by Amy Castle – Bachelor of Health Science (Naturopathy)


In a conventional medical setting, Irritable Bowel Syndrome (IBS) is a diagnosis of exclusion, meaning that once serious pathologies have been ruled out, a patient who fits the Rome IV criteria (see below) will likely be diagnosed with IBS. As Naturopaths, we are trained to  look beyond this ‘umbrella’ diagnosis, and understand that IBS more often than not has one or several underlying causes that can be elucidated through a thorough case history and the use of functional testing where appropriate. Specific treatment differs according to the individual case and entails one or more of dietary, lifestyle, nutritional & herbal medicine approaches. While it is essential to rule out more serious pathologies eg. Inflammatory Bowel Disease through a GP or specialist in the case of chronic gastrointestinal tract (GIT) issues, the testing utilised is often ineffective at finding the underlying causes of functional GIT issues such as IBS.


Irritable bowel syndrome (IBS) is as a functional gastrointestinal disorder (as opposed to structural or inflammatory) and is estimated to effect 1 in 10 Australians at some point in their lives with a higher prevalence in females. (Boyce et al. 2006) The current diagnostic criteria, The Rome IV (updated in 2016) states that IBS is diagnosed by:


“Recurrent abdominal pain on average at least 1 day a week in the last 3 months associated with two or more of the following:

  1. Related to defecation
  2. Associated with a change in a frequency of stool
  3. Associated with a change in form (consistency) of stool.

Symptoms must have started at least 6 months ago.”(IBS Impact 2016)


IBS  can effect someone’s ability to lead a normal life and cause considerable distress and discomfort, not to mention social isolation in some cases due to a persistent anxiety around the unpredictability of symptoms. Pharmaceutical medications for IBS tend to provide a ‘bandaid’ approach to treatment, doing little to address the underlying cause(s), and may have undesirable side effects especially when used in the long term.


Fructose malabsorption and FODMAP (fermentable oligosaccharides, disaccharides, mono-saccharide & polyols) intolerances are an established cause of some cases of IBS which are assessed with breath testing where possible, and treated with a low FODMAP over a 4-6 week period followed by a slow re introduction of higher FODMAP foods to assess tolerance. (Gibson et al. 2014) While fructose malabsorption and FODMAP intolerances are the cause of IBS for some, there are often other causes, especially in those that have been resistant to these and other treatments.


It is also important to understand that there are often overlapping contributers to GIT symptoms, for example, small intestinal bacterial overgrowth can cause fructose malabsorption, so in this case a low fructose or FODMAP may relieve symptoms but wouldn’t address the underlying cause.



Some potential underlying causes of IBS:

  • Small Intestinal Bacterial Overgrowth – an overgrowth of bacteria in the small intestinal environment leading to a range of GIT symptoms, and non GIT symptoms also. Constipation or diarrhoea predominant or mixed. (Chow, Lin & Pimentel 2003)
  • Large intestinal infections eg. parasites (Alaoui Delbac & Poirier 2012) & bacterial infections. (Grover 2014)
  • Intestinal Dysbiosis – an imbalance of flora in the large intestinal environment, not considered an infection, but can be causative of symptoms. (Major & Spiller 2015)
  • Food sensitivities, including non celiac gluten sensitivity – also known as delayed hypersentivity reactions and distinct from ‘true allergies’ which are mediated by different immune antibodies. (Atkinson et al. 2004)
  • Intestinal permeability – AKA leaky gut. This is often associated with GIT infections, SIBO & food intolerances, so there can be some overlap with other causes here. (Brummer et al 2016)
  • Stress – it is possible that chronic stress is the main underlying cause for some, especially when there has been early life stress exposure – it has been shown that this can disrupt the stress response later in life. Stress can also be a trigger for the development of further GIT imbalances/infections as described above due its negative impact upon immune and digestive function. (Chang 2011)


From a Naturopathic viewpoint, we aim to find the root of a person’s ailments, and then treat accordingly, below are some examples of Functional testing utilised in assessing the underlying causes of IBS:

  • 3 day parasitology stool sample: 3 x stool samples provided on consecutive days (where possible) which assesses the large intestinal environment for the presence of dysbiotic (imbalanced) flora, bacterial infections, yeast overgrowth and parasitic infections.
  • Breath testing using lactulose & glucose to test for the presence for elevated hydrogen and/or methane to assess for SIBO. Testing involves a specific preparation diet followed by administration of lactulose/glucose sugars prior to taking breath samples to assess small intestinal gas levels over a 3 hour period.
  • Assessment of stress/adrenal hormones can be performed with a simple salivary test taken at multiple occasions over one day, or with dried urine samples also taken over one day. Questionnaire based depression & anxiety scales such as the DASS (Depression & Anxiety scales) can be utilised in clinic to assess mood alterations.
  • Stool testing, breath testing and hormone testing can be performed in the comfort of ones home, and always come with detailed instructions to ensure the most accurate test results.
  • Food sensitivity testing can be be performed with a finger blood prick in clinic or a blood draw at a pathology centre depending upon which test is utilised.
  • Food elimination diets involve the removal of commonly offending food groups from the diet for a specified period of time, with a slow re introduction of the removed food items over time utilising food/symptom diaries to assess the potentially offending foods. (It is highly recommended that food elimination testing is done with the support of a qualified healthcare practitioner to ensure the correct approach is taken and to ensure the adequacy of dietary alternatives for nutrient repletion).

Your Naturopath will be guided by a thorough case history to ascertain the most suitable testing based upon your individual signs and symptoms.


Commonly utilised strategies for IBS such as dietary changes eg. low FODMAP diet and probiotic therapy can be helpful in some cases of IBS, but if you have been unresponsive to these therapies, had a worsening of symptoms or have only found minor improvements, consider seeing a Naturopath for further assessment to find the underlying cause, and be provided with a specific treatment strategy.


This article is intended to be informational only and represents the opinion of the author. It is not intended to be used as medical advice and does not take the place of advice from a qualified health care practitioner in a clinical setting. Please check with your healthcare practitioner before embarking upon any of the treatments discussed.

References available upon request.

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