IMO – diet, causes, and symptoms
IMO refers to a specific type of microbial overgrowth in the gut that disrupts the digestive system. Once known as methane-based SIBO, it can cause constipation, bloating, and may contribute to weight gain. This clinical condition is typically diagnosed through a breath test. What is IMO, and what are its symptoms? What kind of diet can support individuals dealing with archaeon overgrowth? How can we ensure good gut health?
Table of contents
- What is IMO?
- What are archaea?
- Causes of IMO
- Is SIBO a cause of IMO?
- Other conditions linked to IMO
- Symptoms of IMO
- Extra-gastrointestinal symptoms of IMO
- How to diagnose IMO? Key methods and their effectiveness
- Other diagnostic methods for IMO
- Diet for IMO - what to eat and what to avoid?
- Can IMO be cured?
- Complications of Untreated IMO - what you should know!
- Herbs and supplements - supporting IMO treatment
- IMO disease - conclusion
What is IMO?
IMO (Intestinal Methanogen Overgrowth) is a condition characterized by the overgrowth of methanogens in the gut. Prior to 2020, it was referred to as methane-based SIBO. Since IMO involves the overgrowth of archaea in the gut, which are microorganisms capable of producing methane, it has since been recognized as a distinct medical condition.
IMO is a clinical condition marked by excessive methane production in the gut and colon, which can lead to various undesirable symptoms and digestive issues.
What are archaea?
To better understand what IMO means, it's important to know what methanogens are. Archaea are microorganisms first described in 1977. These microbes, found in soil and aquatic environments, are also a natural component of the human microbiome. They are single-celled organisms without a nucleus, with distinctive outer structures that allow them to form larger groups. Methanogens play a role in maintaining gas homeostasis in the gut and may help eliminate excess hydrogen from the intestines.
Studies indicate that archaea can be found in the human mouth, gut, skin, and reproductive tract. They are particularly common among adults and seniors. The most prevalent methanogen in the human body is Methanobrevibacter smithii, which is present in nearly all patients with IMO. Less commonly, Methanosphaera stadtmanae is also found.
SIBO (Small Intestinal Bacterial Overgrowth) refers to an overgrowth of bacteria in the small intestine. Until recently, excessive methane production in the human body was classified as a type of SIBO (methane-SIBO). However, this was deemed insufficient, as SIBO involves bacterial overgrowth, while IMO is associated with archaeal overgrowth. As such, IMO is now defined as an overgrowth of methanogens, distinct from bacterial overgrowth.
Causes of IMO
Archaea can naturally inhabit the bodies of healthy individuals, so their presence in the gut isn't inherently problematic. However, an overgrowth of methanogens may disrupt digestive function and lead to undesirable symptoms.
The overgrowth of methanogens is typically prevented by protective mechanisms in the body. If these mechanisms are impaired, the risk of IMO increases.
A slow gut motility may contribute to the development of IMO. Since archaea are slow metabolizers, they require a long time to complete metabolic processes. Therefore, reduced motility can promote archaeal growth, while faster gut movement can lower the chances of IMO. Additionally, bile acids, which are known to inhibit methanogenesis, play a role in regulating methanogen activity. Proper bile circulation may thus reduce the risk of IMO, while disruptions in bile flow may contribute to archaeal overgrowth.
Is SIBO a cause of IMO?
Methanogens require hydrogen for methane production, as the process of methanogenesis depends on the utilization of four hydrogen molecules. Hydrogen synthesis occurs during carbohydrate fermentation in the small intestine, which is carried out by bacteria.
An excess of bacteria in the small intestine (SIBO) can lead to increased hydrogen production, promoting methanogenesis and methanogen overgrowth. For this reason, patients with SIBO often exhibit concurrent IMO.
Other conditions linked to IMO
While disruptions in gut defense mechanisms are the primary causes of methanogen overgrowth, other conditions and diseases may also contribute to IMO. Individuals with irritable bowel syndrome (IBS) with constipation or chronic pseudo-obstruction are at higher risk for archaeal overgrowth. Other factors that may influence IMO include:
- chronic stress
- poor environmental conditions
- advanced age
- long-term use of proton pump inhibitors (PPIs)
- anatomical abnormalities in the gut
- Helicobacter pylori infection
Certain diseases may predispose individuals to IMO, including:
- celiac disease
- Crohn’s disease
- inflammatory bowel diseases
- autoimmune diseases
- diabetes
- pancreatic insufficiency
Symptoms of IMO
Patients with IMO commonly report digestive-related symptoms. The most frequent symptoms of archaeal overgrowth in the gut include:
- constipation, as methane can slow gut transit;
- bloating and gas, often accompanied by constipation, causing discomfort and a feeling of fullness in the lower abdomen.
Other symptoms that may appear include:
- abdominal pain
- weight gain
- lower resting heart rate
- fullness in the abdomen
Extra-gastrointestinal symptoms of IMO
In some cases, methanogen overgrowth in the gut may cause symptoms outside the digestive system. Patients with IMO may experience:
- skin changes
- mood swings
- fatigue
- anxiety related to eating
- increased hair and nail brittleness, often due to nutrient deficiencies
How to diagnose IMO? Key methods and their effectiveness
There are several methods for diagnosing archaeal overgrowth in the gut, but the most commonly used is the hydrogen breath test (HBT), specifically the hydrogen-methane breath test (HMBT), which is non-invasive and affordable.
The hydrogen-methane breath test relies on the fact that human cells do not produce methane or hydrogen. Proper fermentation of nutrients should result in complete absorption of gases produced by bacteria and archaea in the small intestine. The presence of these gases in exhaled air indicates excessive gas production and a disruption in the body’s normal processes.
In digestive system diagnostics, the hydrogen breath test is often used to detect bacterial overgrowth in the small intestine (SIBO). However, to diagnose IMO caused by methanogen overgrowth, a hydrogen-methane breath test is needed to detect methane in the breath, indicating archaeal overgrowth.
Other diagnostic methods for IMO
Other less commonly used diagnostic methods include:
- Small intestine aspirate testing, an invasive procedure requiring gastroscopy;
- Endoscopy, another invasive method that involves inserting a fiber-optic tube into the digestive system.
Diet for IMO - what to eat and what to avoid?
In the treatment of IMO, as with SIBO, a low-FODMAP diet is recommended. This diet is low in fermentable carbohydrates, which reduces the production of substrates used by bacteria and, subsequently, by archaea.
The low-FODMAP diet includes meat, nuts, seeds, and certain fruits and vegetables, as well as lactose-free dairy products and grains made from rice, oats, corn, or spelt flour. Wheat products, traditional dairy, certain fruits and vegetables, and dry legumes should be avoided. Cashews, pistachios, and sweeteners like maltitol or xylitol are also restricted.
In some cases, a specific carbohydrate diet (SCD) or the Siebecker protocol may be helpful for managing IMO.
Can IMO be cured?
Although antibiotic therapy, herbal treatments, and the low-FODMAP diet can improve symptoms and quality of life, many patients experience a relapse soon after finishing treatment. This is because antibiotics primarily target archaeal overgrowth, not the underlying cause of IMO.
For IMO treatment to be effective, the primary focus should be on identifying and addressing the root cause of the condition, followed by symptom management to alleviate the effects of archaeal overgrowth.
Complications of Untreated IMO - what you should know!
While the treatment process for IMO is time-consuming and challenging, archaeal overgrowth in the gut should not be overlooked. Untreated IMO can lead to chronic, multi-system consequences, increasing the risk of developing:
- anemia
- nutrient deficiencies
- immune and hormonal system dysfunctions
- leaky gut syndrome
Additionally, untreated IMO may contribute to increased inflammation and the development of Crohn’s disease, while immune and hormonal imbalances can result in higher susceptibility to infections, menstrual disorders, and infertility.
Herbs and supplements - supporting IMO treatment
Research indicates that probiotics containing Lactobacillus reuteri strains may help alleviate IMO symptoms. Additionally, prokinetic agents, which improve gut motility, can be beneficial. These may include pharmaceutical substances as well as natural ingredients like ginger and artichoke.
Some commonly recommended herbs and supplements for supporting IMO treatment include:
- Allicin, derived from garlic, which has antibacterial, antifungal, and antioxidant properties,
- Psyllium husk, which may help relieve bloating, abdominal pain, and constipation, promoting regular bowel movements,
- Berberine, known for its anti-inflammatory properties and positive effects on the gut microbiome,
- Oregano oil, which may aid bile flow, reduce bloating, and act as an antibacterial,
- Ginger root, which can reduce gut inflammation and support mucosal regeneration.
IMO disease - conclusion
IMO is an overgrowth of methanogens in the gut, often manifesting as constipation, bloating, and gas. This condition, caused by disruptions in digestive system defense mechanisms, is typically diagnosed using methane-hydrogen breath tests. The most effective treatment for IMO includes antibiotics, but attention to helpful herbs, supplements, and a low-FODMAP diet is also essential in managing the condition.
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