Small intestinal bacterial overgrowth, or commonly known as SIBO, is when there is an overgrowth of bacteria in the small intestine, as usually the small intestine only houses a small number of bacteria (1). This can lead to symptoms like bloating, abdominal pain and diarrhoea (1).

1. Causes & Risk Factors

There’s not one known cause for SIBO, and it seems to be something that’s multifactorial. Some research cite causes such as an impairment of the ileocecal valve, slower small bowel motility, and higher gastric acid secretion (2). Long-term use of protein pump inhibitors medications, used to treat reflux, is considered another risk factor (3).

2. Diagnosis

SIBO can be diagnosed by sampling fluid from the small intestine and testing it for bacteria. Although this is the most accurate test, it is also very invasive (1). Breath testing is an alternative test that is non-invasive and now popular in clinical practice (1). However, the breath tests may lack sensitivity and specificity, meaning that there is a chance of getting a false positive or negative result (1).

3. Treatment Options

The most studies antibiotic for SIBO is rifaximin, a drug that works primarily in the gut (1). Probiotic formulations have also been studied as a treatment for SIBO, as well as anti-microbial agents. New research is showing adjunct treatment with antibiotics, probiotics and nutrtional management are showing promising results.

4. Nutritional Management

Nutrition interventions are successful at reducing SIBO symptoms and preventing reoccurrence. Diets suited to those with SIBO are low FODMAP, the specific carbohydrate diet (SCD) and the bi-phasic diet. All of these options reduce the fibres that ferment in the gut and can exacerbate symptoms, as well as ‘starve out’ excess bacteria that may take up residence in the small intestine (1).

References

(1) Monash University. (2017). What’s the go with SIBO? http://www.monashfodmap.com/blog/whats-go-with-sibo/

(2) Roland, B. C., Ciarleglio, M. M., Clarke, J. O., Semler, J. R., Tomakin, E., Mullin, G. E., & Pasricha, P. J. (2014). Low Ileocecal Valve Pressure Is Significantly Associated with Small Intestinal Bacterial Overgrowth (SIBO). Digestive Diseases and Sciences, 59(6), 1269–1277. https://doi.org/10.1007/s10620-014-3166-7

(3) Compare, D., Pica, L., Rocco, A., De Giorgi, F., Cuomo, R., Sarnelli, G., Romano, M., & Nardone, G. (2011). Effects of long-term PPI treatment on producing bowel symptoms and SIBO. European Journal of Clinical Investigation, 41(4), 380–386. https://doi.org/10.1111/j.1365-2362.2010.02419.x