What is SIBO and IMO and how can we treat it?

vitality
Sep 15
3 min read

SIBO (Small Intestinal Bacterial Overgrowth) and IMO (Intestinal Methanogen Overgrowth) are disorders related to the excessive growth of microorganisms in the small intestine. This overgrowth leads to abnormal fermentation processes and a wide range of digestive – and non-digestive – symptoms.

Although awareness of these conditions is growing, many patients still do not receive effective, comprehensive care. Symptom-focused treatment is only part of the puzzle – identifying and addressing the root cause of SIBO/IMO is key to preventing relapses and restoring full-body balance.

What Are SIBO and IMO?

SIBO is a condition where too many bacteria grow in the small intestine, where the bacterial count is normally much lower than in the large intestine.
IMO refers to the overgrowth of methanogenic archaea (e.g., Methanobrevibacter smithii), which produce methane and are often associated with constipation, bloating, and abdominal discomfort.

Although IMO was once considered a subtype of SIBO, it is now treated as a separate condition, which has important implications for both diagnosis and treatment.

Symptoms

Common symptoms of SIBO include bloating, belching, a feeling of fullness, non-specific abdominal pain, constipation (most commonly), or diarrhea.

Importantly, the symptoms of SIBO/IMO are not limited to the digestive system. Abnormal fermentation in the small intestine can impact the nervous, hormonal, immune systems, and even the skin.

Diagnosis

Diagnosis is based on a breath test, which measures levels of gases produced during the fermentation of carbohydrates by abnormal bacteria in the gut.

It’s important to use breath tests that measure both hydrogen and methane, as harmful microorganisms can produce either or both. Many commercially available tests only measure hydrogen, which can lead to false-negative results, especially in cases involving methanogens – often the cause of constipation.

The standard test lasts 2 to 3 hours (longer tests are recommended for patients with slow gastrointestinal motility or chronic constipation) and is performed after consuming a lactulose solution.

Proper interpretation of the test by an experienced practitioner is just as important as the test itself, as it forms the basis for the treatment plan.

Treatment – More Than Just Symptom Relief

SIBO/IMO therapy often includes antimicrobials to reduce excess microorganisms and support gut function. These may include medications, herbal compounds, and prokinetic agents to support intestinal motility.

However, simply managing symptoms isn’t enough. Without identifying and treating the root cause, the relief is often temporary, and relapses may occur quickly.

In addition to pharmaceutical treatment, nutrition therapy plays a key role. Creating and adjusting an individualized dietary plan with the patient is crucial for long-term success.

Lasting Results Require Root-Cause Resolution and a Holistic Approach

To effectively treat SIBO or IMO, we must address the underlying triggers. These often include:

Impaired gut motility
Stress and gut-brain axis dysfunction
Hormonal imbalances
Past surgeries or abdominal adhesions
Chronic inflammation or food sensitivities

That’s why a successful treatment plan should look at the whole body, not just the intestines.

Patients with SIBO/IMO should not be seen purely as gastroenterological cases. A broader view is needed – one that considers the interactions between body systems, hormone balance, lifestyle, stress, sleep, and physical activity.

SIBO and IMO Are Complex Conditions

Their treatment doesn’t end with prescribing antimicrobials – that’s only the beginning.

The keys to long-term success are:

Identifying and addressing the root cause
Taking a holistic approach to the patient
Developing the right pharmaceutical and nutritional strategy
Supporting lifestyle changes, including stress management, sleep, and hormone balance
Collaborating across specialties – nutrition, gastroenterology, physiotherapy, psychiatry