How Do I Know If I Have SIBO?

by | September 19, 2021 | Articles, Gut Health

What is SIBO?

SIBO stands for small intestinal bacterial overgrowth. It is a condition whereby certain types of bacteria, those that produce hydrogen gas, overgrow in the small intestine, thereby causing a constellation of symptoms.

What is IMO?

IMO stands for intestinal methanogenic overgrowth – a condition whereby methane-producing archaea are present in the intestine, and cause symptoms associated with excess methane gas production. These organisms are distinct from bacteria, which is why their overgrowth is classified as IMO (even though they are often referred to as a type of small intestinal bacterial overgrowth (SIBO) with methane overgrowth).

What Symptoms are Caused by SIBO, IMO and Excess Hydrogen Sulfide Gas?

SIBO symptoms can be quite debilitating. Small intestinal bacterial overgrowth (SIBO) can cause bloating, gas, belching, abdominal discomfort, abdominal pain, nausea and can be associated with constipation or diarrhea. While IMO presents with most of the same symptoms noted above, it is associated with constipation. Hydrogen sulfide SIBO, a rare form of SIBO, is associated with diarrhea and foul-smelling gas. Gastrointestinal symptoms occur after eating, and individuals who have SIBO have a hard time finding foods that do not exacerbate their symptoms. Because of the nature of SIBO and IMO, I often hear from my patients that it is when they try to eat healthy, that their gastrointestinal symptoms get worse. This often prevents people from being able to maintain a healthy diet, rich in plants, but also prevents them from dining out, planning social events, as they don’t know when or how severely their symptoms will act up. 

What Other Health Problems Can I Experience if I Have SIBO?

If severe, SIBO and IMO can affect the absorption of nutrients, and thereby increase the risk of nutrient deficiencies, such as vitamin B12, thiamin, niacin and iron deficiencies. SIBO has also been linked to leaky gut or increased intestinal permeability. As a result, SIBO has been associated with rashes, mood symptoms, fatigue, brain fog, joint aches and autoimmunity. Dr. Allison Siebecker discusses additional symptoms that can be present from hydrogen sulfide SIBO here.

What Causes SIBO?

There are a number of predisposing factors that may lead to overgrowth of bacteria in the small intestine. These include pancreatic insufficiency, prior gastrointestinal surgery, impaired motility of the gastrointestinal tract (may be caused by medications such as benzodiazepines or opioids), achlorhydria/hypochlorhydria/low stomach acid (often caused by medications such as proton pump inhibitors, which are used to treat acid-reflux, but can also be due to autoimmunity, H pylori infection, hypothyroidism, or other causes such as gastric cancer), structural abnormalities, Celiac disease, scleroderma, alcoholism, or other conditions. 

How Can I Get Tested for SIBO and IMO?

The test to determine whether you have excess gas production is a lactulose (or glucose) breath test. This test involves drinking a lactulose (or glucose) solution and providing breath samples by delivering breaths into an inflatable bag at baseline (prior to drinking the solution), and at intervals of 20, then 30 minutes, over 2 or 3 hours, depending on the test. As it passes through the small intestine, lactulose is fermented by the bacteria that are present, which then produce hydrogen or methane gases as byproducts. Lactulose is not absorbed by the body and typically passes from the mouth to the large intestine in 90 minutes, but this can vary. The 3-hour breath test should be ordered for individuals if there is a concern of slower intestinal transit, as this reduces the risk of a falsely negative test. The gases are excreted in the breath.

How Do I Prepare For a SIBO Breath Test?

It is important to note that you will be required to eat a limited diet prior to taking the test and that it is advised that you be off of certain medications (such as laxatives and antibiotics) and supplements (such as antimicrobial herbs) prior to the test. Always check with your doctor if it is advisable for you to hold medications and/or supplements for the test. It is important to review the preparation instructions provided by the lab analyzing the test. In the 24 hours prior to the test, you are only allowed to eat baked or broiled chicken, fish or turkey (salt and pepper only), white bread (only), plain steamed white rice, eggs, clear chicken or beef broth (no vegetable pieces). For beverages, you may have water, plain coffee and tea. You are required to fast for 12 hours before the test. You may drink water during your fast.

The test kit can be shipped to a person’s home upon a healthcare professional’s order. For those individuals who experience diarrhea, it may be helpful to do the trio smart test, to determine whether a different form of small intestinal bacterial overgrowth (SIBO), which involves excess hydrogen sulfide, is present.

What Do My Test Results Mean?

The criteria for diagnosis of SIBO according to the North American Consensus published in 2017 are:

Hydrogen gas increase from baseline by >= 20 ppm (parts per million) over the course of the first 90 minutes from ingestion of lactulose (or glucose). This is considered a positive test.

IMO is present if methane gas peaks at >= 10 ppm at any time from ingestion of lactulose (or glucose). 

To read about integrative medicine treatment options for SIBO and IMO, continue here.

If you live in NY, CA, CT or NJ and have documented SIBO or have symptoms of it, including bloating, gas, nausea, abdominal pain or discomfort, diarrhea, or constipation, call our practice at 646.627.8000 or contact us here for a complimentary discovery call with Dr. Bojana Jankovic Weatherly. We can go over some of your questions, such as how we treat SIBO, over the phone. Our team looks forward to helping you get your health back on track!


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