Pimentel 2011

Evidence unfolding over the past two decades have settled the question: Irritable bowel syndrome, IBS, is, to a great degree, an infectious disease.

Watch TV and you will see frequent commercials for the antibiotic, Xifaxan (rifaximin), to treat IBS. Indeed, evidence from human clinical trials has demonstrated that this antibiotic does indeed provide relief from IBS symptoms for many (as shown in the graph above from Dr. Mark Pimentel’s pioneering publication). Given the general uselessness of other strategies to manage IBS, such as the nonsensical and harmful low-FODMAPs diet or antidepressant medication, an antibiotic strategy represents a step forward. The drug provides partial, occasionally total, relief from bloating, diarrhea, and abdominal pain after two weeks, an effect that endures for at least several months following treatment.

But why would IBS, a condition often labeled “functional,” meaning it is not a real pathological condition but one previously attributed to nervousness, neurotic behavior, or stress, respond to an antibiotic? Easy: because IBS is, in many, if not most cases, really a reflection of fecal microbes that have infested the 24-feet of small intestine, i.e., small intestinal bacterial overgrowth, SIBO. People with IBS show a dramatic increase in Proteobacteria populations of fecal microbes such as E. coli and Klebsiella and depletion of Bifidobacteria and Lactobacilli species in stool samples.  Consistent with a microbial cause for IBS, many people also respond favorably to fecal transplantation.

Studies that ask “What proportion of people with IBS test positive for SIBO?” (usually using breath hydrogen, H2, gas as the indicator, occasionally duodena/jejunal aspirate testing) have yielded varying percentages, depending on the population studied and the method used for testing. An average of 31% of people with IBS have tested positive in around a dozen clinical trials, though as high as 84% in the hands of Dr. Mark Pimentel. As methods to identify the various forms of SIBO improve, I believe that it’s the higher proportion that more accurately reflects the presence of SIBO in IBS. The addition of hydrogen sulfide (H2S) testing, for instance, expands the number of people who test positive for an alternative form of IBS not identified by H2 testing alone.

Think about this for a moment: While it is becoming clear that IBS is a real pathological health condition, it also remains true that emotional stress as an adult or in childhood increases the likelihood of IBS, and that fatigue, anxiety, and depression are common accompanying symptoms, relationships that suggest that some aspect of the so-called “gut-brain axis” is involved. An episode of viral gastroenteritis or food poisoning also increases the likelihood of IBS. It has also become clear that issues beyond the GI microbiome can be at work in IBS, issues such as the immune response driven by an increase in so-called anti-vinculin antibodies that develop in post-infectious IBS. But, for a major proportion of people who suffer from the symptoms of IBS, reducing fecal Proteobacteria and increasing beneficial Lactobacillus, Bifidobacteria, Faecalibacterium, Akkermansia, and others are an effective solution.

My solution, of course, is what I call “SIBO Yogurt,” i.e., a yogurt-like (it’s not yogurt, certainly unlike the stuff you buy in grocery stores) fermented dairy product made by fermenting L. reuteri, L. gasseri, and B. coagulans, chosen for their abilities to colonize the small intestine (or, in the case of B coagulans, germinate in the ileum) and produce bacteriocins, natural antibiotics effective against Proteobacteria. The restoration of L. reuteri and L. gasseri, coupled with consumption of fermented foods, also begins the process of increasing beneficial populations of other microbes, also. To date, the success of SIBO Yogurt has far exceeded my expectations, providing relief to around 90% of those who consume it for a minimum of 4 weeks.

We should also view IBS as a prototype health condition that responds to efforts to address the GI microbiome. Many more health conditions will yield to such efforts including depression, dementia, gout and hyperuricemia, calcium oxalate kidney stones, rosacea, prostate diseases, and numerous others. It is an exciting time that should cause us to reconsider how literally hundreds of diseases are caused and, of course, how they are managed and reversed.

Add it all up: IBS and many other health conditions are really reflections of a disrupted GI microbiome. Effective management should therefore not stop at an antibiotic, an anti-inflammatory drug, an injectable and perversely expensive biologic, nor a surgical procedure. More often then not, the answer lies in informed management of the GI microbiome.