What is Small Intestinal Bacterial Overgrowth?
Small Intestinal Bacterial Overgrowth or SIBO is a common yet under-recognized problem. SIBO is characterised by the presence of an abnormal number of bacteria in the small intestine in combination with a host of GI symptoms. Bacteria that normally live in the large intestine, move up to the small intestine area where it does not belong!
Testing for SIBO
Getting an accurate diagnosis of SIBO can be incredibly difficult. The condition often goes undiagnosed as it is a relatively new concept in the scientific literature and research is evolving every day in this area.
Testing for SIBO typically involves a hydrogen and methane breath test. During bacterial overgrowth, we produce elevated levels of gases such as hydrogen and methane (these are produced by the bacteria and cause gas and bloating) which are exhaled through breath. These gases allow us to measure bacterial load in the small intestine.
There are limitations to this test though with several researchers and practitioners questioning the accuracy of this test to identify SIBO. It has been suggested that some bacteria in the small intestine produce hydrogen sulphide rather than methane or hydrogen. At this stage, we do not have a test for hydrogen sulphide.
Before an SIBO breath test, there are important nutritional preparation steps that must be taken up to 2 weeks before the test for an accurate reading.
There is also potential for the overgrowth of fungus in the small intestine (SIFO) which can cause symptoms very similar symptoms of SIBO. However, there is currently no test available for SIFO.
Different types of SIBO
There are three main types of SIBO; methane, hydrogen, and hydrogen sulfide. These are the three main gases produced by bacterial overgrowth in the small intestine.
- Methane SIBO
- This is diagnosed by the elevation of methane on a SIBO breath test. Specifically, M.smithii bacteria account for 94% of species that produce methane. Everybody has M.smithii bacteria however it depends on how much you have. The higher amounts of M.smithii in their stool will typically have higher methane levels on a breath test. Methane has been shown in the literature to decrease GI transit time. This may lead to constipation and excessive bloating which is a major symptom for methane SIBO. The annoying this about methane SIBO is these bugs can be antibiotic and antimicrobial-resistant. It was making healing longer and more difficult.
- Hydrogen SIBO
- This is typically the most prevalent SIBO and is diagnosed by the rise in hydrogen on a SIBO breath test, as a result of carbohydrate-fermenting bacteria that produce hydrogen gas in the small intestine. The issue arises when we have too much bacteria in the small intestine producing hydrogen. Increased hydrogen production is often associated with loose stools or diarrhea, bloating, and GI discomfort.
- Hydrogen Sulfide SIBO
- Hydrogen sulfide SIBO is quite new and research is still merging on this type of SIBO. Sulfur is an essential mineral that plays a role in amino acid composition, energy production, and metabolization of food, it protects us against oxidative stress and contributes to the health of our skin, tendons, and ligaments. This issue occurs when there is too much hydrogen sulphur which overwhelms our gut due to detoxifying which can become problematic and lead to intolerance to sulphur-containing foods (onion, garlic, eggs, cruciferous veggies), leaky gut, foul smelling gas, brain fog, and leaky gut. If you have this form of SIBO you will need to follow a low-sulfur diet. Interestingly, research has shown a low-FODMAP diet is not beneficial for hydrogen-sulfide SIBO.
The root cause of SIBO
Finding the root cause of your SIBO is going to be vital in your healing and bringing balance back to your gut and your body. Some underlying causes of SIBO include;
- Hypothyroidism – low thyroid function has a direct impact on your gastrointestinal health and affects overall gut motility which can predispose you to SIBO
- Chronic Stress – when you are in a constant state of fight or flight your gastric function is reduced which can make you more susceptible to SIBO
- Excess Estrogen – Excess estrogen can decrease the production of bile salts (this is required to break down and assimilate fats) but they also have antimicrobial properties and a deficiency can be a predisposing factor for SIBO.
- Adhesions and Scar Tissue – if the structure of the small intestine is compromised this increases the likelihood of SIBO developing.
- Lowered Immune Function – when the immune system does not work correctly it cannot remove bacteria out of the small intestine which allows it to overgrow.
- Low Stomach Acid – this can typically be caused by stress and/or low zinc, B12, and low chloride, and overuse of PPIs and NSAIDs. HCL protects the stomach and kills bacteria before it can enter it. If you have lowered stomach acid it predisposes you to SIBO. Side note; if you have had H Pylori this also lowers stomach acid.
- Oral Contraceptive Pill – Yes, the pill can lead to SIBO, yeast infections, gut dysbiosis, and even autoimmune issues.
How to treat SIBO
Firstly, you need to understand which type of SIBO you have and ensure you followed all the appropriate steps before your testing (as I mentioned nutritional alterations from 2 weeks out) so you know you have an accurate result.
There are nutritional, training, and lifestyle interventions that will need to take place depending on which type of SIBO you have for you to heal appropriately.
For hydrogen and methane SIBO you may need to follow a low-FODMAP diet for some time while you are eliminating the SIBO. But you do want to ensure you reintroduce FODMAPS at some point as they are vital for the health of our gut and colonization of good gut bacteria. For hydrogen sulfide SIBO a low-sulfur diet is generally recommended until irradiation is confirmed.
You will need to eradicate the bacteria through the use of herbal antimicrobials along with other supplementation (generally fibre and probiotics). Depending on your type of SIBO, symptoms, and any other issues will depend on what course of antimicrobials your practitioner may suggest. Along with addressing any nutrient deficiencies that can lead to gut inflammation.
Along with reducing stress, focusing on recovery, sleep quality, self-care, and reducing training load whilst healing are all vital steps in your recovery
Mandy x
