Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder for which no known physiologic or anatomical cause has been identified. IBS involves problems with the movement of food through the intestines, or what we call motility, and how the brain interprets signals from the intestinal nerves.
According to the Canadian Digestive Health Foundation, IBS affects an estimated 5-10% of the Canadian population, more than 70% of those people say that their symptoms interfere with their everyday life and 46% report missing work or school because of it. That’s a sad state of affairs, if you ask me.
The Rome IV criteria is the most recent and well-known diagnostic criteria for IBS:
On average, > 1 day per week in the last 3 months of recurrent abdominal pain, plus 2 or more of the following:
Symptoms are related to defecation
Onset of symptoms are associated with a change in frequency of stool
Onset of symptoms are associated with a change in stool form or appearance
Pretty vague, right? So you have abdominal pain that may or may not be associated with defecation, and/or a change in stool.
IBS is what we call a “diagnosis of exclusion”, which means that once you’ve ruled out the other causes of your symptoms and you fit the Rome IV criteria above, you are diagnosed with whatever is left over, IBS.
“Irritable bowel syndrome is a lazy diagnosis”
I couldn’t agree more with my colleague’s quote. If you’re reading this, you likely have some troublesome gut symptoms and might be thinking “great, so what’s a girl to do if she has IBS?”. If you’re like most of my patients who’ve been diagnosed with IBS you probably haven’t had much relief with conventional medicine. We’ll talk more about treatment in the follow-up article.
Enter naturopathic and functional medicine, which aim to investigate and treat the cause of the disease or dysfunction. As a naturopathic doctor who practices from a functional perspective, when a patient has been given the diagnosis of IBS or they have any digestive symptoms, I always have SIBO near the top of my differential diagnosis list. I put on my medical detective hat and get to work trying to sort out the why and how my patient got to where they are and how I can get them back to a state of thriving.
SIBO stands for small intestinal bacterial overgrowth, which means just that – an overgrowth of bacteria in the small intestines. Most of our gut bacteria should be hanging out further along, in our large intestines. But, for a variety of reasons, which we’ll discuss later on, they end up migrating further up into the small intestines, fermentating fibers in our food, which produce gases, leading to some of the following symptoms.
abdominal bloating or distention after meals
abdominal discomfort or pain after meals
excessive burping or gas
nausea
heartburn or reflux
a sensation of fullness and slow digestion
chronic loose stool or diarrhea
chronic constipation
alternating loose stool and constipation
urgency
steatorrhea or greasy appearing stool
I may be more inclined to think of SIBO if the patient history also reveals;
a history of heavy antibiotic use
a history of proton pump inhibitor (PPI) use (for example nexium, prilosec, prevacid)
symptoms that are worse with sugary, or fiber rich foods such as fruits and veggies
a history of gall bladder removal
worsening symptoms with probiotics or fermented foods
worsening symptoms after a stomach bug or a concussion
improvements in symptoms while following a low fiber or low FODMAP diet
I bet you’ve noticed there’s a bit of overlap between the symptoms of SIBO and those of IBS. You’re on to something! In fact, up to 84% of IBS sufferers test positive for SIBO.
What causes SIBO?
There are many different potential root causes and contributors to the development of SIBO.
A dysfunctional migrating motor complex (or MMC), which is the complex that sweeps food and bacteria from your small to large intestines after you eat, is by far the #1 root cause of SIBO, correction of which is imperative for long-term resolution of symptoms.
The leading cause of a dysfunctional or weakened MMC is bacterial gastroenteritis (read: a bad tummy bug) also known as traveler’s diarrhea, or food poisoning. Other causes include low stomach acid, bile insufficiency and bile de-conjugation, traumatic brain injury or concussion, intestinal strictures or adhesions or ileocecal valve dysfunction.
Many common conditions have been associated with SIBO including:
Iron and vitamin B12 deficiency
Intestinal permeability
Non-alcoholic fatty liver disease or NAFLD
Rosacea
Interstitial Cystitis
Hypothyroidism
Restless Leg Syndrome
Histamine Intolerance
Let’s not forget some basic science – association doesn’t equal causation – so it’s not that these conditions cause SIBO, or are caused by SIBO, but are merely associated with SIBO. However, I have seen some of these conditions improve when SIBO is dealt with properly, so if you have a refractory (non-responsive) case of any of these you may want to investigate and treat SIBO.
Is there a test for SIBO?
Thankfully, there is. If it’s indicated, I’ll recommend doing a 3-hour lactulose SIBO breath test, which looks for two different gases, hydrogen and methane. These gases are produced by the bacteria in small intestines and can cause the disruptive symptoms we talked about above. If the gas levels meet the diagnostic criteria for SIBO, we start treatment and patients typically start to feel better in as little as 3 weeks.
Stay tuned for part II, when I’ll discuss SIBO test results, steps for treating SIBO, and how to mitigate relapse.
Have you been diagnosed with IBS or think you might have SIBO? Feel free to book an initial visit or a complimentary meet the doctor below.