Small Intestinal Bacterial Overgrowth (SIBO)

What is Small Intestinal Bacterial Overgrowth (SIBO)?

Small Intestinal Bacterial Overgrowth (SIBO) refers to an overgrowth of bacteria in the gut, predominantly in the small intestines. The microbiota is essential for health and life, so having bacteria in the gut is normal. However, an imbalance can cause problems. 


SIBO can lead to symptoms similar to irritable bowel syndrome or IBS symptoms, namely diarrhoea, flatulence, constipation, bloating, and distention. The symptoms present depend on the kind of bacteria going rampant in the small intestine.


It is important to see a doctor and get the correct diagnosis, to determine if SIBO is truly the cause for one’s symptoms. Many of the symptoms of SIBO can be caused by other conditions, so the doctor would need to examine you and may perform some tests to ascertain if SIBO is the root cause.


The cause of SIBO usually lies in a movement problem in the small intestine. Your small bowel initiates a peristaltic wave regularly, which sweeps through the small bowel and dumps everything like residual food, bowel secretions, digestive enzymes and excessive amounts of bacteria. If something impairs the wave, the small intestine is unable to expel the bacteria. Similar to a stagnant pool, the small intestine becomes an ideal environment for pathogenic bacteria to thrive and reproduce.


Risk factors for SIBO include nerve damage in the gut resulting from diabetes, diverticulitis of the small intestine, any bowel obstruction and multiple courses of antibiotics. SIBO can also be the outcome of conditions that reduce naturally occurring stomach acid which is also bacteria-killing – these would include gastric diversion surgery and long term use of acid suppressing drugs such as proton pump inhibitors. SIBO can also result from a prolonged gut infection; if it lasts beyond two weeks, any lingering gastrointestinal issues could be SIBO-related.


Diagnosis of SIBO is done using a breath test that measures how much hydrogen or methane gas ends up in your breath. These gases are both by-products of bacteria breaking down sugar in your gut, which then enters the bloodstream and is released into the alveoli, where it is then exhaled and collected using our diagnostic test kit. There are no blood or stool tests for SIBO.


If the breath test indicates SIBO, your doctor will investigate and address any underlying issue that may cause the problem. Clearing up the overgrowth usually requires special non-absorbable antibiotics, to be determined by your doctor depending on whether it is hydrogen or methane predominant. However, recurrences are common thus you may need to repeat courses of the medication.

Whilst scientific evidence is lacking, some people try home remedies. Herbal supplements and gut-healing herbs can also be used to treat or kill off gut bacteria overgrowth, and dietitians may advise on a SIBO diet.