Small Intestinal Bacterial Overgrowth & IBS
Irritable bowel syndrome (IBS) is characterized by gastrointestinal distress with hard to explain causes. Small intestinal bacterial overgrowth (SIBO) is characterized by an excessive number of bacteria in the small intestine. Symptoms of SIBO result from bacterial fermentation of carbohydrates and direct damage to intestinal mucosa. The gastrointestinal symptoms of SIBO—including gas, bloating, and abdominal pain—are virtually indistinguishable from those of IBS.
There is mounting evidence that SIBO is associated with and might contribute to the symptoms of IBS. Studies have shown higher frequency of SIBO in patients with IBS than in patients without.
There is mounting evidence that SIBO is associated with and might contribute to the symptoms of IBS. Studies have shown higher frequency of SIBO in patients with IBS than in patients without.
Certain symptoms of IBS are more likely to be associated with SIBO. For example:
- Bloating and flatulence, are symptoms that can be a direct result of carbohydrate fermentation by bacteria present in SIBO.
- Diarrhea is also a symptom that is a common result of the malabsorption associated with SIBO. It has also been shown that SIBO is more common in patients where diarrhea is the predominant symptom of IBS.
It is unclear which came first SIBO or IBS. It is reasonable to assume that the overgrowth of bacteria was the initiating cause of the symptoms of IBS. However, it is equally plausible that the characteristics of IBS, including delayed transit time and disordered motility (which I will discuss more in future posts) may increase a patient’s susceptibility to developing SIBO.
Regardless of which came first, identifying and treating SIBO in patients with IBS can be life changing. You can test for SIBO with a simple and noninvasive test. It can be accomplished with a hydrogen breath test which you can take at the comfort of your home.
Best practice is, therefore, to rule out SIBO if you suspect or have been diagnosed with IBS.
