A critical appraisal of the SIBO hypothesis
Absolutely loving this new paper by Dr. Purna Kashyap and colleagues!!
Years ago, I argued against the entire premise of small intestinal bacterial overgrowth (SIBO), questioning its reliance on outdated culture-based methods and unreliable breath tests for diagnosis. I suggested, along with a few researchers at the time, that irritable bowel syndrome (IBS) was likely characterized by dysbiosis.
In 2019, Dr. Kashyap’s lab published a study confirming that indeed, small intestinal dysbiosis, rather than bacterial overgrowth, underlies most functional GI disorders (I wrote about it on my blog here).
Now, this 2024 review paper critically appraises the literature to date and offers updated clinical practice guidelines, endorsed by BOTH the European and American societies of Neurogastroenterology and Motility.
Here are some of the key points and excerpts from the paper:
Breath testing for SIBO is innacurate and should be abandoned:
“This narrative review outlines compelling evidence that breath testing to diagnose SIBO in patients with IBS and related disorders is inaccurate and should be abandoned as a diagnostic test for this purpose.”
SIBO diagnosis can have harmful consequences:
“…the high number of false positive tests and results which have no clinical foundation can have harmful consequences for our patients. Most importantly, it leads to a SIBO diagnosis for which evidence is lacking, often creating confusion, anxiety and potential loss of trust in the healthcare system. The practical consequences of a positive tests include that it typically leads to one or more courses of potentially harmful antibiotics.”
We need to view the gut as a complex system (and focus on the gut environment):
“This review […] does not refute that small and large bowel microbiota could generate IBS-like symptoms in some patients. Rather, it highlights the importance of focusing on the complexities of communities of bacteria and their constant metabolic response to the host, especially in response to diet and related digestive factors such as gastric acid and bile salts, and not just simply measuring absolute numbers of bacteria.”
Overall, this review provides a much needed formal challenge to conventional approaches to diagnosing and managing functional GI disorders. I’m hopeful that this information will be shared widely among functional and integrative practitioners, and these updated guidelines given more consideration in clinical practice. Many well-meaning practitioners have relied on breath testing for SIBO to justify aggressive antimicrobial treatments and restrictive diets, often overlooking the profound impact of lifestyle factors, the nervous system, and stress management on gut health and overall well-being. I plan to explore these latter themes more in future posts.
Yup. I've been saying this since 2017 when a naturopath destroyed my gut microbiome and gave me leaky gut after saying I needed to be treated for "borderline" SIBO according to a breath test. I didn't think it was necessary since it was likely just dysbiosis from antibiotic usage, but she vehemently disagreed. So, I did the month-long naturopathic protocol and completely destroyed my gut and my health. I've never regretted anything more in my life.
Thanks Lucy for sharing. I've almost moved completely away from doing breath testing now to metagenomic testing for clients along with using clinical diagnostic skills. Also, I'd like to add that a lot of my naturopathic colleagues - here in Australia at least - are quite cautious about the use of antimicrobials. People like Jason Hawrelak and Brad Leech are really vocal about using selective antimicrobials as much as possible, avoiding ones such as oregano oil and extended use of berberine. I know some of this knowledge has slowly filtered through to other countries but we all need to keep sharing and raising awareness to speed this process. For what it's worth, my clients with seriously damaged guts have arrived at this as a consequence of rx antibiotics like Flagyl and triple therapy or year-long use of prescribed antibiotics from supposed experts at clinics like the CDD here in Sydney. I've had a few clients who are exquisitely sensitive to both pharma and herbal antimicrobials, so your work to explain "oxygen dysbiosis" has been incredibly helpful to forge a new path for treatment for these tough dysbiosis cases.