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Should You Treat SIBO If You Have the Symptoms But Your Labs Are Negative?

Should you treat SIBO if you have all the symptoms but your SIBO labs are negative? Let’s discuss an approach for navigating this and close with a few reflections on life.

If you need help deciding to treat SIBO, click here.
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Episode Intro….. 0:42
Listener Question….. 2:32
Things to Consider Before Taking an Antibiotic….. 5:06
Limitations of Lab Testing….. 9:16
Modulating the Microbiota….. 11:15
Episode Wrap-up….. 16:06


  1. SIBO-Specific Diet: Food Guide by Allison Siebecker
  2. Prescript-Assist
  3. Primal Defense
  4. Digestzymes

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Should you treat SIBO if you have all the symptoms but your SIBO labs are negative? 

Episode Intro

Dr. Michael Ruscio: Hey, everyone. Welcome to Dr. Ruscio Radio. This is Dr. Ruscio. And I am actually flying solo today. But we had a listener question come in that I thought would be interesting to answer and a couple other thoughts I thought we could cover. So I guess we will jump in.

Before I play the listener question, I just wanted to thank everyone for their continued support. The podcast is growing like crazy. The newsletter is growing like crazy. People are commenting on most of the posts that we put out now.

And it’s really nice to see people commenting back and forth, supporting each other, sharing information, having healthy discussion about some of these things.

So it’s such a great community of people who are kind of coming on board. So thank you, guys, because it makes all the hard work to do this stuff really worth it when it seems to really be helping people. So thank you!

An update on the book, which I know I’ve been talking about forever. I anticipate the book to release early—and hopefully January or February—of 2017. I am almost done. I am super happy with how it has come out. Of course, there is still a lot of work after the first draft is written that has to be done.

But I really think we’ve laid out a really good, responsible review of the gut, review of the literature of the gut, given people a responsible action plan to walk through to try to restore their gut health. And it could be a good guide for both patient and doctor alike to help with such an important area of health, which is the gut. So hopefully, not too long until that comes out.

So let’s play the listener question.

Listener Question

Listener: Hi, Dr. Ruscio. Love your podcast. I had a question for you. My GI has prescribed Xifaxan for me as something to try to alleviate my GI symptoms even though a glucose SIBO breath test came back negative. My methane was, in fact, zero. And hydrogen was 03 parts per million ppm, I think is the measurement.

If you were a patient, would you feel comfortable taking a round of Xifaxan without a positive breath test? I’m unsure if I have SIBO or not because some of the symptoms match. But they also match other conditions. From your podcast and information I’ve read about Xifaxan, it seems it wouldn’t hurt to try to see if my symptoms improve. But I wanted your opinion. Thanks in advance for addressing my question!

I was so impressed by your podcast, I have signed up to become a new patient and am very excited to talk to you in person in a couple months. Bye. Thank you.

DrMR: Alright. So there’s a question. And that’s, I think, a really good question that we can hopefully take away some valuable points from. So really someone—I’m assuming; we don’t know this for a fact, but I’m assuming—has many of the symptoms of IBS yet does not have SIBO.

So IBS—some of the typical symptoms that can manifest there could be altered bowel function—meaning decreased frequency or increased frequency, constipation, diarrhea; altered stool consistency; abdominal pain; bloating; maybe even some indigestion symptoms; maybe occurring along with this, reflux. So typical gastrointestinal-type symptoms—gas, bloating, loose stools, diarrhea, constipation, heartburn, reflux, bloating, pain.

So did a SIBO breath test. And the SIBO breath test came back negative. But rifaximin, or Xifaxan, is FDA approved for diarrheal-type IBS. So it begs the question, could an empiric trial of the antibiotic be worthwhile. And I think it can. But it’s also important to qualify oneself or try to put someone in a position where they’ve done all the other groundwork and the next logical step would then be an antibiotic or an herbal anti-microbial.

Things to Consider Before Taking an Antibiotic

DrMR: So things to consider before an antibiotic would be Paleo diet, and if you’ve done Paleo and that hasn’t helped, try going low-carb Paleo for a few weeks and see if that helps, because there are definitely people that do not do well with fruit, starches, grains—even the gluten-free grains, even potatoes for some people—sweet potatoes and potatoes. So that’s an easy way to weed out a lot of the things that can be problematic for some, especially because many of these more carb-rich foods, I guess you could say, can feed things like SIBO or candida.

Now, if you’ve tried low-carb and still haven’t gotten a lot better, there are two other derivations that you may want to try. And I would say try them for a couple weeks. You don’t have to try it for months—at least a couple weeks. And if you’re starting to respond, then ride the wave. And if you’re not really responding, then move on. But the first would be low-FODMAP. And second to that, you may want to consider low-FODMAP with SCD. And Dr. Allison Siebecker has put together a nice list that combines that for you that’s easily available on the internet.

But this approach would now be more specific to limiting fermentable carbohydrates, I guess you could say, and limiting carbohydrates that people have a hard time digesting. So if a lot of your IBS is being driven by a different type of carbohydrate malabsorption—fructose malabsorption, lactose malabsorption, what-have-you—then this could very easily help with that as can a low-FODMAP diet help with potentially trimming back SIBO. It certainly has been shown to be helpful for IBS symptoms.

So from a dietary perspective, there are a few things that you can fool around with there to see if you can get to the desired level of improvement.

Other things to consider—how does your lifestyle look? If you’re not sleeping enough and you’re stressed, that can definitely cause or provoke many of the symptoms of IBS. Alcohol, coffee, processed foods, overeating—all those things also. So I’m assuming these things have been addressed. But they’re important to reiterate.

Additionally, have you tried a probiotic? A lactobacillus/bifidobacterium blend is a great place to start. A Saccharomyces boulardii probiotic is also a good place to start. Additionally, you may want to try a soil-based probiotic—something like Prescript-Assist or Primal Defense. And throw in with that a digestive enzyme and/or acid formula. We use a formula that combines hydrochloric acid, pancreatic enzymes, and bile.

So all of these have been treatments that have been shown to help with IBS. The least data supports digestive enzymes, but there’s some. And there’s a nice amount of information supporting probiotics, low-FODMAP, SCD, and lifestyle interventions. So definitely, these are things that are noninvasive that can be used to treat IBS. So I would start with those.

So if after all of that you’re still not feeling much different, then the question is, do we treat the SIBO even though the SIBO hasn’t been found on the labs? And I think you can at that point. Now, you have options. You may elect to try an herbal antimicrobial instead of an antibiotic if you wanted to try something that’s a little bit more mild, although that being said, I think rifaximin seems to be very well tolerated by patients. The reported side effect profile in the literature is very minimal.

And patients generally seem to do pretty well with it in the clinic. So it seems to be pretty safe. It doesn’t seem to provoke the secondary overgrowth or imbalances we can see with other more systemic or absorbable antibiotics. So I think it’s pretty safe.

Limitations of Lab Testing

DrMR: But regarding lab testing, it’s important to remember that there are things that can be happening in the body that we can’t elucidate with lab testing. Lab tests are not perfect.

So this is where I think the context is really important. Should we rush in there with an antimicrobial intervention, like an herbal, or an antibiotic if we haven’t gone through some of the dietary, lifestyle, and probiotic, and enzyme interventions that I discussed a moment ago? Probably not. We want to qualify someone.

So we start there. And if they’re still not responding fully, then we can move to the antimicrobial approach of an antibiotic or an herb. And this is because there may be something there in the labs that we’re not able to see.

There may be hydrogen sulfide SIBO. There might be SIFO (small intestinal fungal overgrowth). Maybe there is toxoplasmosis gondii that wasn’t found or blastocystis hominis that can be a problem for some. Or candida. Or H. pylori. So there are certainly things there that can be a problem.

There may just be a commensal—or with the players that should be, there may be an imbalance in the commensals. They may not be decompartmentalized as they are in small intestinal bacterial overgrowth.

But the colony may be off. And in my opinion—and there is some published literature that supports this—you give the microbiota a little nudge with herbal antimicrobials or antibiotics. And that nudge can allow it to recalibrate to a better equilibrium, so to speak. So that may really be the utility of this kind of approach.

So, yes, I think if you’ve gone through all the qualifiers that I mentioned, you’re okay to try Xifaxan.

Modulating the Microbiota

DrMR: Now, this also reminds me of looking at the microbiota like an ecosystem or like a garden. And when we have patients where the labs and the symptoms don’t match, we oftentimes fall into a more empiric type of treatment. So treat in one way, and if the patient responds to that treatment, continue treating in that way. And if they don’t, change your tactic.

And there are a couple different directions you can really nudge the microbiota—the antimicrobial direction. And low-carb would be somewhat antimicrobial. Low-FODMAP can be considered, in my opinion, an antimicrobial. SCD can be a little bit antimicrobial because these diets aren’t great at feeding bacteria.

A probiotic could also be considered antimicrobial. I think a probiotic could be put in many different camps of utility. But probiotics have been shown to be an effective treatment for SIBO. They help crowd out candida. They can aid in the assistance or clearance or rebalancing of H. pylori and other amoebas and protozoa. So they certainly have a lot of documentation as being antimicrobial. So we can try a nudge in the antimicrobial direction.

Alternatively, while it’s a lesser number of people in my observation—and I think the literature also supports this—but we could and nudge in a pro-microbial direction, which would be starches, fibers, fermentable substrates like FODMAPs or supplementing with a prebiotic or a fiber supplement or resistant starch or eating foods that are high in resistant starch. For some people—I’d say a smaller number—but for some, this really seems to help with the gut. And for other people, this will make them worse. So sometimes, we have to just ask the gut, “What direction do you need to be nudged into to get the response?”

And there’s also the piece to keep in mind, with some IBS, especially if it’s a more diarrheal-type presentation, that can be in some cases a low-level inflammatory bowel disease that needs a diet that’s a little bit lower in insoluble fiber.

And Susan, our podcast host, has discussed how she has to be careful with how much especially insoluble fiber she ingests because that can be problematic for those that have inflammatory bowel disease. And also, I should mention, the antimicrobial approach tends to be very helpful for many with inflammatory bowel disease like Crohn’s or ulcerative colitis because we’ve seen low-FODMAP diet and SCD diets used successfully in those conditions.

So I hope this is making at least a small amount of sense in terms of thinking about this—if the labs can’t help you—thinking about this in terms of what direction do we need to nudge the gut and be monitored and try to learn from your response what works and do more of what works.

And that may not sound incredibly scientific. But as I’ve learned more as a clinician, I’ve learned that you can’t—you just can’t exist in this space of only making decisions based upon lab testing. And the more I learn and the more I see people touting that kind of approach on the internet, I question how many patients they’ve treated because in time you just will see there is a subset of patients that the labs and the symptoms don’t match. And then you have to be more empiric in your treatment approach.

So I think that’s an important thing for us to keep in mind, especially in functional medicine as we try to be very objective and evidence based in a lot of circles. It’s important to do that but not to be evidence limited, I guess. And so if we don’t have laboratory evidence, we can’t let that limit our decision-making and thinking process. We have to keep thinking.

So those are the main things that come to mind in regard to your question. And hopefully, that will be helpful. If you’re going to be a patient in the clinic, then we will be going through that process essentially together. And it may be easy. It may just be something was missed, and we’ll do some lab testing, find something. And it’ll be as easy as that. It may come to a position where the lab testing shows nothing and we have to go into this more empiric type of approach.

But I think as long as you have a doctor who is knowledgeable about the different treatment options that can modulate the microbiota and they will use those in a logical sequence with you and monitor your response throughout and adjust the treatment and personalize it, then I think you have a chance of really coming out on top.

Episode Wrap-up

DrMR: So that is the long answer to, should you treat—I’m assuming—the symptoms of IBS with rifaximin (Xifaxan) if you don’t have a positive SIBO test. So yes, but you have to qualify the person for that.

Before we close, I wanted to share something on more of a personal level that was an interesting experience for me. And I figured it may help others in some regard, or at least, I hope. A good friend of mine, his father passed away very suddenly and very unexpectedly just a few weeks ago. And he was young. He was in his mid-50s and just dropped dead.

And I was sitting at the funeral service. And I couldn’t help but be struck by a few things as I’m watching my good friend in tears reading the eulogy for his father to how important it is to spend time with the people in your life that you love, because I was just getting teary eyed watching how much my friend would have given for another night, weekend, day, breakfast, coffee with his father.

And it really made me step back and take stock of—yes, I’m working my butt off right now with the book and the website and the research and the studies and the lecturing and the clinic. But I need to do a better job of letting go of some of those things sometimes so that I don’t let those things crowd out family, friends, and just how really important that is and how important it is to let the people in your life that you love know how much you appreciate them.

And that’s another thing that really made me see how easily we can take for granted having a father, friend, mother, cousin, sister, sibling, what-have-you. So if you haven’t been spending enough time and if you haven’t been letting people know that you appreciate them, I’d take a second just to let them know because certainly it’s only going to make them feel good. And it’ll probably make you feel good at the same time.

What’s that old saying that life is like a mirror—or the world is like a mirror. Whatever you show the mirror, you’re going to see back reflected at you. So if you show appreciation to others, that’s going to come reflecting right back to you.

The other thing this made me think of was not sweating the small stuff. Again, sometimes, I get pushed off maybe spending as much time with friends and family because of all these commitments that I have. And sometimes, admittedly, these are just little things like the study design needs tweaking and it has to be submitted by this date. Or this thing failed at the office. Or this website thing isn’t working properly.

And it’s easy to get frustrated by those things and let those things take you out of the time that you have with your loved ones because you’re just using all your free time to service these tasks. But it really made me take stock of how important it is to sometimes let those small things go so you can spend time with the people in your life.

So hopefully that will inspire you to tell people whom you love that you love them, you appreciate them. Spend some time with them. And also remember to do what makes you happy. Love people. Treat them well.

And, to come back to the whole purpose of this podcast, if you have SIBO or IBS, take the appropriate steps to address that because that will definitely help you have more energy, vigor, and vitality to bring to your life and your loved ones.

So this is Dr. Ruscio. And let me know what you think of this solo format—love it, hate it, don’t really care—because I might do these a little more often when it’s really challenging for me and Susan to coordinate schedules. And hopefully, this was helpful. And again, thank you, guys, so much for your continued support. And I’ll talk to you next time. Okay. Bye-bye.

If you need help deciding to treat SIBO, click here.

What do you think? I would like to hear your thoughts or experience with this.


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