SIBO vs Irritable Bowel Syndrome: Key Differences So You Don’t Confuse Them
Small Intestinal Bacterial Overgrowth (SIBO) and Irritable Bowel Syndrome (IBS) can cause very similar digestive symptoms — like bloating, gas, abdominal discomfort, and irregular bowel habits — which is why they are often confused. However, they are distinct conditions with important differences that matter for diagnosis and treatment. Entender sus diferencias evita frustraciones y tratamientos ineficaces
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What Is SIBO?
SIBO happens when there’s an excess of bacteria in the small intestine, where normally only a small number of microbes belong. This can interfere with digestion and nutrient absorption.
What Is IBS?
IBS is a functional gastrointestinal disorder defined by chronic abdominal pain, bloating, and changes in bowel habits (diarrhea, constipation, or both) without an identifiable structural cause.
Key Differences Between SIBO and IBS
1. Underlying Cause
SIBO: A measurable overgrowth of bacteria in the small intestine.
IBS: A syndrome with multiple possible triggers (gut-brain interaction, stress, motility issues) and no single detectable bacterial cause.
2. Where They Occur in the GI Tract
SIBO: Small intestine — the main site of nutrient absorption.
IBS: Often associated with dysfunction in the large intestine.
3. Symptom Patterns
SIBO: Bloating and gas are often the most prominent symptoms, and nutrient malabsorption (like B12 or iron deficiency) can occur.
IBS: Pain and discomfort related to bowel movements are often more prominent, with symptom patterns that vary widely.
4. Diagnostic Methods
SIBO: Typically diagnosed with breath tests that measure gases produced by bacterial fermentation.
IBS: Diagnosed clinically based on symptoms, often using established criteria like Rome IV after other conditions are ruled out.
5. Impact on Digestion
SIBO: Can lead to fat malabsorption and floating or greasy stools due to bacterial interference with digestion.
IBS: Doesn’t usually cause malabsorption itself, though symptoms can overlap.
Why They’re Often Confused
SIBO and IBS share overlapping symptoms — like bloating, gas, diarrhea, constipation, and abdominal discomfort — which is why many people with SIBO are initially diagnosed with IBS.
How This Helps You
Understanding the differences can:
Improve diagnosis accuracy
Help tailor treatment and dietary approaches
Reduce trial-and-error frustration
If you suspect one condition but your symptoms aren’t improving with standard IBS management, it may be worth discussing SIBO testing with your healthcare provider.