Small Intestinal Bacterial Overgrowth (SIBO)
Excess bacteria in the small intestine that ferment foods early, injure the lining and derail the gut’s microbial balance.
Overview
SIBO occurs when too many bacteria — or the wrong types — overgrow in the small intestine. Unlike the large intestine, the small intestine normally contains only small amounts of bacteria. Overgrowth can interfere with nutrient absorption and cause a range of digestive and systemic symptoms.
Studies suggest SIBO may be present in up to 60–80 % of people with IBS-like symptoms (gut.bmj.com).
Common Misunderstandings
SIBO is often misunderstood or misdiagnosed. Some patients are told their symptoms are purely functional (stress-related), yet SIBO can be a physiological issue involving impaired motility, structural changes, or altered gut defences. People often go through years of restrictive diets or repeated courses of antibiotics without lasting relief.
How is SIBO Linked to Your Microbiome?
SIBO represents a direct microbiome imbalance in the small intestine.
- Overgrowth can include both normally harmless large intestine bacteria and potentially harmful species (nature.com).
- The methane-producing microbe Methanobrevibacter smithii is often linked to constipation-predominant SIBO, while hydrogen-producing species may be associated with diarrhoea (gut.bmj.com).
- SIBO can develop after food poisoning, surgery, chronic acid suppression, or conditions affecting gut movement.
- Eradication or reduction of overgrowth — using antibiotics or herbal antimicrobials — often leads to improved symptoms, but recurrence is common without addressing underlying causes.
Symptoms
Bloating or abdominal distension
Often worse after meals.
Excess wind or belching
Loose stools
Constipation
Alternating stool patterns
Jumping between constipation and diarrhoea.
Abdominal discomfort or cramping
Fatigue
Brain fog
Nutrient deficiencies
The Microbiome Clinic™
Our treatment approach for SIBO includes:
Breath Test
The SIBO Breath Test identifies the presence of hydrogen and/or methane in the breath — byproducts indicative of SIBO.
Microbiome Test
Profile the gut to identify dysbiosis that may be affecting symptoms or treatment using the Gut Microbiome Test.
Targeted Antimicrobial Strategies
Antibiotics + Plant-based or pharmaceutical antimicrobials, where appropriate.
Nutritional and Motility Support
Nutrition strategies to support recovery and enhance your overall health such as a tailored low-FODMAP diet or fibre consumptions strategies.
Probiotics and Prebiotics
Targeted probiotics and prebiotics are introduced slowly to restore balance and biodiversity of microbes in the gut without fuelling overgrowth.
Suspect you might have SIBO?
