What is SIBO?

Small Intestine Bacterial Overgrowth (also known as SIBO) is more common that originally thought and can have a significant impact on one’s quality of life. It is more likely to affect females, older adults, and those with gastrointestinal issues like irritable bowel syndrome (IBS). SIBO occurs when there is an unusually large population of bacteria in the small intestine.

This imbalance of bacteria is often a complication of other digestive disorders.



What are the Causes of SIBO?


Bacterial overgrowth occurs either when bacteria from one part of the digestive tract travels to the small intestine OR when naturally occurring bacteria in the small intestine multiply too much.

This can happen due to low levels of stomach acid, the abnormally slow movement of the digestive system, small intestine physical abnormalities, a weakened immune system or following a bout of viral gastroenteritis.


What are the Risk Factors of SIBO?


Certain medical conditions are associated with SIBO, including Irritable Bowel Syndrome (IBS), Crohn’s disease, Coeliac disease, cirrhosis of the liver, hypothyroidism, HIV, diabetes, schleroderma and fibromyalgia.

Other risk factors include older, age, being female, long term use of proton pump inhibitors (PPIs), previous bowel surgery, recent antibiotic use and alcohol consumption.



What are the symptoms of SIBO?


The symptoms of this condition are very similar to those of other gastrointestinal disorders, like IBS and lactose intolerance. These symptoms can vary in severity and also between individuals and directly affect the gut.

Symptoms include abdominal pain (especially following a meal), bloating, diarrhoea, nausea and unintentional weight loss.

SIBO can make it difficult for the body to absorb fats and carbohydrates from food. This can lead to vitamin deficiencies and excess gas. Other complications include malnutrition, dehydration and leaky gut (a term used by naturopaths for an imbalance in the gut)



How is SIBO diagnosed?


Due to the range of symptoms, the varying degrees of severity and the fact that the symptoms are so similar to those experienced with other gastrointestinal conditions, SIBO is not easily diagnosed.

Your doctor will review your medical history, have a discussion about your symptoms and if they suspect bacterial overgrowth, they will request that you have a breath test.

Bacteria produce hydrogen and methane when they break down carbohydrates in the gut. This test measures the concentration of hydrogen and methane in one’s breath which provides information about the severity and location of the bacterial overgrowth in the gut.

The test is non invasive and you’ll be required to fast overnight.


How is SIBO treated?


Treat any underlying conditions, such as Coeliac disease or diabetes as these contribute to SIBO.


Make dietary changes as these can help in relieving symptoms. There isn’t enough concrete evidence to suggest which diet is best, however there are dietary guidelines that can help relieve symptoms. Given that gut bacteria feeds on carbohydrates, SIBO diets work on limiting carbohydrate intake to prevent bacteria from growing. People can also benefit from a diet low in FODMAPs.


Occasionally antibiotic therapy is used when dietary changes are not effective. Broad-spectrum antibiotics help stabilise the gut microbiota by reducing the number of intestinal bacteria.


Probiotics are often mentioned when SIBO is discussed, however, there is not enough concrete evidence to support its use over antibiotics.


If you think you may have SIBO, please see your doctor.


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