When a patient is diagnosed with small intestinal bacterial overgrowth (SIBO), they often breathe a sigh of relief! Finally, the doctor has found what is wrong with me! In reality, the detective work has just begun.
SIBO is a condition in which microbes overgrow in the small intestine. We have many microbes living in our intestines but most reside in our colon (large intestine). Normally, the small intestinal environment should not be suitable for the survival of an overgrowth of these bugs.
The prevalence of SIBO in the general population is unknown. Research studies reveal anywhere from 0-20% of healthy individuals have SIBO. For those with irritable bowel syndrome, incidence of SIBO ranges widely from 4-64% or even higher depending on testing methods and testing criteria. This wide range in prevalence reveals the conundrum that SIBO presents; there is no gold standard to define or diagnose SIBO. Glucose and lactulose breath testing are most commonly used in the clinical setting but interpretation varies from institution to institution.
Before I get started on my thoughts about SIBO, let me state clearly, that this is an area that has been researched, but much more work has to be done. We need more studies to better understand the potential role of diet, probiotics, medications, food borne illness and their relationship with the onset and treatment of SIBO. I am providing my musings based on research I have read in the medical literature, discussions with researchers, personal experience (I unfortunately have had SIBO), and professional experience as a registered dietitian– about 65% of my patients have been diagnosed with this condition.
Although, it is possible that you may never determine how and why you developed SIBO, it is important to attempt to uncover the reason your developed an overgrowth of bacteria in your small intestine. SIBO has a good chance of re-occurring if you don’t find the root cause. Sometimes the cause is modifiable, to decrease rate of relapse –sometimes it is not.
Here are my thoughts:
Step #1: Attempt to uncover possible risk factors for the development of SIBO. SIBO is a symptom per se, something changed the environment or function in the small intestine to allow microbes to overgrow. The medical team and the patient should work together to identify possible causes. The patient’s job is to provide an accurate account about the onset of symptoms to the doctor. The doctor assimilates this information along with testing and a physical exam to create the most viable potential causes. The dietitian tends to have a greater duration of time with the patient and is often a valuable player in helping piece the history together. This is just one reason why it is essential that medical professionals collaborate to provide the best care for the patient. As a patient, encourage your health team to work collaboratively.
Some potential causes of SIBO: Infection (such as food borne illness), untreated celiac disease, poor motility in the intestine linked with IBS or previous abdominal surgeries, GERD (gastro-esophageal reflux) treated with proton pump inhibitors (PPI) medication, chronic pancreatitis, hypothyroidism or diabetes, to name a few. What changed the small intestinal environment? What changed the small intestine motility?
Step #2: Is the potential cause treatable? If so, then treat. For instance, if you can treat the new celiac patient with a nourishing gluten free diet and treat the SIBO with suitable antibiotics, that patient might be all set. If you can lower the PPI dose or change from a PPI to an H2 Blocker, to treat heartburn or reflux, the small bowel pH (the amount of acid in the small bowel) might be less altered. Less acid in the small intestine may allow bacteria to overgrow. For example, the doctor might try try Pepcid (H2 blocker) versus Nexium (PPI) to manage the GERD symptoms. Perhaps this change in medication, will minimize the impact on the acid conditions in the small intestinal environment enough—so SIBO doesn’t relapse. Severe constipation or incomplete emptying of the colon, can impact small intestinal motility, a potential risk factor for SIBO too. If a SIBO patient presents with ongoing constipation—perhaps initiate a bowel regimen and check for pelvic floor dyssynergia. If a patient developed SIBO after a bout with food poisoning——(common food borne pathogens can lead to partial small bowel paralysis)—perhaps patients might benefit or low dose erythromycin at night (50 milligrams dose) to stimulate small bowel cleansing. Additionally, spacing meals out 3-4 hours vs. grazing will allow the migrating motor complex (MMC)–the housekeeper of the small intestine– to initiate a cleansing wave to cleanse the small bowel of food and bacteria. The MMC only occurs in the fasting state.
I understand from a patient’s perspective that having numerous tests come back negative can feel defeating, in a way. No one wants to be diagnosed with a life threatening illness, that is for sure. But, when illness, takes your quality of life away, it can be daunting. When small intestinal bacterial overgrowth testing proves to be positive, patients often rejoice. Just remember, the detective work has just begun.
For more about SIBO, consider reading my long winded post here. For dietitians in practice, you can purchase my patient ready SIBO handout ($10) to use with your patients, if you’d like. The SIBO handout can be found here.