet of some sort, some sort of low-carbohydrate diet, and then they increased their carbs. Now, like I said, I don’t know what they ate. I think we would all think that maybe they would have symptoms during the treatment, but the real issue was they didn’t think it made the antibiotics or herbal antibiotics work better. So this became sort of a controversial idea in my mind because honestly I’ve never heard such a high quantity of feedback on one subject than I did on this.

DrMR: Sure.

DrAS: So I thought, geez, this is really weird. What I took from it was maybe it’s for the patient population that’s already been on a SIBO diet, on a restricted-carbohydrate diet, that this is really not the best idea for. So currently I do the same thing in a way that I’ve always done. I just advise people stick with the diet because most everyone I see is already on a diet. Most of them have gotten it pretty figured out what diet works for them, and I just tell them to stick with whatever doesn’t bother their symptoms.

One other idea here is the idea of starches because some people think, well, I’ll add in starches, white rice or white potato, or if gluten is tolerated, white wheat products. However, for me, I do that with everyone anyway on a SIBO diet. I pretty much ask most everybody to try those foods and see if they’re tolerated. I find a lot of people can tolerate white rice or white potato. But what I don’t do is tell them to eat it when they’re on antibiotics or herbal antibiotics if they know it bothers them. I just keep people on a diet that doesn’t trigger their symptoms, and I myself have never felt like I needed to change it. This comes back to sort of your original idea. I just don’t think it’s make-or-break!

DrMR: Right.

DrAS: There are other issues here that are challenging to us rather than this.

DrMR: Yeah, exactly. There are a couple of things. One, in the grander scheme of treatment, there are more important battles to fight and to focus on, definitely. I totally agree with you there. And then the other is maybe we don’t need to be very SIBO-centric in our eating. This is kind of reiterating what you said a moment ago, but I prefer to get someone on a diet that they feel well on and use that as the diet that we use during and after treatment predominantly. Personalize a diet to the patient, and don’t try to fit the patient in the diet box that I have a preference for. Sometimes this looks like paleo. Sometimes this looks like more of a ketogenic diet. Sometimes people don’t do well on low carbs and they do better on more carbs. I truly think that the diet a person tends to feel the best on—or maybe said another way, the least symptomatic—is probably the diet that’s going to give us the highest likelihood of treatment success, because if you’re feeling good on something, it’s probably good for you, and it’ll probably make treatment more successful. And again, maybe we shouldn’t be thinking about this in a solely SIBO-centric way—these foods feed SIBO; these foods don’t feed SIBO—because there are many other things that we have to account for: someone’s metabolism, their ability to process glucose, levels of inflammation in the intestines, which may be provoked by fiber. That’s why I think just giving the patient some general guidance on their diet and letting them settle into what feels best is probably going to be the best approach overall.

DrAS: I couldn’t agree more. Well said!

DrMR: Thank you! This is why I love having you on the show! And by the way, you did a really great job speaking to some of our cohorts before coming on the show. I don’t know if I should pay you for that or if you’re going to invoice me for that later!

DrAS: Well, I just wanted to hear what other people are thinking. That’s all.

DrMR: Sure.

DrAS: There are other people that don’t think the way I just have said, and they should have their day in the sun, too.

DrMR: Yeah, well, I’m going to try to get Pimentel on here at some point. He’s one of the people I’ve been meaning to reach out to and get on here because there are a couple of things, that being one, the diet and then also the prebiotic synergy, that I’d like to get his take on and then the probiotic piece, too. Those are two things I’d like to get his perspective on and try to dig into, especially with the probiotics, if that’s an issue of personal preference or if there’s been some notable clinical observations that have prompted that.

DrAS: Something that’s really interesting that you’ve been mentioning throughout the show, that we can all think about, is if there are people who see a lot of SIBO or whatever disease or disorder you’re thinking of, there are a lot of people who have experience in that, and there are certain treatments that they disagree on—and by “disagree,” I mean they have some different experiences.

DrMR: Sure.

DrAS: One thing we could think about that is that it probably might mean that it’s not a make-or-break thing. Like, hey, if the exact opposite thing works for one person than the other, then maybe it’s not that key.

DrMR: Well said. Very well said.

DrAS: And then the other thing we could think of would be they might have a pretty different patient population, because that does happen. We draw different people to us. Just as an example, I have seen relatively few overweight SIBO patients. I know there are overweight SIBO patients; I just don’t tend to have them in my practice very much, whereas my colleague, Dr. Sandberg-Lewis, has seen many. So he might have some different experiences with treatment based on that.

DrMR: Yeah, I’ve actually seen a fair number myself, and I think we’ve done at least one of our patient follow-up stories where a gal lost a pretty good amount of weight. I’ve definitely seen a number, not the majority… but actually, come to think of it, I probably see slightly more overweight SIBO patients that seem to lose weight from treatment than I do underweight.

DrAS: I’d have to say I see very, very few overweight.

DrMR: The opposite, yeah.

DrAS: Yeah. Then that might throw off some of our experiences, so that’s the other thing that might make a difference between doctors that are seeing different things. But I think the other one might be pretty important, too, that it’s not that key.

DrMR: Yeah, I think actually that’s worth reiterating, that if there is controversy over a certain treatment, it probably means that it’s not make-or-break or not that impactful because the only way that could exist would be if it wasn’t truly super effective, whereas if something was clearly effective, you’re probably going to see agreement on it. I think that’s actually really, really insightful.

DrAS: Thanks! See? This is why I like coming on your show!

DrMR: Oh, man. Well, we have a mutual crush going on here, Allison. Is there anything else that you want to mention before we wrap it up?

DrAS: No, that’s plenty.

Episode Wrap-Up

DrMR: All right. Is there anything that you’re working on that you want to make people aware of? And would you also, please, remind people of your website?

DrAS: Oh, yeah, my website is, and, no, there’s nothing all that other key I need to say.

DrMR: Cool. I actually want to thank you. You gave me quite a few mentions in your last newsletter, so thank you very much for that. I appreciate you sharing everything that we’re doing over here.

DrAS: You’re welcome!

DrMR: Cool, and I will see you at the SIBO Symposium (10) in not too long, which I’m very excited about, by the way.

DrAS: Excellent! I’m looking forward to it.

DrMR: For people listening, I’m, of course, biased, but it’s one of my favorite symposiums, so if you’re thinking about doing something to learn more about SIBO, I would highly, highly recommend checking out the SIBO symposium. You can go in person and meet both Allison and me face-to-face, or you can attend digitally. I know you’ll be presenting multiple pieces, I believe, and I’ll be presenting a few different pieces myself, which I’m really excited about sharing, so I think it should be a really, really fun event. And the food up there is really, really good, too.

DrAS: Yeah! It’s all SIBO friendly, so, yes, all are welcome.

DrMR: Cool. Well, thank you again so, so much, and I look forward to the next time we do this again.

DrAS: Take care!

DrMR: All right, thanks. Bye.

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