SIBO – Small Intestinal Bacterial Overgrowth

An estimated 6-15% of healthy people have SIBO, and up to 80% of people with irritable bowel syndrome (IBS) have SIBO. I often suspect SIBO in my patients when they say they feel bloated, uncomfortable, and have bowel irregularities “no matter what I do or eat”.

What is SIBO?

SIBO is an overgrowth of bacteria in the small intestine. In a normally functioning gut, there is a small number of bacteria that colonize the small intestine, and a much, MUCH larger number of bacteria that colonize the large intestine. As food travels down the digestive path it reaches the small intestine first, where further breakdown of the food and absorption of nutrients occurs. Next, the food reaches the large intestine (where it encounters more bacteria) and there, the gut re-absorbs water and bulks up the soon-to-be stool.

In people with SIBO, there is an overgrowth of bacteria in the small intestine with bacteria that should normally be found in the large intestine. This excess bacteria feasts on food particles in the small intestine before it has the chance to be fully broken down and absorbed. This causes bloating, abdominal pain, constipation/low motility or diarrhea, and/or gas. In some patients it also causes severe nausea and sometimes vomiting.t

The bacterial overgrowth also causes inflammation that damages the lining of the small intestine. As a result, we get reduced absorption of certain nutrients like vitamin A, B12, and D, and an increased amount of food intolerances and inflammation in the body.

What causes SIBO?

A variety of factors can alter the amount of bacteria living in the small intestine. Low stomach acid, taking antacid medications, antibiotics, being on the birth control pill, and drinking alcohol are common causes of SIBO. It has also been very closely linked with post-concussion syndrome (head injuries), hypothyroidism, and a history of traveller’s diarrhea.

How is SIBO diagnosed?

Breath testing is the primary test used to diagnose SIBO. It measures hydrogen and methane produced by bacteria in the small intestine that is exhaled from the lungs over the next two to three hours.

To do the test, patients drink a solution of lactulose, which is a sugar that only bacteria can break down. After bacteria consume lactulose they produce a gas, which is reflected in levels of hydrogen and methane measured on the breath test. A glucose breath test can also be used to diagnose an overgrowth in the first two to three feet of the small intestine where humans normally absorb glucose, but a lactulose test is the most commonly used form of testing.

Testing can be done at home using a SIBO test kit. I recommend a three hour lactulose breath test for the most comprehensive results. It’s important to note that you must follow a strict test prep protocol prior to testing for accurate test results.

How is SIBO treated?

To treat SIBO, the overgrowth of bacteria in the small intestine must be killed. Protocols vary based on the type of bacteria in the bowel and severity of the patient’s case. I typically send patients to their MD for a Rifaximin antibiotic prescription, and also start them on a combination herbal antimicrobials to increase the success rate of antibiotic alone. It is also important to disrupt bacteria’s defence system (called a biofilm) by using supplements like NAC and certain enzymes. I always also recommend liver support to assist with the detoxification process and efficacy of treatment.

Dietary changes must also be made to starve the bacteria and prevent reoccurrence of SIBO. I recommend a modified combination of the low FODMAP and Specific Carbohydrate Diet, and give my patients a specific foods to eat and foods to avoid, including portion sizes and meal plan resources.

After SIBO eradication, we may have to address the gut flora in the large intestine as a secondary treatment step, as yeast overgrowth often becomes a secondary issue.

Next, we repair the bowels using a protein called L-glutamine and some specific herbs to support the growth of healthy gut flora. A strict adherence to the dietary plan is crucial at this stage. It’s important to note that we never use probiotics that can re-colonize the small intestine, and I am very specific about the strains that we use, if any at all.

SIBO can recur in up to 50% of patients, so it’s important to monitor the diet and eliminate the factors that may have initially caused the SIBO. I work with patients to determine and treat their risk factors for SIBO reoccurrence, which may include increasing stomach acidity, liver support, and long term nutrition plans.

SIBO and Mood

In about 95% of SIBO cases I have seen, there is a very strong emotional component that needs to be addressed. It’s important to know that our serotonin hormone, which is responsible for anti-anxiety, anti-depression, appetite control, and more, is 90-95% produced and stored in the gut. When our gut is off, we experience low mood and anxiety because we’re less able to regulate our serotonin production. This is made even more difficult for SIBO patients because SIBO prevents us from absorbing many nutrients from food, so we lack the building blocks we need to to support our mood and energy.

SIBO patients also typically have a very difficult relationship with food and their body. Food has been making them feel sick for so long, and the SIBO diet can be so restrictive, that they usually feel a lot of anxiety and fear surrounding eating.

I often spend a lot of time with patients after their SIBO eradication to help them feel confident and in control about their body and their relationship with food. We always replenish nutrient stores, and often support serotonin levels to ensure that improving mood and energy is addressed as part of our SIBO treatment program.