Dr. Heidi Lescanec, NDFunctional Medicine, Naturopathy


Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, estimated to effect about 12% of the Canadian population (1). It is characterized by a vicious cycle of recurrent abdominal pain, and altered bowel habits (i.e., constipation, diarrhea or both), often accompanied by bloating (2). Studies suggest that between 65 to 78% of people affected by IBS actually have SIBO as the underlying cause of the syndrome (3, 4).

What is SIBO?

Small Intestine Bacterial Overgrowth is the chronic overgrowth of bacteria in the small intestine. Bacteria normally live in the gastrointestinal tract, but not in this particular location- they should primarily be in the colon, or the large intestine, where waste is removed from the body. When bacteria are in abundance in the small intestine, they interfere with the normal digestion and absorption of food. This can lead to damage to the lining of this vital digestive tract, resulting in what is commonly referred to as “leaky gut” or intestinal permeability.

Here are some symptoms associated with SIBO:

– Bloating
– Constipation +/or Diarrhea
– Flatulence (Gas) or Belching
– Abdominal pain or cramps
– Nausea
– Heartburn (reflux or GERD)
– Food Sensitivities
– Joint pain
– Fatigue
– Skin rashes

When I see someone in the clinic who presents with the symptoms above, here are some of the “red flags” that make me think we should test for SIBO:

Indications of SIBO:

– IBS after an episode of acute gastroenteritis (food poisoning or stomach flu)
– Dramatic (temporary) improvement in IBS symptoms after taking antibiotics
– Worsening of symptoms after taking FOS/prebiotics or increased fiber intake
– Low iron or vitamin B12 levels for no apparent reason (for example eating a diet with foods that contain both)
– Lack of improvement in celiac patients despite being gluten-free
– Chronic constipation after taking opiate medications
– Abdominal surgeries that commonly create adhesions

Associated Syndromes and Conditions with SIBO:
– Acne Rosacea
– Chronic Fatigue Syndrome
– Fibromyalgia
– IBD (Crohn’s, Ulcerative Colitis)
– Interstitial Cystitis
– Restless Leg Syndrome
– Rheumatoid Arthritis

How is the test done?

Breath testing measures the hydrogen and methane gas produced by bacteria in the small intestine that has diffused into the blood, then lungs, and expired. These gases produced by bacteria, not by humans. The gas is graphed over three hours and compared to a research-derived baseline measurement. You drink a solution of lactulose after a one- or two-day preparatory diet. The diet removes much of the food that would feed the bacteria, allowing for a clear reaction to the sugar drink.

Is the breath test accurate?

Sampling the contents of the small intestine is challenging. Endoscopy only reaches into the top portion, and colonoscopy only reaches the last portion. The middle portion (about 17 feet) is not accessible, other than by surgery. Stool testing predominantly reflects the large intestine. False positives are rare and caused by improper preparation or collection. False negatives are avoided by measuring methane in addition to hydrogen. (5, 6)


There are effective prescription and natural treatment options for SIBO
Two phases are critical for a successful treatment.

Antimicrobial Medicines:
Prescription Antibiotics (2 weeks) or Botanicals (4-6 weeks) (7)
Saccharomyces Boulardi (a probiotic yeast)

Diet: LOW FODMAPS, Specific Carbohydrate Diet or the SIBO Specific Diet- 1 month maximum (8).
Motility/ Prokinetic agents
Heal Leaky Gut/Intestinal Permeability

An important fact to point out is that SIBO is not the same as a bacterial infection like strep throat. In the case of a simple infection of the throat, you may take an antimicrobial agent (like antibiotics) and have it clear up after a few days—quick relief!

There are a few reasons that SIBO is more complex condition to resolve.
#1 Something in the GI (gastrointestinal) system has to go wrong first before SIBO can develop —it isn’t just the bacteria that are the problem.
#2 Successful treatment involves restoring the proper function of this GI system (digestion, absorption and elimination) and addressing the underlying root cause that allowed SIBO to take develop in the first place.

Fortunately, naturopathic medicine is well-equipped to identify these root causes and offers a comprehensive approach to restoring the proper function of your digestive system– ultimately stopping the vicious cycle of IBS!







Thompson WG, Irvine EJ, et al. Functional gastrointestinal disorders in Canada: First population-based survey using Rome II criteria with suggestions for improving the questionnaire. Dig Dis Sci 2002;47(1):225–35.

Lacy BE, Mearin F, Chang L, et al. Bowel disorders. Gastroenterology 2016;150:1393– 407

Pimentel M, Chow EJ, Lin HC. Eradication of small intestinal bacterial overgrowth reduces symptoms of irritable bowel syndrome.
Am J Gastroenterol. 2000 Dec;95(12):3503-6.

Giamarellos-Bourboulis EJ, Pyleris E, et al.
Small intestinal bacterial overgrowth is associated with irritable bowel syndrome and is independent of proton pump inhibitor usage. BMC Gastroenterol. 2016 Jul 11;16(1):67.

Pimentel M, Chow EJ, Lin HC. Normalization of lactulose breath testing correlates with symptom improvement in irritable bowel syndrome. a double-blind, randomized, placebo-controlled study. Am J Gastroenterol. 2003 Feb;98(2):412-9.

6. Shah E, Basseri RJ, et al. Abnormal breath testing in IBS: a meta-analysis. Dig Dis Sci. Digestive Diseases and Sciences 2010 Sep;55(9):2441-9.

Chedid V, Sameer Dhalla S, et al, Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med. 2014 May; 3(3): 16–24.

Moayyedi P, Andrews C. , et al. Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Irritable Bowel Syndrome (IBS) Journal of the Canadian Association of Gastroenterology, 2019, XX(X), 1–24.

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