If you’ve ever felt persistently bloated, reacted to foods that used to feel safe, or struggled with digestive symptoms, you’re not alone. One of the most overlooked causes of chronic digestive dysfunction is Small Intestinal Bacterial Overgrowth (SIBO).
What Is SIBO?
SIBO occurs when bacteria that belong in the large intestine move into the small intestine and begin to overgrow. The small intestine’s primary role is digestion and nutrient absorption, not fermentation. When excess bacteria are present, they ferment carbohydrates too early in the digestive process, creating gas, inflammation, and functional disruption that contribute to common symptoms like bloating, discomfort, and food sensitivities.
There are two main types of SIBO:
Hydrogen-Dominant SIBO – often associated with diarrhea and gas production
Methane-Dominant Overgrowth (IMO) SIBO – often associated with constipation and slower intestinal motility
Common SIBO Symptoms
Digestive symptoms
Bloating (especially after meals)
Excess gas or belching
Abdominal discomfort
Constipation, diarrhea, or mixed bowel patterns
Food sensitivities
Early fullness
Whole-body symptoms
Brain fog
Fatigue
Nutrient deficiencies (iron, B12)
Skin issues
Joint discomfort
Hormonal dysregulation
Many patients notice symptoms worsen with healthy foods like vegetables, legumes, or fiber — which can feel confusing.
What Causes SIBO?
The gut relies on a cleansing wave called the Migrating Motor Complex (MMC) – a rhythmic process that sweeps bacteria downward between meals. When this system slows, bacteria accumulates. Factors that contribute to SIBO include long-term proton-pump inhibitor (PPI) therapy, hypothyroidism, food poisoning, antibiotic use, connective tissue disorders, anatomical abnormalities (e.g., diverticulosis, strictures), and chronic opioid use.
How SIBO Is Diagnosed
SIBO is diagnosed via a breath test, measuring hydrogen and methane gases after consuming a carbohydrate substrate, such as lactulose.
Treating SIBO
Effective SIBO treatment requires a comprehensive, phased approach. Initial therapy aims to reduce bacterial overgrowth through targeted antibiotics, herbal antimicrobials, or an elemental diet. Treatment then shifts toward restoring gastrointestinal function by supporting mucosal integrity, replenishing nutrients, and improving intestinal motility – a critical step in preventing recurrence. A short-term low-FODMAP dietary strategy is often used during treatment to minimize symptoms and decrease fermentation within the small intestine.
If persistent bloating, food sensitivities, or unexplained digestive symptoms sound familiar, SIBO may be worth investigating. Our providers can help determine whether testing is appropriate and develop a personalized treatment plan to address the root cause of your symptoms.
