How do you test for SIBO?

In the past doctors measured the fluid in the small intestine directly using an endoscope or a colonoscopy to see how many microbes were present. However, this method is invasive and expensive. An easier, less invasive method that is now well established is breath testing.

SIBO breath testing works by first drinking a sugar solution. If there are excess bacteria in the small intestine, they will produce gas. This gas is absorbed into the bloodstream before transferring to the lungs. Producing gas is normal but if you exhale an excessive amount within a certain time this indicates that there could be an overgrowth of microbes.

The type of gas produced during a breath test will depend on the type of microbes present. Most positive SIBO breath test results will be down to hydrogen-producing bacteria. However, in some cases, the symptoms will be caused by methane-producing microbes (approximately 5-10%). More recently, a 3^rd gas has been tested for, hydrogen sulphide. It’s less common, but hydrogen sulphide produced during a breath test may also indicate SIBO. When the culprits are methane producers, constipation tends to be more common. Whereas with hydrogen dominant SIBO, either diarrhoea and/or constipation may occur. Additionally, early data suggests that a positive SIBO test based on hydrogen sulphide is more commonly linked with diarrhoea. It is important to note that these are only common associations and not everyone fits the same pattern. However, determining which gas is present can be helpful information for your doctor as they can tailor the treatment to your needs.

Some doctors will diagnose SIBO based solely on symptoms. This is often the case due to a lack of access to breath testing services. This is something that we are trying to change at FoodMarble. It is important because, given the overlap in symptoms with other conditions and the risks associated with unnecessary antibiotic treatment, a lot of researchers recommend that an objective test like breath testing should be the first step in the diagnosis. Studies have shown that those that have a positive breath test are more than twice as likely to identify those who respond to treatment.

Can SIBO be treated?

The good news is that SIBO is treatable. However, it’s not as simple as just getting rid of the intruding microbes. As it is a complex condition where the underlying causes are not always clear, SIBO treatment can take time.

A comprehensive SIBO management plan typically includes some or all of the following phases:

SIBO clearance:

• Eradication of the overgrowth using antibiotics. Rifaximin is often used for hydrogen positive and hydrogen sulphide positive cases. A combination of Rifaximin and Neomycin is commonly used for those who have methane present. For some, you may require more than one dose. It is important to track your gas levels to see if you have responded. Symptoms alone are a less reliable indicator as other conditions may be present, e.g. IBS, IBD functional dyspepsia.
• Herbal antibiotics: For some prescription antibiotics are not available or not desired, so herbal antimicrobials are used. There is some evidence that they can be effective. It is important to discuss your options with your doctor.
• Nutrient replacement: Since absorption of nutrients can be inhibited, some will require nutritional support, particularly in cases of malnutrition or weight loss. This can be achieved using nutrient supplements to encourage gut healing.

Post-treatment:

• Root cause identification: Trying to identify the root cause is important as it will likely return (relapse can occur in up to 60% of SIBO cases). Possible causes may include impaired motility, side effects of medications, physical obstructions, or digestive defects such as low stomach acid.
• Dietary modification: Once gas levels have normalised, dietary modifications can be used to help reduce any remaining symptoms. This often includes the low FODMAP diet. Often patients who suffer with SIBO also have at least one food intolerance, e.g. lactose intolerance.
• Relapse monitoring: Ongoing monitoring to prevent relapse. Your FoodMarble AIRE or AIRE 2 can help you to keep track of your gas levels and symptoms during and after treatment.

SIBO & Antibiotics

In terms of dealing with the initial overgrowth, antibiotics are often the first course of treatment for many doctors. A small number have been studied specifically for SIBO. Of these, Rifaximin has been most thoroughly investigated. It has been shown to eradicate SIBO in 70% of cases. There is also a growing body of evidence demonstrating the benefit of herbal antimicrobial. Studies have shown that herbal treatment can be at least as effective as antibiotics. The types of microbes responsible for SIBO can vary from person to person so combination therapies are sometimes used to target specific microbes.

It may seem counterintuitive to involve probiotics i.e. live bacteria when the problem is too many microbes, but some studies have been carried out investigating their use in SIBO treatment. The evidence is mixed, with some studies showing they can be useful when combined with antibiotics. Others have shown that probiotic bacteria may cause further microbial imbalance and worsen symptoms. The current thinking among many researchers is that probiotics should not be used in eradicating the initial overgrowth of microbes.

SIBO and Diet

Just as we are what we eat, so are our gut bacteria, including the harmful ones. So, it stands to reason that if we eat what they like it will make it harder to get rid of them. While if we reduce our intake of fermentable carbohydrates, we can minimize the fuel that allows the offending microbes to cause symptoms.

While there is a lot of evidence showing that a diet low in fermentable carbohydrates such as the Low FODMAP diet can reduce symptoms in those with IBS, to date there have been very few studies examining diet as a treatment or management strategy specifically for SIBO. Other elimination diets such as the Specific Carbohydrate Diet and the Elemental Diet have been shown to reduce intestinal gas production and relieve symptoms in some digestive disorders but not for SIBO. Despite the lack of clinical evidence elimination diets are used in practice as a strategy to reduce SIBO related symptoms. As treatment can take time it is important to devise a diet plan that will help minimize symptoms but maintain your nutrient levels and fibre intake.

Next Up

In the final instalment of our SIBO blog series, we will look at the connections between SIBO and IBS, as well as some other digestive disorders and related conditions. Finally, we will tell you how our AIRE and AIRE 2 can come in handy when it comes to SIBO.