SIBO vs IBS

Did you know that the symptoms of IBS are similar to those experienced by people with Small Intestinal Bacterial Overgrowth (known as SIBO)?

What is SIBO?
SIBO is diagnosed when there is an excessive amount of bacteria within the small intestine. In a healthy digestive system, the amount of gut bacteria found within the small intestine is quite low, so when there is an excessive amount of bacteria it is often the result of some anatomical abnormality or digestive illness.

It is estimated that anywhere from 4% to 78% of patients with IBS also have SIBO – that's a pretty wide gap! But this is due to the fact that the medical community hasn't landed on one standardised test for diagnosing SIBO.

People who suffer from both IBS and SIBO experience:

• Bloating
• Abdominal pain or discomfort
• Flatulence
• Irregular bowels

So how is SIBO diagnosed?

Most cases are diagnosed through the use of hydrogen breath testing. There are two types of hydrogen breath test used to diagnose SIBO: the Lactulose Breath Test (LBT) and the Glucose Breath Test (GBT). Both tests measure concentrations of hydrogen and methane in the breath.

You will be asked to drink a sugar solution and then provide samples of your breath at various intervals. If hydrogen or methane are detected within 90 minutes, SIBO will be diagnosed.

The length of time is key, since it generally would take two hours for the sugar solution to make its way to the large intestine, any rise in these gases prior to that time suggest that the sugar was acted upon by bacteria within the small intestine. This method has considerable diagnostic limitations…it lacks sensitivity and specificity, which means there is a high chance of getting a false positive or false negative result.

The best method to diagnose SIBO is via sampling fluid from the small intestine and growing the bacteria found in this fluid to estimate if a very high number of bacteria are present. Because it is an invasive procedure, it is rarely used in clinical practice unless a gastroenterologist thinks it's necessary.

How is SIBO treated?

After you've been diagnosed with SIBO, the primary form of treatment is the use of a certain type of antibiotic – the type of antibiotic chosen for the treatment of SIBO is one that is not absorbed in the stomach and therefore makes its way to the small intestine where it can eliminate any bacteria it finds there. Although such antibiotics have been shown to be effective, they are not yet approved by the FDA for use in IBS. Another form of treatment uses oregano oil capsules for 3-6 weeks in specific dosages set by your gastroenterologist or dietitian. 

Please note that SIBO can recur even after you have been successfully treated initially.

Diet Intervention

Because SIBO shares almost all the same symptoms as IBS, researchers suspect a low FODMAP diet may be beneficial for SIBO patients since there has been much success seen with IBS patients. A low FODMAP diet would cause the problematic bacteria to "starve" in the small intestine.

Please note that a low FODMAP diet should be monitored by a professional and a SIBO patient should not start on this diet until they have finished a course of antibiotics.

SIBO patients might also want to try probiotics. A small study found that daily probiotics altered fermentation patterns in their intestines, which was consistent with reducing SIBO.

If you want to learn more about the low FODMAP diet and its impact on IBS sufferers, don't hesitate to enrol in my self-directed online course, Beat the Bloat! It has a wealth of information about different gut conditions, what your symptoms may be telling you, IBS, the low FODMAP diet, and other non-FODMAP triggers.