Tag Archives: diarrhea

SIBO (Small Intestine Bacterial Overgrowth) Breath Test

Is the SIBO breath test the right laboratory test for you?

In our experience, many persons having digestive symptoms receive a diagnosis of irritable bowel syndrome (IBS), but no particular guidance in identifying possible causes, or options for treatment other than symptom management (e.g., laxatives). SIBO (Small Intestinal Bacterial Overgrowth) breath testing may be the first step to understanding your digestive symptoms, and taking action at the “root cause” level.

Although this test is commonly referred to as SIBO breath testing, it may also be used to diagnose carbohydrate (sugar) malabsorption.

This laboratory test is used primarily to identify possible causes of:

  1. Unexplained irritable bowel syndrome (IBS) symptoms1 (abdominal pain, bloating, gas; diarrhea and/or constipation; mucous in stool2)
  2. Unexplained abdominal bloating3

Other health conditions associated with SIBO include:

  • Weight loss1
  • Anemia1
  • Malnutrition1
  • Hypothyroidism
  • Fibromyalgia1
  • Parkinson’s disease1

Specifically, this test diagnoses:

  1. Overgrowth of bacteria in the small intestine, or migration of bacteria from the large intestine to the small intestine3

  2. Carbohydrate (sugar) malabsorption3

How does SIBO breath testing work?

Breath testing relies on measurement of gases produced in the intestines that diffuse into the bloodstream and are ultimately expired through the lungs.3

Two of the main gases found in the breath, and produced exclusively by microbial fermentation of carbohydrates, are hydrogen and methane.3

Excess hydrogen and/or methane will be produced if excessive gut bacteria cause excessive fermentation of carbohydrates, either:

  1. In the small intestine because of small intestine bacterial overgrowth (SIBO)4, or
  2. Malabsorption of carbohydrates in the small intestine, allowing excessive carbohydrate to progress to the large intestine (colon), where there is excessive fermentation by bacteria.4

Basically: expired air is collected, and if it contains excessive hydrogen or methane, the only possible causes are excessive fermentation of carbohydrates by bacteria, either in the small or large intestine (depending on the timing of the higher than normal readings).

How does this SIBO breath test compare with other assessment options?

At Toronto-Centre for Naturopathic Medicine, we use BioHealth Laboratory’s test for SIBO breath testing, which is the most comprehensive option available to naturopathic doctors in Ontario.

The BioHealth Laboratory test:

  1. Measures both expired hydrogen and methane, and
  2. Offers testing using any combination of lactulose, glucose and fructose as test substrates.

These are important considerations, as:

  • 15% or more persons will produce methane rather than hydrogen   with microbial fermentation of carbohydrates. Tests measuring only hydrogen may result in a “false-normal” result for these persons.5
  •  Although measuring glucose fermentation alone is more sensitive (i.e., less likely to miss a diagnosis) than measuring lactulose fermentation alone in assessment of SIBO4, measuring both offers the most accurate assessment of gut bacteria status. Glucose is completely absorbed in the first section of the small intestine4, lactulose is absorbed throughout the small intestine, including the later portion of the small intestine6 and large intestine.Measurement of both allows for the most sensitive assessment of SIBO the first section of the small intestine; (slightly less sensitive) assessment of the later portion of the small intestine; and carbohydrate malabsorption resulting in excessive fermentation in the large intestine. 
  • Fructose malabsorption, although poorly understood as related to digestive symptoms, has been demonstrated to relate to increased severity of IBS symptoms.1

Importantly, breath testing is more reliable for “ruling in” SIBO than “ruling out” SIBO – if breath testing demonstrates you have SIBO, you almost certainly do; if breath testing suggests you do not, you probably do not, but be open to the possibility the test is incorrect.4

Other methods for assessing possible SIBO are:

  1. Bacterial culture – the most direct method, considered by some to be the “gold standard” (other experts are of the opinion no “gold standard” exists for diagnosis of SIBO4), but inconvenient to the patient, and prone to “false-normal” (i.e., incorrectly “ruling out” SIBO) results and contamination in the sampling process1, 4
  2. Urine organic acids testing (OAT) – sometimes suggested as an assessment option, but not diagnostic for SIBO7
  3. Stool analysis – sometimes suggested as an assessment option, but not diagnostic for SIBO7

How can you ensure the most accurate result possible?

Different laboratories suggest different (or no) guidelines for preparing for breath testing, but according to guidelines established in the 2017 Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus statement3, in order ensure the most accurate result possible:

  1. Antibiotics should be avoided for four weeks prior to breath testing.
  2. (If possible), promotility drugs and laxatives should be stopped at least one week prior to breath testing.
  3. Fermentable foods such as complex carbohydrates should be avoided on the day prior to breath testing.
  4. A fasting period  of 8 to 12 hours prior to breath testing.
  5. Smoking should be avoided on the day of breath testing.
  6. Physical activity should be limited during breath testing.
  7. Discontinuation of proton pump inhibitors prior to breath testing is not necessary.

What is the procedure for SIBO breath testing?

This test is conducted at home with a provided test kit.

  1. Beginning 24-hours before beginning the testing procedure, the specified diet must be followed.
  2. Beginning 12-hours before  beginning the testing procedure, the patient must fast.
  3. A baseline breath sample is collected.
  4. The glucose, lactulose or fructose mixture is consumed.
  5. Breath samples are collected every 15-minutes following mixture consumption until all 9 to 12 vials are filled (135 to 180 minutes, depending on test conducted).

In a nutshell:

  1. Consider this laboratory assessment if you have been diagnosed with IBS, or have digestive symptoms, with no identifiable cause.
  2. Measurement of both hydrogen and methane (as opposed to hydrogen only) allows for the  most accurate assessment of SIBO and carbohydrate malabsorption.
  3. Hydrogen/methane breath test using lactulose-only as a test mixture is more affordable (compared to lactulose and glucose test mixtures), and although slightly less sensitive, more reliably assesses the entire length of the small intestine.
  4. Testing for fructose malabsorption may be considered if suffering from severe IBS symptoms.
  5. This test is non-invasive, conducted at home, and requires up to three hours to complete.

Jonah Lusis, ND


  1. Simrén M, Stotzer PO. Use and abuse of hydrogen breath tests. Gut. 2006;55(3):297-303. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1856094/.
  2. Mayo Clinic [Internet]. Irritable bowel syndrome. [cited 2018 Nov 23]. Available at: https://www.mayoclinic.org/diseases-conditions/irritable-bowel-syndrome/symptoms-causes/syc-20360016.
  3. Rezaie A, Buresi M, Lembo A et al. Hydrogen and methane-based breath testing in gastrointestinal disorders: the North American consensus. Am J Gastroenterol. 2017;112(5):775-784. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5418558/.
  4. Ghoshal UC. How to interpret hydrogen breath tests. J Neurogastroenterol Motil. 2011;17(3):312-7. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3155069/.
  5. deLacy Costello BP, Ledochowski M, Ratcliffe NM. The importance of methane breath testing: a review. J Breath Res. 2013 Jun;7(2):024001. doin:10.1088/1752-7155/7/2/024001.
  6. BioHealth Laboratory [Internet]. Small intestinal bacterial overgrowth (SIBO) breath testing.  [cited 2018 Nov 23]. Available at: https://www.biohealthlab.com/test-menu/sibo/.
  7. Siebecker A, Sandburg-Lewis S. SIBO: the finer points of diagnosis, test interpretation, and treatment. Naturopathic Doctor News and Review [Internet]. 2014 Jan 7 [cited 2018 Nov 23]. Available at: https://ndnr.com/gastrointestinal/sibo/.



Posted: 2018 Nov 23

Should I do an elimination diet or do an allergy blood test?

In dealing with inflammatory and irritable bowel diseases, elimination diets and IgG food testing are an important tool in crafting a treatment plan. In this post, Jonah Lusis, ND discusses what they are, and which is preferred.

I suspect my diet may be contributing to my digestive symptoms. Should I do an elimination diet or do an allergy blood test?

You can do either.

The strength of an elimnation diet is that it is a “bottom line” evaluation, asessing whether or not a food causes you to feel unwell regardless of whether the cause is immune-related, intolerance-related or sensitivity-related. It is ideal for conditions in which symptoms are the primary concern, such as irritable bowel syndrome.

Allergy blood testing is for an “IgG immune response” and will only identify foods causing an autoimmune response (i.e., “allergic”).

This approach is recommended for persons having autoimmune (i.e., inflammatory) conditions (e.g., inflammatory bowel diseases, multiple sclerosis, widespread rheumatoid arthritis) because it identifies foods that cause an immune system response, regardless of whether you are aware of symptoms in the digestive tract.

The bottom line:

  • Irritable bowel disease: elimination diet > IgG assessment (but IgG assessment can be helpful if an elimination diet is not possible)
  • Inflammatory condition: Do an IgG assessment

In our final post for Crohn’s and Colitis month, Jonah Lusis, ND will explain the difference between a food allergy test administered by an MD and an IgG test.

Let us know if we can help (with your digestive health or otherwise)!


Posted: 2014 November 20

What is an Elimination Diet?

Continuing our conversation on improving digestive health, Jonah Lusis, ND discusses in this two-part question, an elimination diet and its benefits in treatment.

What is an elimination diet?

An elimination diet is a therapeutic diet used to identify foods a person doesn’t tolerate well.

There are various versions of an elimination diet, depending on the specific health concern being addressed, but at their core they will feature removal of foods most people are either allergic to or do not tolerate well, but are commonly eaten. Examples of commonly “eliminated” foods are dairy products, wheat and eggs.

The goal of the diet is to confirm whether or not the persons symptoms abate in the absence of these foods.

An elimination diet will typically last three weeks.

I have already removed foods I suspect are causing my symptoms, do I need to complete an elimination diet?


It is important to remove all suspect foods simultaneously. For example, if you do not tolerate wither wheat or dairy, and have removed them from your diet, but not at the same time, you many have concluded: while not having wheat, but feeling unwell from the dairy you are still consuming, that wheat is not causing your symptoms. The same applies in reverse. This can lead to the ultimate conclusion that neither wheat or dairy or your problems foods when in fact both are.

Tune in next week when we will discuss gluten: the good, the bad, and the ugly.

For more help with elimination diets and digestive symptoms, get in touch!



Posted: 2014 November 6


What is the difference between the food allergy test I have had with my MD, and an IgG allergy test?

In our last “Ask the Doctor” post for Crohn’s and Collitis Month, Jonah Lusis, ND answers a commonly asked question about IgE and IgG food testing.

What is the difference between the allergy test I have had with my MD, and an IgG allergy test?

The allergy test you have with your MD is usually a “skin-scratch” test. This test evaluated whether your body has an IgE (a type of immune system chemical) response to foods. The IgE response is the “immediate” response (e.g., hives, throat constriction) your immune system mounts to foods you are allergic to.

An IgG allergy assessment (such as this one) is a blood test that evaluates foods that trigger an IgG (a second, different immune system chemical) response by your body that also produces inflammation, but is typically delayed, and therefore more difficult to detect (e.g., migraine headaches, eczema).

Jonah Lusis, ND

We hope you enjoyed our digestive health series!

If you are struggling with digestive issues and are ready to get you tummy on track, we can help.


Posted: 2014 November 27