Intestinal Methanogen Overgrowth (IMO) Diet: A Comprehensive Guide

Are you grappling with persistent constipation, bloating, and abdominal discomfort, possibly diagnosed as irritable bowel syndrome with constipation (IBS-C)? It's possible that intestinal methanogen overgrowth (IMO) is the underlying cause. This article explores IMO, its diagnosis, and dietary strategies, including the elemental diet, to manage and potentially resolve this condition.

Understanding Intestinal Methanogen Overgrowth (IMO)

Intestinal methanogen overgrowth (IMO) occurs when methane-producing archaea, primarily Methanobrevibacter smithii, proliferate excessively in the digestive tract. This overgrowth can lead to digestive symptoms often misdiagnosed as IBS-C. IMO is a newer term that replaced methane-dominant SIBO (small intestinal bacterial overgrowth) to characterize the overgrowth of methanogens anywhere along the digestive tract. This newer terminology distinguishes two main differences between IMO and SIBO: Methanogens called archaea, not bacteria, are responsible for causing IMO and IMO can occur anywhere along the length of the digestive tract.

Signs and Symptoms of IMO

IMO, SIBO, and IBS share many symptoms:

• Abdominal pain
• Bloating and abdominal distension
• Gas
• Nausea
• Constipation and diarrhea
• Indigestion and heartburn

Methane gas, driven by methanogens like M. smithii, slows intestinal transit, contributing to constipation strongly linked to IBS-C. Malabsorption can result from IMO, potentially causing unintentional weight loss, fatigue, and fatty stools. Deficiencies in iron, vitamin B12, and vitamin D are also commonly measured on labs. Extra-intestinal symptoms are also common in the context of IMO, such as headaches, joint pain, brain fog, skin lesions, and changes in mood.

Root Causes of IMO

A breakdown in the innate protective mechanisms against archaeal overgrowth may predispose an individual to IMO. Interruptions in normal digestive enzyme production, intestinal motility, and secretory IgA can contribute to IMO. Food poisoning increases the risk of IBS by four times, and it is estimated that 80% of patients with IBS have at least one of the three SIBO subtypes. When you get food poisoning, the body produces antibodies that may affect the interstitial cells of Cajal, which help with intestinal motility. This disrupts the migrating motor complex (MMC), a vital housekeeping function that essentially acts to sweep out the bowels. An impaired MMC increases the risk for methanogens to overgrow in the intestines. Advanced age, abdominal surgery, intestinal anatomic variations, and chronic stress can interfere with normal gastrointestinal function and may increase the risk of IMO. Medical conditions that reduce mucosal immunity, slow intestinal motility, and create intestinal adhesions can contribute to methanogenic overgrowth. These may include diabetes mellitus, hypothyroidism, autoimmune diseases, colon cancer, and inflammatory bowel disease (IBD). The use of certain medications can also increase IMO risk. Chronic, frequent use of antibiotics can disrupt the normal balance of beneficial bacteria, allowing the opportunity for methanogens to overgrow. Opiates and smooth muscle relaxants may contribute to dysmotility. Proton pump inhibitors and other acid-reducing medications reduce hydrochloric acid, a natural antimicrobial digestive secretion.

Read also: Intestinal Health with Royal Canin

Diagnosing Intestinal Methanogen Overgrowth

Doctors can diagnose IMO and uncover its underlying factors using a step-wise approach.

Step 1: Breath Test

A SIBO/IMO lactulose breath test is an at-home test that measures gaseous byproducts of bacterial and methanogenic fermentation exhaled through the lungs. Due to cost and convenience, this is the most common test utilized in clinical practice to diagnose IMO. The ibs-smart panel by Gemelli Biotech measures both of these antibodies.

Step 2: Additional Testing

• Thyroid Panel: A comprehensive thyroid panel screens for hypothyroidism and thyroid autoimmunity, which can impair digestive enzyme secretions and intestinal motility. Examples of comprehensive thyroid panels that include TSH, free T3, free T4, and thyroid antibodies include: Comprehensive Thyroid Assessment by Genova Diagnostics and Comprehensive Thyroid Panel w/ Antibodies by Precision Point.
• Hemoglobin A1c (HbA1c): HbA1c is a three-month average blood sugar diagnostic for diabetes. In advanced and untreated diabetes, damage to the nerves that innervate the intestines can cause gastroparesis (slowed stomach emptying) and impaired intestinal motility.
• Imaging: Some patients may require endoscopy, colonoscopy, barium follow-through, and/or antroduodenal manometry to confirm inflammatory bowel disorders, intestinal structural anomalies, and MMC deficiencies.

Step 3: Tests to Customize IMO Management Plan

Additional functional medicine tests can help individualize management plans. Although these tests may not be indicated for every individual, they are commonly recommended by providers during a comprehensive gastrointestinal evaluation.

• Comprehensive Stool Test: A comprehensive stool test cannot diagnose IMO, but it can detect digestive enzyme deficiencies, intestinal inflammation, and large intestinal dysbiotic patterns that may contribute to or result from its presence. These are popular comprehensive stool tests ordered through Rupa Health: GI-MAP + Zonulin by Diagnostic Solutions, GI360 by Doctor's Data, and GI Effects Comprehensive Profile - 3 day by Genova Diagnostics.
• Food Sensitivities: When present in the small intestine, IMO may contribute to inflammation and a leaky gut. Increased intestinal permeability may increase the risk of food sensitivities, which can exacerbate mealtime digestive symptoms. Any of these food sensitivity panels can help personalize a therapeutic dietary plan for patients with significant food-related symptoms while IMO is being managed: Basic Food Sensitivity Panel - 96 Foods by Ayumetrix, 184 IgG Food Sensitivity Panel by Alletess Medical Laboratory, and P88-DIY Dietary Antigen Test by Precision Point.
• Cortisol Testing: A salivary cortisol test identifies maladaptive adrenal stress responses that can occur with chronic stress. Cortisol secretion imbalances can impair gastrointestinal digestive secretions and motility and often present as physical and mental fatigue and insomnia, further perpetuating the maladaptive stress cycle. When trying to assess the stress response, any one of these panels is an excellent place to start: Adrenal Stress Profile by ZRT Laboratory, Salivary Cortisol x 4 by Access Med Labs, and Adrenal Stress Panel by Ayumetrix.

Management Plan for Intestinal Methanogen Overgrowth

A successful management plan for IMO can be divided into three stages.

Step 1: Antimicrobial Therapy

The use of antibiotics is a common approach in IMO management. The goal is to reduce the intestinal methanogen population, which may contribute to the symptoms associated with this condition.

Read also: Gastrointestinal Problems in Pets: A Royal Canin Solution

• Prescription or herbal antibiotics are often used to help manage methanogen overgrowth in the gastrointestinal tract. A standard course of antibiotic therapy involves two weeks of rifaximin with either neomycin or metronidazole. Multiple courses may be required for effective management. Herbal therapy is considered effective for managing SIBO. A course of herbal antimicrobial treatment for IMO involves dosing two herbs together for six weeks. Dosing more than two herbs at once does not usually provide additional benefits. As with prescription antibiotics, multiple courses may be required for effective management. Combinations of the following botanical products can be considered for herbal IMO management protocols:
  • Allicin: 450-900 mg three times daily
  • Berberine: 500-1,500 mg three times daily
  • Emulsified Oregano Oil: 50-100 mg three times daily
  • Neem: 600 mg three times daily
• Elemental Diet (ED): The elemental diet (ED) is the only current diet with data supporting its ability to manage SIBO/IMO. The ED is considered an effective option for SIBO and IMO, with an 80% success rate after two weeks of treatment. However, the ED is unpalatable to most, and commercial formulas are expensive. Additionally, as it is a liquid-only diet, many experience emotional challenges during the treatment protocol. Patients can make their elemental formula at home or buy commercially made formulas.

Step 2: Palliative Strategies

Many patients with IMO experience digestive symptoms related to mealtimes, as methanogens ferment dietary carbohydrates, resulting in increased methane production and associated symptoms like gas, bloating, abdominal pain, and constipation.

• Nutritional modifications that limit fermentable carbohydrates can be helpful in managing digestive symptoms but are usually not effective on their own in IMO management. Therapeutic elimination diets used for symptom relief during IMO management include the low FODMAP, Specific Carbohydrate (SCD), Bi-Phasic, GAPS, and Cedars-Sinai diets.
• In addition, a prokinetic agent can be added to either herbal or pharmaceutical antimicrobial therapy to support intestinal motility. Prokinetics can assist in relieving gas and bloating symptoms. Ginger, for example, is a popular natural prokinetic that has been shown to stimulate gastric emptying when administered to patients in a dose of 1.2 grams.

Step 3: Prevention

Approximately 45% of patients experience recurrent IMO after completing antibiotic therapy. Implementing strategies to help prevent recurrence can help reduce the likelihood of rapid IMO relapse. IMO should be viewed as a symptom of another gastrointestinal imbalance. If the underlying factors of IMO are ignored, it may recur after antibiotic therapy. Given the complexity of IMO pathogenesis, this article cannot outline specific management protocols for every possible underlying factor of IMO. Using patient history and specialty labs can help determine likely factors of IMO.

The Elemental Diet for IMO: A Closer Look

The elemental diet is a liquid diet consisting of easily digestible nutrients in their most basic forms (amino acids, simple sugars, and fats). This formulation minimizes the digestive workload, starving the methanogens and allowing the gut to heal.

Case Report: Homemade Elemental Diet for IMO

One case report documented the outcome of consuming a 14-day homemade elemental diet to normalize intestinal methanogen overgrowth. The patient was a 47-year-old White female (author of this study) with confirmed IMO by the lactulose breath test (LBT). The patient treated the IMO with rounds of herbal antimicrobials and rifaximin plus neomycin periodically to maintain symptoms, while sustaining a low carbohydrate diet.

The homemade elemental diet was conducted for 14 days. The lactulose breath test results on day 15 indicated a reduction of methane levels from an average of 42 ppm to 3 ppm throughout the testing period (120 minutes). The standard prevention protocol of prokinetics, diet, and lifestyle were not effective at preventing relapse. A repeat lactulose breath test on day 122 was positive, with an average of 81 ppm methane. The elemental diet was repeated for 9 days, with fasting on day 10. The homemade elemental diet resulted in a substantial reduction in methane and symptom resolution.

Read also: Managing Intestinal Adhesions with Diet

The Homemade Elemental Diet Protocol

The homemade elemental diet was developed by Dr. The diet has 2 versions, low carbohydrate/higher fat or high carbohydrate/low fat. The low carbohydrate/higher fat version was used for this study. The ingredients were mixed with water in a blender. Calorie calculations were determined from the BMR provided through body composition analysis. Caloric intake was calculated by adjusting the BMR for an activity factor and to promote some weight loss. Protein requirements were calculated using the recommended dietary allowance (RDA) of 0.8 g/kg body weight. The elemental diet ingredients were adjusted to provide the appropriate calories and protein needed and to achieve a very low carbohydrate macronutrient level. In addition to the diet, the patient practiced intermittent fasting for 16-18 hours per day, at least 5 days per week, to stimulate the migrating motor complex (MMC).

Symptoms and Challenges

On day 2, the patient had a headache and started experiencing cold-like symptoms (sinus congestion, body aches, and fatigue). These symptoms could have been due to dehydration, so fluids were increased. Magnesium citrate was started to reduce symptoms of constipation. The fatigue started to decline after day 8. Abdominal pain, bloating, and diarrhea were variable from days 1-10, with 0 abdominal pain by day 15. Constipation was rated as a 0 by day 6. Symptoms of heartburn increased from a 1-2 (starting on day 5) to a 10 on day 10. Symptoms of vaginal burning occurred on day 10, which was suggestive of a Candida overgrowth. The patient was prescribed fluconazole, 150 mg/day for 6 days.

The psychological aspects of the elemental diet were challenging. The patient was unable to participate with family and friends during mealtime. By days 10-14, the patient felt depressed about not being able to eat. The homemade elemental formula was extremely unpalatable. The patient added orange essential oil and/or cinnamon in attempts to mask the taste. To overcome the taste, the patient would drink the formula as quickly as possible, immediately followed by teeth brushing. On days 10-14, the patient was only able to drink half of the caloric value (due to the unpalatable taste), which was consumed during the lunch hour.

Results and Relapse

The homemade elemental diet was able to normalize the LBT after 14 days, reducing methane levels from an average of 42 ppm to 3 ppm throughout the collection period. The patient lost a total of 5.4 pounds. Fat mass decreased by 1.7 pounds, dry lean mass decreased by 1.1 pounds, and total body water decreased by 2.6 pounds.

The prevention protocol was started on day 15. Week 1: The reintroduction phase was a smooth process. Stools were a 4 on the Bristol stool scale, indicating a healthy stool. Week 2: Moderate bloating returned with symptoms of anal burning. During the next few days, the patient experienced severe abdominal bloating, constipation, and abdominal pain. The patient restarted 150 mg fluconazole for 2 days and nystatin at 500 000 units was started 3 times a day. Weeks 5-6: The patient restarted nystatin and continued the prevention protocol as outlined above. Weeks 7-14: Bloating increased with small amounts of sugar and starchy food. Week 15: The patient conducted a repeat LBT. The patient restarted the elemental diet. The psychological symptoms of being on the elemental diet were more challenging the second time than the first. The patient was unable to maintain the diet past 9 days and fasted on day 10. A repeat LBT was conducted on day 11. Although the breath test was not negative, just 9 days of the elemental diet plus 1 day of fasting resulted in an average decrease of methane levels from 81 ppm to 23 ppm.

Elemental Diet vs. Antibiotics

A 3-week course of combination antibiotics (rifaximin and neomycin) improved symptoms but were not able to normalize gas levels. Patients who fail antibiotic treatment, who are unable to tolerate the treatment, or who do not have the option of a prolonged antibiotic course due to insurance coverage, can choose a 14- to 21-day elemental diet. The success of an elemental diet in normalizing LBT was published by Pimental et al. who evaluated the ability of an elemental diet to normalize the lactulose breath test LBT. In their study, 93 subjects with IBS and an abnormal LBT implemented a low-fat, elemental diet (Vivonex Plus) for 14-21 days. Eighty percent of study participants achieved a normal LBT on day 15.

Overcoming Challenges of the Elemental Diet

The elemental diet is typically used as a last resort due to poor palatability, negative psychological aspects, and potential for weight loss.

• Palatability: The taste of the homemade elemental diet was very unpleasant. In conversation with A. Siebecker, ND (February 2020) to increase palatability, it was recommended to drink the shake ice cold and to use flavorings such as Crystal Light powder and flavoring extracts. Cedars-Sinai examined whether a specialized diet could improve symptoms of gastrointestinal disorders linked to an imbalance in gut microbiota. The research tested the elemental diet’s effectiveness and explored whether improving its unappealing taste—a major barrier—could help patients adhere to the diet’s stringent protocol.
• Psychological Effects: The psychological effects caused by the inability to eat and enjoy the pleasures that food brings can be difficult to overcome. Practices such as positive thinking (e.g., “this diet is helping me heal from SIBO,” “it is only for 2 weeks”), exercising, meditation, and emphasis on self-care while on the diet is important.
• Weight Loss: Many patients with SIBO struggle with being underweight and are afraid that the diet will lead to more weight loss. Body composition measurements indicated that there was a 1.7 pound decrease in fat mass, and lean body mass only decreased by 1.1 pounds. The caloric value for this patient was used to encourage some weight loss. If calorie, protein, and fluid needs are met, weight loss should not be an issue on the elemental diet.

Preventing Recurrence

Once SIBO/IMO has been eradicated as confirmed by LBT, preventing recurrence becomes the focus.

• Diet: Diets that remove fermentable carbohydrates are useful in reducing bacterial fermentation. Carbohydrates are the most important source of fuel driving the metabolic activities of microorganisms.
• Migrating Motor Complex (MMC): Snacking in between meals is not recommended in order to stimulate the MMC. The MMC is a cleansing wave that occurs every 90-120 minutes in the fasting state. A deficiency in the MMC has been demonstrated in IBS with SIBO. This lack of motility increases the incidence of microbial colonization and a recurrence of SIBO. Unfortunately, despite the prevention protocol, the patient’s IMO relapsed within approximately 15 weeks of completing the elemental diet. The homemade elemental diet was restarted for 9 days with fasting on day 10. A significant reduction in symptoms was experienced. The patient remained on nystatin during the second round of the diet and did not experience symptoms of Candida overgrowth. Methane levels decreased but were not normalized.

Risks of Untreated IMO

The persistent overgrowth of methanogenic archaea leads to continuous methane production in the gut. Elevated methane levels are closely associated with chronic gastrointestinal symptoms that can significantly impair a patient's quality of life. Chronic constipation can lead to complications such as hemorrhoids, anal fissures, and rectal prolapse due to prolonged straining. Untreated IMO can exacerbate or contribute to the development of other functional gastrointestinal disorders, such as IBS or leaky gut syndrome. Once leaky gut has developed, toxins and undigested food particles can enter the bloodstream, potentially triggering systemic immune responses and inflammation linked to various conditions, including metabolic disorders, autoimmune diseases, rosacea, restless legs syndrome, and interstitial cystitis.

tags: #intestinal #methanogen #overgrowth #diet