Gut Health

Is your IBS caused by SIBO?

As a follow-up to last week’s topic of Histamine Intolerance (HIT), I wanted to take a deeper dive into one of the common underlying causes of HIT, which is called SIBO: Small Intestinal Bacterial Overgrowth.

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What is SIBO? What are its symptoms?
SIBO is a condition in which bacteria (or another organism called archae) overgrow in the small intestine, causing a variety of symptoms and health problems. The small intestine is usually a relatively sterile environment, but in SIBO, bacteria from the colon migrate upwards into the small intestine, where they ferment fibers and specific sugars found within food and produce gas, which can lead to bloating, abdominal pain, burping, flatulence, heartburn, nausea, diarrhea, and/or constipation. The bloating tends to be high in the abdomen, above the belly button. Many patients report zero bloat upon waking meanwhile they may need to change their choice of pants by early evening. A common phrase I hear in my office is, “I look this many months pregnant”. These symptoms are usually happening daily, and can be significantly debilitating for some people. We have trillions of beneficial bacteria in our colon (as much as we have cells in our entire body!), but they cause BIG problems when they creep up into the small intestine.

What causes SIBO?
SIBO can develop due to a variety of factors, the primary reason being dysfunctional motility in the intestines (also called a dysfunctional migrating motor complex or MMC). The most well understood reason our MMC may become damaged and faulty, is second to a case of food poisoning or traveller’s diarrhea. Other causes include low stomach acid, bile insufficiency, intestinal strictures (think, history of abdominal surgery), and MMC changes due to Celiac disease, Inflammatory Bowel Disease, or Diabetes. Additionally, certain medications, such as antibiotics, can disrupt the balance of gut bacteria and increase the risk of SIBO. Even concussions and TBIs may be an underlying risk factor for SIBO, damaging the MMC and triggering increased intestinal permeability (aka leaky gut). Some patients can point to an obvious trigger (e.g. some bout of acute gastroenteritis or a concussion) in which their digestion was never the same, but I find that the majority of patients can’t.

How to find out if you have SIBO?
I always, always, always recommend testing for the presence of SIBO rather than a trial of treatment. As its symptoms are often similar to those of other gastrointestinal disorders, you want to make sure you indeed have SIBO (or not) before you go mucking around with treatment. A specific breath test is the gold-standard diagnostic tool for SIBO; it measures the amount of hydrogen and methane gas produced by the organisms in the gut. 

Associated conditions
Oof – the list here is extensive. If you experience digestive disturbances and one or more of the following conditions, SIBO testing may be a good idea:

  • Unexplained chronic anemia or iron deficiency
  • A diagnosis of GERD or dyspepsia (aka indigestion) – I like to ensure H. pylori is tested first, however, new research has suggested H pylori may be its own causative agent of SIBO, or the two can coexist
  • Interstitial Cystitis 
  • Autoimmune diseases like Hashimoto’s or Rheumatoid arthritis
  • Acne and Rosacea
  • Non Alcoholic Fatty Liver – especially in the absence of other risk factors
  • Lactose intolerance
  • Leaky gut syndrome
  • Restless leg syndrome (RLS)
  • Hypothyroidism
  • And much more.

Also, besides antibiotics, the following medications may increase your risk of developing SIBO when used long term: 

  • Acid blocking medications called Proton Pump Inhibitors (PPI’s)
  • Pain medications, such as NSAID’s (e.g. Advil/Ibuprofen, Naproxen, Motrin, etc.) and Opiates 

Treatment options
Treating SIBO involves either pharmaceutical or botanical antimicrobials. I use a step wise process: first you need to get the bacteria out of the small intestine, then you need to make sure the MMC (motility) is in top top shape, before replenishing with beneficial bacteria. Next steps include healing up any leaky gut and restoring stomach acid and bile production; whole body treatment is imperative to prevent relapse.There is this idea that SIBO is often recurrent or relapsing. I don’t see this, as long as all the underlying causes are addressed. The antimicrobial phase alone is not enough (you may achieve 100% symptom resolution but if you don’t fix what caused the SIBO to develop in the first place, then yes, it may re-grow). I don’t broadly have patients follow a low FODMAP diet – I want to see successful symptom resolution even while eating these foods. A low FODMAP diet can be a band-aid solution and isn’t a good management option long term as it can lead to nutrient deficiencies due to its restriction of nutrient dense and health promoting foods. We want and need these foods in the diet, we just need you to be able to digest and tolerate them ( like you should be able to when the body is working properly). 

I 🧡 treating IBS because it can be physically and emotionally debilitating. I have had patients that will barely travel outside their home or avoid eating all day until Suppertime because their symptoms affect their ability to work. I’ve had patients delay post-secondary education because they can’t make it through the day. The cases I’m thinking of were all properly worked up conventionally, but SIBO is a fairly new condition, with Health Canada only approving the antibiotic of choice in the Spring of 2019.

Most patients come to me believing what they have been told, that there are no curative treatments, only symptom management (e.g. Buscopan – an antispasmodic medication, antidepressants, or acid blocking medications to name a few). Meanwhile, if you successfully treat SIBO, all of your IBS symptoms can go away, permanently, while being able to tolerate FODMAP foods again (yes, I’ve seen it time and time again, but always remember, just because we rule in SIBO doesn’t mean it is the SOLE cause of your IBS; maybe more on that another day…)

Any questions? Drop ‘em below.

- Dr. Willow

  1. Marian Voth says:

    I have nearly constant stomach pain (not severe) and abdominal swelling. I also feel tired most of the time, falling asleep in the middle of the day. I am a diabetic and take Metformin (1 – 2 per day), Tresiba (32 units per day), and Ozempic since October, 2022 (1 unit per week). I have a young, male doctor who is just fine but I miss my older, female doctor who retired. Do you think your upcoming gut program might be a good fit for me?

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I help women achieve optimal digestive and hormonal wellness through a root cause, individualized approach to medicine that utilizes functional lab testing, diet and lifestyle modification, nutritional and herbal medicine, and acupuncture to re-establish lasting health.


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