According to the International Foundation for Functional Gastrointestinal Disorders (IFFGD), between 25 to 45 million people in the US experience chronic digestive issues characterized by abdominal pain, bloating, gas, and changes in bowel habits such as diarrhea and constipation.
Among these individuals, a significant portion—ranging from 50% to 78%—may actually be dealing with a condition called Small Intestinal Bacterial Overgrowth (SIBO). However, SIBO is less well-researched, leading to frequent misdiagnosis as other digestive disorders. This often results in ineffective treatments and continued discomfort.
There are five different types of SIBO, with hydrogen-dominant and methane-dominant SIBO being the most common.
This article will focus on methane-dominant SIBO, discussing its symptoms, causes, and potential treatment options. We’ll also provide a list of foods to avoid to help individuals manage their condition more effectively.
What Is Methane SIBO?
To understand methane SIBO, we must first define SIBO.
SIBO is an acronym that stands for Small Intestinal Bacterial Overgrowth. As the name suggests, it’s an increase or “overgrowth” of bacteria in the small intestine.
Unlike the large intestine (colon), which houses trillions of bacteria, the small intestine has a relatively low bacterial population. When bacteria levels increase or too many of the wrong kind end up in the small intestine, a person develops SIBO.
SIBO comes in five primary types: hydrogen-dominant SIBO, methane-dominant SIBO, hydrogen sulfide-dominant SIBO, mixed SIBO (a combination of hydrogen and methane), and SIFO (Small Intestinal Fungal Overgrowth).
Among these types, methane SIBO can be particularly challenging to treat and manage. If left without treatment, it can cause serious complications with long-term consequences.
Methane SIBO is characterized by the overproduction of methane-producing bacteria in the small intestine. The most common symptom of methane SIBO is constipation.
Methane SIBO is also known as Intestinal Methanogen Overgrowth (IMO), a term coined in 2020 by gastroenterologist Dr. Mark Pimentel and his research team. According to Dr. Pimentel, IMO is a more accurate term because:
- The methane-producing microorganisms responsible for the condition—called methanogens—aren’t considered bacteria but rather a separate group of single-celled organisms.
- Methanogens develop both in the small intestine and large intestine, so the SI (Small Intestine) in SIBO isn’t accurate.
To avoid confusion, we’ll call the condition by its original name until the new term becomes widely adopted in the professional field.
What Causes Methane SIBO?
Methane SIBO occurs when a group of microorganisms called archaea enter the small intestine via the mouth or the large intestine.
When archaea enter the mouth, they normally pass through the stomach and are pushed out of the small intestine by the Migrating Motor Complex (MMC). But when stomach acid is low and the MMC is weak, archaea can build up and cause methane SIBO.
Archaea can also enter the small intestine from the large intestine. This happens when bacteria build up and push through a weak Ileocecal Valve (ICV). A damaged or malfunctioning ICV struggles to keep bacteria and other microorganisms from flowing back into the small intestine, resulting in SIBO.
Food poisoning is the most common cause of methane SIBO. Others include:
- Traumatic brain injury
- Small intestinal dysmotility
- Disordered eating
- Thyroid imbalances (hypothyroidism)
- Coronary artery disease
- Inflammatory bowel disease
- Abdominal surgery (gastrectomy, hysterectomy, colectomy, cholecystectomy, etc.)
- Prolonged use of certain medications, such as antacids, tricyclic antidepressants, opioids, and proton pump inhibitors (PPIs)
- Diabetes
- Dyspepsia (indigestion)
- Chronic infections (parasites, Lyme)
- Endometriosis
- Pancreatitis
How to Treat Methane SIBO
Treating methane SIBO takes time and involves multiple interventions, such as medications, therapies, and dietary changes.
Typically, the initial treatment for methane SIBO is two weeks of antibiotics.
Nearly 65% of people get better with just antibiotics, but the other 45% often experience a recurrence of intestinal overgrowth. If this occurs, individuals may be prescribed another round of antibiotics as well as a two to three-week elemental diet.
Here’s a more detailed breakdown of the treatment:
Antibiotics
Antibiotics are the main treatment of methane SIBO. They’re used to reduce the population of methane-producing bacteria in the small intestine.
There are many types of antibiotics used for treatment, and specific types depend on individual circumstances.
Methanogenic archaea are resistant to most antibiotics used against bacteria, so doctors typically recommend a combination of Rifaximin (Xifaxan) and Neomycin to fight these methane-producing microorganisms. Together, these medications have a success rate of up to 87%, as opposed to only a 30% success rate of Rifaximin by itself.
Unfortunately, there are quite a few side effects of using Neomycin to treat methane SIBO. Since Neomycin is a broad-spectrum antibiotic, it’s known to damage the microbiome and permanently reduce the population of beneficial bacteria.
Research also found that Neomycin disturbs the intestinal membrane, potentially worsening pre-existing conditions of the gut.
So while the Rifaximin + Neomycin combo is extremely effective in treating methane SIBO, the risks associated are a lot worse. Therefore, physicians carefully weigh the pros and cons of these medications before prescribing them to the patient.
More often than not, doctors prescribe Rifaximin because it’s low-risk. But since the success rate is so minimal, recurrence is common.
Methane SIBO Diet
Alongside medication, physicians often recommend patients take a strict methane SIBO diet. The goal of this diet is to manage and minimize the symptoms of methane SIBO as the patient undergoes treatment.
The methane SIBO diet is much like the diet prescribed to those with IBS since both disorders have relatively similar symptoms.
The methane SIBO diet includes a number of practices, with the most common being low-FODMAP Diet and Elemental Diet. It also includes taking supplements like probiotics, prebiotics, and promotility agents.
Low-FODMAP Diet
Low-FODMAP diet restricts carbohydrates known as FODMAPs. FODMAP stands for:
- F – Fermentable
- O – Oligosaccharides
- D – Disaccharides
- M – Monosaccharides
- A – And
- R – Polyols
FODMAPs are sugars that are poorly absorbed in the small intestine, leading to digestive issues and symptoms like diarrhea, constipation, abdominal pain, and bloating.
Eliminating or reducing FODMAPs in one’s diet can offer relief from these symptoms. People on this diet avoid a list of specific fruits, vegetables, dairy products, and grains, like apples, beans, bread, pasta, milk, yogurt, and foods with high fructose corn syrup and artificial sweeteners.
We’ll go into more detail about what to avoid in the upcoming sections.
Elemental Diet
Elemental diet is a highly restrictive liquid-only diet. It replaces foods and drinks with special formulas and nutrients in a “predigested” form. The liquid is made up of various compounds, including mono/disaccharides, medium-chain triglycerides, and amino acids. It’s also supplemented with minerals, vitamins, and trace elements.
Elemental diet usually lasts between two to six weeks, depending on the severity of the condition. It’s one of the most effective treatments of SIBO when followed correctly, but it isn’t the easiest to maintain and can be quite expensive as well.
Herbal Antimicrobials
Herbal antimicrobials are another effective treatment for methane SIBO. They’re a lot less aggressive than antibiotics, so there’s a lower risk of harmful side effects. They’re also believed to be just as effective as antibiotics in clinical trials.
Healthcare professionals use a combination of herbal antimicrobials to treat methane SIBO. Among the most common include:
- Allicin: A natural antibiotic with antiviral and antifungal properties. Though it’s commonly found in garlic (a high FODMAP food), it doesn’t contain high fructo-oligosaccharides that trigger SIBO symptoms.
- Oregano: Oregano oil eliminates or at the very least inhibits the growth of intestinal microbes without damaging the gut. Like allicin, it has antifungal, antimicrobial, and antiviral properties.
- Berberine: Extracted from goldenseal, Oregon grape, and barberry plants, berberine inhibits the growth of harmful bacteria in the gut and strengthens the gut lining. It can also reduce inflammation, a common side effect of methane SIBO.
- Neem seed oil: Thanks to its antimicrobial and anti-inflammatory properties, neem oil can be effective in managing SIBO symptoms and reducing harmful gut bacteria.
- Atrantril: Atrantril is an herbal supplement that disrupts methane production in the small intestine. It moves the unwanted bacteria from the small intestine to the large intestine, allowing the body to expel gas more effectively.
Supplements
As of the time of writing, there’s limited and conflicting evidence regarding the intake of supplements—particularly prebiotics and probiotics—in the treatment of methane SIBO.
Some research suggests them to be beneficial, while others are believed to worsen symptoms and even increase methane production.
As with antibiotics, physicians need to carefully consider the health and condition of the patient before recommending supplements to treat methane SIBO.
Prebiotics
According to research, prebiotics like Partially Hydrolyzed Guar Gum (PHGG) and Galacto-oligosaccharides (GOS) have been shown to reduce methane levels.
Both prebiotics have been found to increase the population of beneficial bacteria like Bifidobacteria and Lactobacillus, which can help to reduce methane production.
However, the effectiveness of these prebiotics can vary from person to person. Some SIBO sufferers negatively react to prebiotics, so it’s important that they’re introduced slowly and systematically. If adverse effects are seen, treatment must be halted immediately.
Probiotics
Certain strains of probiotics, such as Bifidobacterium lactis and Lactobacillus reuteri, reduce methane levels in the body and alleviate SIBO symptoms like bloating, discomfort, and constipation.
The problem with probiotics, however, is that some strains—like the Bifidobacterium infantis—can actually increase methane production.
As with prebiotics, physicians need to find the right strains for the right client with the right quantity. The wrong strain or quantity can worsen the symptoms.
Promotility Agents
Promotility agents, also known as prokinetic agents, are medications that stimulate the muscles in the digestive tract. They contract the digestive tract more forcefully and frequently, helping food move through the intestines more easily.
Promotility agents aren’t as high risk as prebiotics or probiotics and are generally considered safe when taken correctly. These medications encourage daily bowel movements, which is essential for treating methane SIBO and preventing relapse.
Medications include:
- Bethanechol
- Metoclopramide
- Domperidone
- Cisapride
Lifestyle Changes
As with most conditions, the right lifestyle changes can significantly reduce symptoms and improve quality of life.
Simple changes like reducing stress and getting a full night’s sleep can help treat SIBO.
Moreover, studies suggest that stimulating the nervous system through vagus nerve exercises can manage symptoms of methane SIBO. Here are some examples of vagus exercises:
- Diaphragmatic breathing (also known as deep breathing)
- Meditation
- Cold water exposure/immersion
- Activating muscles in the throat through humming, singing, or gargling
- Physical exercise like interval training and endurance training
- Massage in the head and neck area
Foods to Avoid With Methane SIBO
Unlike certain medical conditions that restrict specific categories of food, the optimal diet for managing methane SIBO can vary significantly from person to person.
Therefore, people suffering from methane SIBO must track what they eat and log their symptoms and their severity. Dietitians specializing in digestive health can create a suitable diet with the logged information while the patient undergoes treatment.
That said, there are some “trigger” foods to avoid with methane SIBO. These foods are called high-FODMAP foods.
High-FODMAP foods are a group of short-chain carbohydrates that the small intestine absorbs poorly. As these foods ferment in the gut, they produce excess methane gas and cause bloating, distention, constipation, and other SIBO symptoms
Here’s a list of high-FODMAP foods to avoid with methane SIBO:
Dairy Products (high in lactose)
- Yogurt
- Milk
- Cheese
- Icecream
- Soft cheeses
Certain Fruits (high in fructose and polyols)
- Apples
- Pears
- Mangoes
- Watermelon
- Stone fruits (peaches, plums, cherries)
- Avocado
Certain Vegetables (high in fructans)
- Asparagus
- Garlic
- Onions
- Chicory
Wheat and Rye Products (high in fructans)
- Wheat
- Rye
- Barley
Legumes and Pulses (high in Oligosaccharides)
- Chickpeas
- Beans
- Lentils
- Soybeans
Sweeteners
- Sorbitol
- Xylitol
- Mannitol
- Honey
- High-fructose corn syrup
For those struggling with SIBO, managing a low-FODMAP diet can be challenging. SIBO meal delivery services can be a helpful resource in maintaining dietary restrictions while ensuring you get balanced, nutritious meals.
The goal of a low-FODMAP diet isn’t to permanently eliminate FODMAPs but to identify specific intolerances and adjust the diet accordingly. Meal delivery services can support this process by offering convenience and consistency, allowing you to focus on identifying and managing your personal sensitivities.
Symptoms of Methane SIBO
The symptoms of methane SIBO are similar to IBS, which is why methane SIBO is often misdiagnosed as the former.
Research found that as much as 78% of people suffering from IBS have SIBO, making IBS a common symptom of this condition. Other symptoms include:
- Distention
- Abdominal pain
- Constipation
- Diarrhea
- Flatulence
- Bloating
- Unexplained weight gain
Bloating and distension are the most noticeable symptoms of methane SIBO and are a telling difference from hydrogen-dominant SIBO.
Hydrogen SIBO doesn’t cause bloating because it reduces the total gas volume in the gut, while methane SIBO increases it. This is because methane production is associated with slower gut transit time, meaning food moves through the digestive system more slowly. Slower gut transit time allows gas to accumulate, leading to bloating.
Methane is also believed to interfere with nutrient absorption, which can exacerbate bloating and digestive issues.
FAQs
Can You Treat Methane SIBO With Diet Alone?
Considering the risks associated with antibiotics, supplements, and certain medications in the treatment of methane SIBO, it’s reasonable to hope that methane SIBO can be treated with dietary changes alone.
Unfortunately, that isn’t the case.
Once methane-producing microbes enter the small intestine, they’ll continue to grow and cause problems until they’re removed with antibiotics or herbal antimicrobials. Effective treatment of methane SIBO requires a combination of medication, diet changes, and lifestyle changes.
How Is Methane SIBO Different From Hydrogen SIBO?
The primary difference between methane SIBO and hydrogen SIBO is that the former is caused by the methane-producing microorganism Methanobrevibacter smithii while hydrogen SIBO is caused by hydrogen-producing bacteria like Escherichia coli, Streptococcus, Clostridium, and Bacteroides, among others.
The most common symptom of hydrogen SIBO is diarrhea, as opposed to constipation seen in methane SIBO.
The best way to test whether a person has methane or hydrogen SIBO is through a breath test. If a patient has elevated levels of hydrogen, it’s an indication that they have hydrogen SIBO. If a patient has elevated levels of both hydrogen and methane, it means that they have mixed SIBO (both methane and hydrogen SIBO).
Can I Eat Dairy Products If I Have Methane SIBO?
There’s no one-size-fits-all answer to this question. Some people experience no adverse effects with dairy products, while others find them problematic.
Generally, though, physicians often recommend against consuming dairy products because they contain lactose.
More than 65% of adults are lactose intolerant and experience symptoms like bloating, gas, and diarrhea when consuming high-lactose foods. These symptoms can be exacerbated in individuals with SIBO.
