Small Intestinal Bacterial Overgrowth: SIBO and IBS: What’s the Buzz About?

By Sally LaMont, ND, LAc

The latest acronym in the alphabet soup of medicine is SIBO or “Small Intestinal Bacterial Overgrowth”.  SIBO is now considered the leading cause of IBS (Irritable Bowel Syndrome), affecting 1 in 5 Americans. 

Abdominal bloating, gas and cramping, along with intermittent constipation and/or diarrhea are the leading symptoms of IBS. Long considered a “waste basket” diagnosis, patients have been told there’s nothing to do for IBS but take an anti-depressant. While these symptoms can be depressing, there are many contributors to IBS, and the latest one to emerge is SIBO. It was the pioneering work of Los Angeles gastroenterologist, Dr. Mark Pimentel, who first recognized and studied this contributor to IBS.

What exactly is SIBO?
SIBO occurs when the bacteria that normally live in the large intestine, migrate upstream to proliferate in the small intestine. Here, they ferment the starches we eat before we can digest them, causing gas, bloating, heartburn and other symptoms of IBS. But beyond discomfort, these bacteria can damage the delicate small intestinal lining, leading to nutrient malabsorption, intestinal hyper-permeability (“leaky gut”), and altered motility.  

What causes SIBO?
There are many causes of SIBO, but it is often a case of severe food poisoning that trips the trigger. Bacteria like E. coli, Salmonella and others, secrete toxins that damage the “migrating motor complex”. The MMC is a set of automatic cleansing waves that sweep the digestive tract from the top down during times of rest (between meals and at night). If this is damaged, it allows bacteria to move upstream. Overuse of acid-blockers, antibiotics, opiates and other drugs also contribute. Altered anatomy of the intestinal tract, through surgery, adhesions, endometriosis or diverticulitis, can also create areas where bacteria can be trapped and overgrow to cause SIBO.

How is SIBO diagnosed?
When excess bacteria are living in the small intestine, they digest the starches we eat, and in doing so, generate gasses that can be captured through a simple and inexpensive breath test at home. The tubes are then sent to the lab and results graphed out.  If there is a rise in either or both hydrogen or methane gas, then SIBO is suspected. At MNMC, we use Aerodiagnostic Labs, which provides state-of-the-art technology to ensure the highest level of accuracy in diagnosing SIBO. It is important to be tested before treating, as there are other contributors to IBS that may need to be addressed to ensure complete resolution.

How is SIBO treated?
Two different protocols have been proven to eradicate SIBO (though it may take more than one course of either). The first employs a special antibiotic that is active only in the small intestine; is not absorbed systemically nor does it kill the good bacteria in the large intestine. The other is a botanical protocol that was developed by our colleagues at the naturopathic medical school in Portland, and studied by a gastroenterologist at Johns Hopkins, which demonstrated a very similar remission rate.  

The best success in eradicating SIBO and resolving IBS depends on accurate diagnosis, and pairing the right antimicrobial treatment with the right diet.  At Marin Natural Medicine, I’m experienced in using a range of low fermentable carbohydrate diets, both antibiotic and botanical treatment protocols and will help you determine the most effective protocol for your personal situation.  I look forward to working with you to improve your digestion and start feeling great again!