SIBO (Small Intestine Bacterial Overgrowth) is a condition in which bacteria that should be in the large intestine begin to congregate in the small intestine in far higher numbers than normal. This happens when the migrating motor complex (MMC) fails to effectively sweep bacteria in the small intestine back into the large intestine between meals. Once in the small intestine, these bacteria multiply and feed off carbohydrates from food, creating gases, specifically methane and hydrogen. These gases are responsible for the SIBO symptoms which include abdominal pain, bloating, flatulence, constipation and diarrhoea.
It is now thought that SIBO may be the underlying cause in many cases of IBS as well as one cause of intolerances to sucrose, fructose and lactose. Overgrowths of bacteria in the small intestine can also lead to malabsorption, pale fatty stools and anaemia.
But SIBO can affect much more than just digestion and absorption. It is also associated with:
- Chronic pancreatitis
- Acid Reflux
- Acne rosacea
- Skin Rashes
- Restless legs
- Joint pain
- Weight loss or gain
- Food sensitivities
- Interstitial cystitis
- Rheumatoid arthritis
- Chronic Fatigue Syndrome
The only way to currently diagnose SIBO is by taking a SIBO breath test. The test works by measuring the production of hydrogen or methane gas after the ingestion of glucose or lactulose. If there is an overgrowth of bacteria in the small intestine, large quantities of fermentation gases will be produced and can be detected in a breath sample.
The lactulose test is most useful for diagnosing bacterial overgrowth in the end of the small intestine. This is commonly associated with constipation dominant IBS. <insert link>
The glucose test is most effective for assessing bacterial overgrowth in the upper part of the small intestine. This is typically present in cases of diarrhoea dominant IBS <insert link>
A SIBO test is recommended to those who:
- Suffer from IBS, especially if there is a lot of abdominal bloating and gas
- Have one of the conditions above that may be aggravated by SIBO
- Have unexplained digestive symptoms as well as vague symptoms such as fatigue, headaches and joint pains