SIBO and the Role of the Low FODMAP Diet

SIBO and the Role of the Low FODMAP Diet

Written by Lisa Kunstler, FodShop Nutritionist and Group Fitness Instructor

What is SIBO?

In normal human health, there are millions of bacteria, all controlled by normal gastrointestinal defense mechanisms. (1) Small intestinal bacterial overgrowth (SIBO) is defined as an increased amount of bacteria and/or a change in bacteria in the gut, resulting in nutrient malabsorption. (1)  Symptoms can include bloating, diarrhoea, abdominal pain, nausea, weight loss and nutrient deficiencies. (1)


Causes of SIBO 

There are a number of different causes for SIBO that lead to competition between the gut cells and bacteria for nutrient absorption, which can lead to a release of toxins that injure the intestinal cells. Some people may only have SIBO however, most have an underlying disorder causing SIBO. (1)


Old age

Major risk factors that are common with older age include small bowel diverticulosis, decreased gastrointestinal movements, prior gastrointestinal surgery, or achlorhydria. (1)


Diabetes mellitus

SIBO is a common complication associated with diabetes, especially those with neuropathy and delayed gastric emptying. (1)


Irritable bowel syndrome (IBS)

There is massive overlap between IBS and SIBO for many reasons. Sometimes SIBO can cause IBS to develop or IBS can cause SIBO due to dysfunction in the gut. Some theorise that they are entirely different entities with no overlap. Some studies have shown SIBO to be more prevalent in IBS-C compared to IBS-D patients. (1)


Coeliac disease

Those with coeliac disease who's symptoms are continuous despite following a gluten free diet may have SIBO. This is caused by the inflammation in the small intestine that can induce bacterial growth.  (1)


Other diseases and disorders

There have been other connections to SIBO through other diseases and disorders including Crohn's disease and short bowel syndrome. (1)


Diagnosis of SIBO

Diagnosis is difficult and therefore, it is currently unknown how much of the general population have the condition. It is significantly undiagnosed due to symptoms being confused with other functional bowel diseases and asymptomatic individuals. (1)

The most common diagnosis for SIBO is through hydrogen breath testing because it is the most non-invasive, cheap, simple, and safe test available. (2) A liquid of glucose and lactulose is taken orally and then the test determines the amount of hydrogen in the breath, produced by the bacteria in the gut as a consequence of carbohydrate fermentation of glucose and lactulose. The increase of hydrogen in the breath compared to before liquid ingestion can diagnose SIBO. (2)

However, whilst this is the current method on the market for SIBO diagnosis, it has its concerns for reliability. Hydrogen breath testing has poor reproducibility and little ability to predict symptom response. (3) There is even some evidence to say results may be influenced by the patient's physiology at the time, including feelings of anxiety. (3)


Management of SIBO

First line therapy for SIBO is a a course of antibiotics, as well as treating the underlying cause. (1) On top of this, probiotics, herbal therapies, and certain diets can significantly alleviate the symptoms of SIBO. 

A low FODMAP diet can be used to treat SIBO considering that carbohydrates are the main source for bacteria to thrive. (1) The diet minimises the consumption of fermented, short chain carbohydrates, which are not easily digestible and end up being fermented by the gut bacteria. This can significantly reduce symptoms in SIBO patients. (1)

Additionally, probiotics can help by altering the bacteria in the gut. They strengthen the gut's barrier function to change the inflammatory response and decrease hypersensitivity. (1)

As SIBO can cause malabsorption in patients, especially in vitamin A, B12, D and E, these should be regularly consumed or supplemented in the diet. (1) When nutrients are hard to get in, sometimes looking to get a meal replacement product that is easily and rapidly digestible can help. 

Element Gold is a nutritionally complete meal that is low FODMAP and has pre-digested proteins that can be broken up into individual subunits called amino acids, making them easier to digest and access in the gut. To understand more about Element Gold, click HERE


Final Thoughts

SIBO is caused by an overgrowth of bacteria in the gut, which can impact nutrient absorption and cause symptoms like abdominal pain, constipation, and bloating. There are various causes for SIBO and many people remain undiagnosed due to the issues surrounding hydrogen breath testing as a SIBO diagnosis tool. Management of SIBO can be treated with antibiotics and a low FODMAP diet to prevent nutritional deficiencies and troublesome gut symptoms. Additionally, meal replacements, like Element Gold, can be good options for those who struggle to consume their recommended daily nutrient intake. 




1. Salem, Ahmed & Roland, Bani. (2014). Small Intestinal Bacterial Overgrowth (SIBO). Journal of Gastrointestinal & Digestive System. 4. 225. 10.4172/2161-069X.1000225.

2. Gabrielli, M., D'Angelo, G., Di Rienzo, T., Scarpellini, E., & Ojetti, V. (2013). Diagnosis of small intestinal bacterial overgrowth in the clinical practice. European review for medical and pharmacological sciences17 Suppl 2, 30–35.

3. Yao, C. K., Tuck, C. J., Barrett, J. S., Canale, K. E., Philpott, H. L., & Gibson, P. R. (2017). Poor reproducibility of breath hydrogen testing: Implications for its application in functional bowel disorders. United European gastroenterology journal5(2), 284–292.


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