SIBO

What is SIBO & SIBO testing?

First of all, what is SIBO? SIBO stands for Small Intestinal Bacterial Overgrowth. It is defined as the presence of excessive bacteria in the small intestine. The problem is that there are too much bacteria and/or the wrong type of bacteria present in the wrong place.

Symptoms can be excess/trapped gas, bloating, diarrhea and/or constipation, abdominal pain or cramping, food sensitivities, chronic fatigue, brain fog, and the list goes on. (1)(2)

Before getting tested

Before getting to SIBO testing, many people try different methods to relieve their symptoms. These approaches may include lifestyle changes (e.g., reducing sugar/junk and processed food consumption; stress; getting more sleep) or eating more fiber, prebiotic foods, and herbs. However, if these changes don’t bring the expected results or make the current symptoms worsen, then it might be time to visit the GI doctor to have some tests.

Although having the symptoms mentioned above doesn’t mean that you have 100% SIBO. It is crucial to rule out other diseases (like endometriosis, Crohn’s/ Colitis) and get a proper diagnosis by your healthcare practitioner. There can be many different diseases, which could cause the same symptoms.

Suppose you have already been diagnosed with IBS (Irritable Bowel Syndrome). In that case, it is definitely worth getting SIBO testing because, according to a study, up to 84% of patients with IBS actually have SIBO. (3)

It may also happen that a person thought SIBO was causing the symptoms, but then the culprit turned out to be Celiac disease. (4) If you start using an antimicrobial treatment for assumed SIBO without any proper diagnoses, then it may cause more harm than good. So testing is essential, which can help define the treatment plan.

SIBO testing method #1: SIBO breath test

The three-hour lactulose or glucose breath test is generally used for diagnosing SIBO, which detects the different types of gases that bacteria produce in the small intestine. It checks for hydrogen and methane gas. (5) There is now a new test available in the US: the TrioSmart test that can detect the third type of gas: hydrogen sulfide. (6) I wrote about the different types of SIBO.

The bacteria in our intestines ferment specific carbohydrates, and they produce gases as a byproduct. The breath test involves drinking a sugar solution (lactulose or glucose, a type of carbohydrate) that feeds the bacteria in the gut, and they start making gases. Then these gases are absorbed in the intestines and get into our blood, from where the gases are delivered to our lungs and exhaled in our breath. That is what the breath test intended to capture.

The breath test is done for 3 hours, while breath samples are taken at 20-minute intervals. The first two hours represent the small intestine, and the last hour is usually the large intestine. Measuring the level of those gases is also important to determine how severe the bacterial overgrowth is and what treatment would suit the best.
Be aware that a prep diet is required to be followed before SIBO testing. It involves following a low-fiber diet and fasting for 14 hours. (When you order a test, you should receive instruction on the prep diet). (7)

A hydrogen breath test is also used for testing carbohydrate malabsorption issues when dietary sugars are not absorbed well, such as lactose (sugar in milk), fructose (sugar in fruit), sorbitol, and sucrose. (8)

 

Can you trust the SIBO breath tests?

While the breath test is considered the most practical SIBO testing method, it certainly has its limitations.
A meta-analysis of the breath test accuracy showed that lactulose substrate might provide a higher number of false-positive results than the glucose test. Glucose breath test seems to work better than lactulose breath test for diagnosing SIBO. It seems glucose testing has better sensitivity and specificity. (9) (10) In this case, clinicians may need to evaluate the results more carefully before giving out a diagnosis, and it would be worth doing a test for both types of substrates.

Other problems can be:
• the missing consensus on the interpretation of breath test results
• Individual’s motility can influence the test results – transit time may differ from person to person (11)

Other types of tests

If you have IBS-D or IBS-M/SIBO-D, you experience mainly diarrhea symptoms; then an IBS-SMART test is available to diagnose post-infectious IBS (PI-IBS). It is a blood test that looks for the markers of food poisoning (one of the leading causes of SIBO), which is the result of auto-antibodies forming in a lot of people and starting an auto-immune process. The antibodies measured in the blood are anti-CdtB toxin and anti-vinculin. These antibodies can attack the nerves of the gut and impair the cleaning wave, the Migrating Motor Complex. (12)(13)

What tests are not suitable to diagnose SIBO?

• Stool tests because the results represent mainly the end of the large intestine, although they might indicate some issues in the small intestine but cannot diagnose SIBO. Overgrowth of bacteria in a stool can show dysbiosis.
• Organic Acid Tests (OAT) check the urine for byproducts of yeast or bacteria in the small intestine, which can be very useful but cannot tell whether your SIBO is hydrogen/ hydrogen-sulfide or methane-dominant. (14)

Conclusions

Using SIBO testing (a breath test) has its advantages and disadvantages, but it can still be the most practical approach to diagnosing SIBO. Metanalysis showed that a glucose breath test might provide a more accurate diagnosis than a lactulose breath test. Having a SIBO diagnosis can be crucial as it can define the best treatment options (each type of gas requires different strategies).

Bear in mind that diagnosing SIBO might be just the first step because it will not tell you what caused SIBO in the first place. However, finding the underlying cause is crucial to prevent relapsing.

If you have questions regarding SIBO or need help finding out your root cause and support on your healing journey, then feel free to book a free consultation call!

 

 

* This post is only for informational purposes and not meant to diagnose or treat any disease.  I advise consulting with your healthcare practitioner regarding any treatment options or dietary changes.