SIBO Update 2015: Pt. 1


Disclaimer: As I have said in the past, I’m not a research blogger. I’m here to mix “data with soul” and give you useful info, but only in the context of my real, human experience. That is not to say that citation on my part and proper follow-up on your part are not important. Everything I wrote about in this blog was presented by Dr. Mark Pimentel at the SIBO Symposium during June 2015 and you can pay to have access to those presentations through the National College of Natural Medicine’s website.

If you’d like to read my original SIBO series, starting with the 2014 Symposium, you can start here.

Readers!! Holy Moly! The SIBO Symposium this year was Amazing with a capital A. It is taking me time to carefully work my way through each presentation, taking notes and reviewing the materials from each speaker, but once again I am blown away by the incredibly valuable information. Those of us who have dealt with or are dealing with SIBO (small intestine bacterial overgrowth) are so lucky to have such a fantastic group of medical and naturopathic experts joining forces to bring this information to the healthcare field and general public.

The presentation I am writing about for this first update to my SIBO series was done by Dr. Mark Pimentel from Cedars-Sinai Medical Center in Los Angeles. Dr. Pimentel is one of the leading SIBO researchers and what he brought to the Symposium this year was huge. Before I dig into that though, there is a breakthrough that needs to be shouted from the mountaintops. The US Food and Drug Administration (FDA) has finally approved Rifaximin for treatment of irritable bowel syndrome (IBS)!! This decision could soon affect the policies of so many insurance providers who currently do not cover Rifaximin, a prohibitively expensive antibiotic, for SIBO patients.

You may notice some wording there that needs clarification. Are IBS and SIBO the same thing? Not all IBS is SIBO, but at least 60% of IBS patients do have bacterial overgrowth as the underlying cause of their symptoms. So, yes, it would seem an approval for treating IBS with Rifaximin is a win for SIBO folks, since they fall into this IBS with overgrowth category. (I’m going to use the IBS acronym, like Dr. Pimentel did in this post for accuracy, but since I am writing for that 60% SIBO crowd you’ll know that’s the group I’m referring to here.)

Okay, on to Pimentel’s research . . . so one of the first things he presented was work dispelling the idea that stress causes IBS. He pointed out that patients suffering with a disease long-term and seeking help repeatedly are likely to present with a detectably high-level of anxiety, but that does not mean the stress they are experiencing caused the disease. This was proven by conducting research with the military in which troops who had experienced the highest levels of stress (using a weapon in combat, killing another human in combat, being injured in combat) were followed to see if they developed IBS. It was not a predictor for developing IBS. However, troops who got food poisoning very often did develop IBS. Next they compared patients with IBS to patients who had more severe diseases of the digestive system (like Ulcerative Colitis) and it was found that the UC patients had higher levels of depression and anxiety. All of this supported the idea that stress does not cause IBS, but dealing with chronic illness does cause stress. Can that stress worsen symptoms? Yes, but again, it is not the cause of the disease.

Pimentel went on to say that breath testing was not taken seriously enough early enough with IBS, since it really required shifting the field from believing IBS was a psychological disorder to thinking it is a microbiological disorder. I think Pimentel’s thrust with all of the research on stress and breath testing was that we are finally moving firmly away from blaming the patient and into seeing IBS as a true disease.

In the second half of Pimentel’s presentation, he began to talk about how food poisoning, IBS, and SIBO are linked. This part of the presentation was crazy!! I had to re-watch and re-take notes twice to make sure I was taking it all in. I hope I do it justice here.

Basically, through eight years of research, they were able to show that through an autoimmune process, infection by certain types of bacteria could lead to developing SIBO. Here’s how it works:

  1. The researchers found that four bacterial strains that are proven to cause IBS, campylobacter jejuni, e.coli, salmonella, and shigella, all have a toxin called Cytolethal Distending Toxin (CDT) in common. This toxin causes the nerve cells responsible for the migrating motor complex (MMC, the automatic cleansing wave action of the intestine) to slow down.
  2. This slowing happens through an autoimmune process, where you first form antibodies to the toxin (anti-CDT antibodies), but they also begin damaging a protein, vinculin, that looks similar on the nerve cells (anti-vinculin antibodies).
  3. With the nerve cells now damaged, the MMC slows down, so that bacteria is no longer swept out of your small intestine into your colon as efficiently as before. This allows bacteria to have time to feed (on your food), reproduce, and overgrow in the small intestine, where they do not belong; producing gases that make you feel lousy. Wa-lah! SIBO!

To make matters worse, if you are exposed to these bacteria again, it takes less (smaller numbers) of that bacteria to make you sick, because your gut is so slow they have plenty of time to overgrow. This means you are more likely to get sick from these exposures in the future than others.

Antibody testing is important for many reasons. First, it means doctors can distinguish IBS from IBD, but still validate IBS as a real disease and help patients have confidence that symptoms are not “all in their head.” Additionally, the higher the antibody count, the worse the SIBO, which can alert a doctor to how difficult a case may be to treat. The presence of the antibodies also demonstrates the importance of prokinetics (pro-movement drugs) in the treatment of SIBO that was caused by exposure to CDT toxin, since this toxin has already slowed the intestine. Finally, it can help the patient make informed choices about future travel to regions where exposure to these bacteria through food is very likely; since they know they are now more susceptible. Antibody testing will not cancel breath testing though, as the results (hydrogen or methane) are essential for informing doctors on the right treatment course.

I think it is important to note again that not all cases of IBS are SIBO. And not all SIBO is caused by CDT toxin exposure (some cases are related to bowel irregularities, for example).

What do you think readers? Is this major stuff or what? Does it help you draw any connections in your SIBO journey? Maybe that food poisoning you got on that trip to Peru, for instance??

You can read Part 2 of this update series here, Part 3 here, or start with the original series here.

About Angie Alt

Angie Alt is a co-founder here at Autoimmune Wellness. She helps others take charge of their health the same way she took charge of her own after suffering with celiac disease, endometriosis, and lichen sclerosis; one nutritious step at a time. Her special focus is on mixing “data with soul” by looking at the honest heart of the autoimmune journey (which sometimes includes curse words). She is a Certified Health Coach through the Institute for Integrative Nutrition, Nutritional Therapy Consultant through The Nutritional Therapy Association and author of The Alternative Autoimmune Cookbook: Eating for All Phases of the Paleo Autoimmune Protocol and The Autoimmune Wellness Handbook. You can also find her on Instagram.


  • Betül Tatar says

    IBS is not in my head? WHAT?! Lol… I have a long list of physicians I have to share this with! Thanks for the post, Angie. So informative as always!

    • Angie Alt says

      You are welcome Betul!! These guys are geniuses, right!? More coming soon!

  • Holly says

    Thank you for posting this valuable information! I wonder, what antibody test do I request from my gastroenterologist? Is there a name? He never mentioned such a test before. Also, do you feel AIP is the best course of action with SIBO? I seem to have trouble digesting starches and I know they are allowed on AIP.

    • Angie Alt says

      Holly, I’m not sure what exactly the title of the test is, my assumption is CDT antibody?? Hopefully as I make my way through the Symposium materials that will be clarified. Also, I’m not sure how widely available the testing is yet. I have seen people mentioning that they had the testing done w/ Dr. Pimentel, but I’m not sure that is outside his clinic yet. If you have autoimmune disease in addition to SIBO, I think AIP+Low-FODMAP is the a great path for dealing w/ SIBO in addition to treatment. If starches are an issue, you may want to experiment further, perhaps trying SCD as recommended by Dr. Alison Siebecker.

  • Thank you Angie for the fantastic information. This adds to the SIBO puzzle! I look forward to the next part of your summary from the SIBO symposium.

    • Angie Alt says

      Glad it was helpful Catherine!! Thanks for reading!

  • Jess says

    Oh my gosh! This could not have been posted at a better time. I actually just stumbled upon your page looking for “autoimmune paleo” recipes as it appears that is the direction my diet is headed and saw this post in the meantime. I have Hashimoto’s, but my naturopath also just diagnosed me with SIBO just today. I wonder if I should have the CDT antibodies test. Anyway, sorry for the ramble. Thank you for sharing this information and thank you in general for sharing your health journey.

    • Angie Alt says

      Hi Jess! Glad you found the post informative. To be very honest, I’m not sure how widely available the antibody testing is at this time. I have seen people mention that they got it down in Dr. Pimentel’s clinic, but I don’t know if it available beyond there yet. Worth asking your ND about though.

  • Davaun says

    Yes! Wow
    I did extensive world travel in 2011, getting terrible food poisoning, & ever since I’ve had extreme SIBO symptoms that won’t go away.
    I’ve always thought there was a connection, but now what can I do?
    Thank you!

    • Angie Alt says

      Hi Davaun! Next step is finding a doc & get tested for SIBO, then start the treatment process. Glad this helped connect some pieces for you.

  • These SIBO articles are wonderful! I had an interesting pregnancy (no appetite or food cravings but threw up bile almost every morning the first half lost a lot of weight and had really severe hives) all of my fungal symptoms had seemed in remission though and I barely felt the effects of my severe Florida allergies. Then I got food poisoning at the end of my pregnancy and everything changed. My child was born with severe gas which probiotics don’t help. I am nursing him and gained a pound a week the first 6 months of his life until I made the gut-grains connection and have brought the rapid gain and overindulgence to a standstill. i have recently been diagnosed Through breath tests I confirmed that the loose -run as-fast-as-you-can SIBO I have is hydrogen producing and a stool panel found imbalance of micro flora, yeast (but a different kind than candida) and elevated E. coli. and now my doctor is ready to do every scopy there is on me which makes me so nervous! My journey to wellness begins! I can’t thank you enough for informing me about lactobacillus and cartilage in bone broth!! That is MAJOR information right there! I’m excited to start exploring low FODMAP SCD for myself and my baby!

    • Angie Alt says

      Thanks so much for reading Punk Rock Herbalist! Best of luck on your journey!

  • Patrik says

    Very nice summary.
    I believe the test is actually just called the IBS breath test.
    /. Patrik

    • Angie Alt says

      Hi Patrik! Thanks for reading. The breath test is different from the blood test.

  • […] can read Part 1 of this update series here, Part 3 here, or start with the original series […]

  • […] can read Part 1 of this update series here, Part 2 here, or start with the original series […]

  • Iatrogenia says

    Angie, is this the paper Dr. Pimentel was referring to:

    Pimentel M, Morales W, Rezaie A, et al. Development and Validation of a Biomarker for Diarrhea-Predominant Irritable Bowel Syndrome in Human Subjects. Ro S, ed. PLoS ONE. 2015;10(5):e0126438. doi:10.1371/journal.pone.0126438.

    It is about a specific type of chronic diarrhea, not all SIBO.

  • Susie says

    Hi Angie,

    I have been diagnosed with SIBO and am doing a protocol prescribed by my doctor;
    Low Fodmap/ SCD diet from Dr. Seibecker and CandiBactin AR/BR, Interface Plus &
    Prescript Assist. We decided against the Rimafaxin due expense and to my low
    Biodiversity of good flora from treating Hpylori.
    I will read all of your SIBO articles and appreciate your hard work (and occasional
    swear words). Venting feels good!

    Can you recommend good cookbook resources for SIBO? I am guessing this is
    a lifetime adventure in food limitations.
    Thanks! Susie

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