Methane gas slows transit time while hydrogen speeds it up. While methane is associated with constipation, hydrogen gas produced in excess with SIBO is associated with diarrhea. So, the name Intestinal Methanogen Overgrowth is really more fitting. Methanogens produce methane gas and can overgrow in the small bowel (intestine) or the colon (large intestine). Many GI doctors are not very familiar with SIBO, IMO, or breath testing, so make sure you find either a doctor of nutritionist who doesn’t dismiss your symptoms or deny you the testing you request. A breath test is the only way to accurately diagnose SIBO. Note that you cannot accurately diagnose SIBO via a stool test, though there are markers on a stool test that can indicate SIBO. (speaking from experience via the clients with whom I work). You’ll need a qualified practitioner to interpret the results for you, but it can be such a relief to find out what’s causing your uncomfortable symptoms after years of hearing doctors say they don’t know why you have IBS. It’s the Small Intestinal Bacterial Overgrowth 3-Hr Lactulose test. You can order your own breath test (a kit that comes to your house and that you can do at home) via this link. If you’ve been diagnosed with IBS, please get tested for SIBO. Often when people have SIBO or IMO, their first diagnosis will be Irritable Bowel Syndrome (IBS), which is really a fancy way of saying ‘we don’t know what’s wrong with your gut.’ Up to 80 percent of IBS cases are actually SIBO. We also now know that methanogens can be present throughout the intestinal tract, both small and large intestine, and not just isolated to the small intestine like SIBO. The B in SIBO stands for bacteria, and methanogens are typically not bacteria they’re actually archaea. IMO was previously known as methane dominant SIBO (small intestine bacterial overgrowth), but the more we learn about SIBO, the more we understood the name, methane dominant SIBO, was not really accurate. Here’s all the info you need to treat IMO.

You can relieve the bloating and rebalance your gut with changes to your diet and by killing the excess methanogens which will eventually restore regularity. If you are struggling with constipation and look 6 months pregnant with belly bloat by the end of the day, you could have intestinal methanogen overgrowth (IMO).

Small bowel intestinal overgrowth