Digestive issues and gastrointestinal disorders can make everyday activities a troublesome experience for some people. These individuals may occasionally experience digestive problems, such as bloating and constipation, or some might encounter these issues on a daily basis. Small intestinal bacterial overgrowth (SIBO) is a condition that includes methane-dominant SIBO—also known as intestinal methanogen overgrowth (IMO)—hydrogen-dominant SIBO, and hydrogen-sulfide SIBO. It is possible for someone to have multiple types of SIBO at the same time. Here are important details on what SIBO is, its causes, types, and treatment options.

What is SIBO?

SIBO is a condition that is characterized by an overgrowth of bacteria in the small intestine, which is meant to be relatively sterile. Most of the healthy intestinal bacteria should be localized in the large intestine (colon). When an individual consumes carbohydrates, bacterial fermentation occurs and gas is produced. As a result, they may feel bloated, constipated, or excessively gassy. These symptoms tend to be exacerbated by eating, and it is challenging to pinpoint specific foods as problematic because so many foods can worsen SIBO symptoms. People with SIBO may also experience abdominal pain and diarrhea. Additional symptoms may include headaches, fatigue, joint pain, weight loss, and rashes on the skin.

Causes of SIBO

To effectively treat SIBO, it’s important to understand the potential causes of this medical condition. Here are some possible causes of SIBO:

• Diet
• Medications, such as antacids and antibiotics
• Chronic stress 
• Digestive tract inflammation (celiac, IBD)
• Intestinal hernia or scar tissue
• Abdominal surgery
• Small intestine and large intestine connector valve issues
• Gastroparesis
• Inadequate stomach acid levels

How Do Methane and Hydrogen SIBO Differ?

Hydrogen SIBO occurs when bacterial overgrowth produces hydrogen. In methane-dominant SIBO, the bacteria produce methane gas. The different types of gas production are a result of different species of bacteria. In addition to the different gases the bacteria produce, the symptoms may also vary between the two SIBO conditions.

Methane vs. Hydrogen SIBO Symptoms

Hydrogen SIBO and methane SIBO tend to produce different symptom patterns; however, keep in mind that each individual may present differently in their symptoms. Individuals who experience hydrogen SIBO will often present with more diarrhea and abdominal pain, whereas those who suffer from methane SIBO tend to experience bloating, constipation, and gas. It is possible for some people to experience both hydrogen SIBO and methane SIBO conditions, and may have a mix of all of these symptoms.

Methane SIBO / IMO vs. IBS-C

Methane SIBO (also called intestinal methanogen overgrowth, or IMO) presents very similarly to irritable bowel syndrome with constipation (IBS-C). Since methane slows digestion, constipation and bloating are common in both conditions. Because IBS is often considered a diagnosis of exclusion—there is no “positive” test for IBS, only the absence of findings on other tests—misdiagnosis can happen if SIBO testing is not included in the evaluation. This means some people who are told they have IBS-C may actually have SIBO, or they may have both conditions at the same time. For this reason, it is important to rule out SIBO as a possibility whenever IBS-C is suspected, since appropriate testing and treatment can significantly change outcomes.

Testing for Methane SIBO

Before starting treatment, it’s important to confirm whether methane SIBO (IMO) is present. The most common method is a breath test, which measures hydrogen and methane levels after drinking a sugar solution such as lactulose or glucose. Elevated methane levels on a breath test can indicate IMO. Because symptoms of methane SIBO and IBS-C overlap, testing helps clarify the diagnosis and ensures treatment is directed appropriately. A healthcare provider may also review your medical history, risk factors, and response to previous treatments when determining whether SIBO testing is appropriate.

Common Methane SIBO Treatments

There are several commonly used treatments for methane SIBO, ranging from medications to lifestyle modifications. Here are some ways medical professionals might recommend treating methane SIBO:

Medications

One of the top prescribed medications for methane SIBO treatment is antibiotics. The antibiotic rifaximin may be prescribed on its own or in combination with neomycin. It’s essential to note that neomycin may kill more than just the bacteria related to SIBO. In contrast, rifaximin doesn’t cause as much damage to beneficial bacteria; however, rifaximin alone is generally not an adequate treatment for SIBO (IMO). You can also combine rifaximin with herbal supplements like allicin.

Methane SIBO Diet

Your doctor or dietitian may recommend following a specific diet to help manage methane SIBO. This diet plan uses nutrition along with medications to reduce symptoms. There is not much concrete evidence related to managing methane SIBO through diet, as the research was often conducted on those who experienced IBS. However, experts have found success clinically with using certain diets. Many utilize a low-FODMAP diet—a plan that restricts FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols)—when dealing with methane SIBO. This diet is more effective for symptom management than actual treatment. Other dietary approaches aimed at managing symptoms and preventing recurrence involve limiting or avoiding specific foods that are known to increase risk for SIBO, or, in certain cases, using an elemental diet. Working with a SIBO dietitian can provide assurance that you’re making productive and beneficial changes to your diet as you work toward treating methane SIBO.

Supplements

Supplements are another treatment method that may be prescribed for methane SIBO. Some supplements that may be recommended to reduce methane SIBO symptoms include probiotics, prebiotics, herbal antimicrobials, and pro-motility agents. However, it is important that only specific types of probiotics are utilized during treatment, and prebiotics are not used during treatment—only after. It is essential to discuss the use of supplements with your doctor or dietitian before taking any of these items. 

Lifestyle

Lifestyle changes such as reducing stress, improving sleep habits, and physical activity may help alleviate or reduce risk for methane SIBO symptoms. Additionally, nervous system adjustments such as vagus nerve activation can aid in symptom relief and gut motility.

How Long Does Methane SIBO Treatment Take?

The length of time it takes to treat methane SIBO varies. Initially, your doctor might prescribe a round of antibiotics. Some individuals may require multiple rounds of treatment, depending on the severity of the overgrowth. Dietary restrictions or an elemental diet may also be considered throughout the treatment course. Ideally, sustainable, long-term dietary changes would be made to reduce the risk of recurrence.

Work With a Dietitian and Treat SIBO

Anyone experiencing SIBO symptoms would benefit from working with a dietitian to help manage their condition and alleviate symptoms. A dietitian can provide guidance and create meal plans to help reduce symptoms and get you feeling better soon.

Book a SIBO Dietitian Appointment

Don’t suffer with methane SIBO longer than you have to! Book an appointment with a SIBO dietitian and discover how they can help alleviate your symptoms and reduce risk of recurrence, allowing you to return to optimal health without SIBO-related issues impacting your daily life.