Small intestinal bacterial overgrowth (SIBO) occurs when an excessive amount of bacteria develops within the small intestine. This condition often leads to uncomfortable symptoms such as chronic diarrhea, abdominal pain, and significant bloating.
Various factors can cause this syndrome, including impaired intestinal movement and specific anatomical changes. It may also lead to the malabsorption of essential nutrients, which can eventually result in malnutrition.
Management of SIBO is typically handled by a gastroenterologist who specializes in digestive health. Treatment plans often involve personalized dietary modifications, lifestyle changes, and the use of targeted antibiotics.
Main symptoms
The most common symptoms associated with small intestinal bacterial overgrowth (SIBO) include:
-
Chronic watery diarrhea
-
Abdominal pain or discomfort, particularly after eating
-
Excessive intestinal gas
-
A persistent feeling of bloating or indigestion
-
Bouts of diarrhea alternating with constipation
-
Loss of appetite
-
Malnutrition in severe or long-term cases
SIBO can interfere with the absorption of nutrients like fats, carbohydrates, and vitamins A, B12, D, or K. This malabsorption may lead to fatty stools, unintended weight loss, extreme fatigue, numbness in the extremities, muscle cramps, or anemia.
Because of these risks, it is important to see a gastroenterologist if you experience these symptoms. Early diagnosis is key to starting the most effective treatment plan for your specific needs.
How to confirm a diagnosis
Gastroenterologists typically diagnose SIBO by reviewing your medical history, evaluating your symptoms, and performing a breath test. The hydrogen breath test is the most common diagnostic tool used for this condition.
This test works because excessive bacteria in the small intestine release specific gases in higher-than-normal amounts. As a result, the breath test serves as an effective, non-invasive way to identify potential cases of SIBO according to the American College of Gastroenterology.
To perform the test, you must fast for eight hours before exhaling into a collection tube at a clinic. Afterward, you drink a specialized sugar solution, and additional breath samples are collected every two to three hours.
If SIBO is present, the levels of hydrogen or methane in the exhaled air typically rise significantly over time. When these levels exceed the normal threshold, the test result is considered positive.
If breath test results are inconclusive, a doctor may perform more invasive testing. This may involve taking a fluid culture from the small intestine to measure bacterial concentrations in a lab.
Possible causes
Small intestinal bacterial overgrowth can be triggered by several underlying factors, including:
-
Gastrointestinal motility disorders, such as irritable bowel syndrome (IBS), diabetes, or scleroderma
-
Low or absent stomach acid, known as hypochloridria or achlorhydria
-
Chronic pancreatic insufficiency
-
Structural changes in the small intestine, such as diverticulosis, strictures, or surgical adhesions
-
Immune system deficiencies, including IgA deficiency or AIDS
-
Changes in digestive enzymes or natural gut flora balance
The condition is also linked to the use of certain medications. Common examples include proton pump inhibitors (PPIs), antimotility drugs, and the frequent use of some antibiotics.
Treatment options
The goal of SIBO treatment is to eradicate the bacterial overgrowth and address any resulting nutritional gaps. This process should always be supervised by a medical professional to ensure safety and effectiveness.
The primary treatment methods for SIBO include:
1. Use of antibiotics
Based on clinical guidelines from the American College of Gastroenterology, the first priority is controlling the bacterial population in the small intestine using prescription antibiotics. Gastroenterologists commonly prescribe medications like rifaximin, ciprofloxacin, or metronidazole for this purpose.
While most patients take these antibiotics in tablet form at home, severe cases involving dehydration or malnutrition may require hospitalization. In these instances, patients may receive intravenous fluids or parenteral nutrition.
2. Diet changes
While there is no specific diet that cures SIBO on its own, certain nutritional adjustments can significantly reduce symptoms:
-
Eating smaller, more frequent meals rather than three large ones
-
Reducing the intake of high-sugar foods and beverages
-
Identifying and avoiding trigger foods, such as those containing gluten or lactose
Additionally, many patients find relief by following a Low FODMAP diet, which limits fermentable carbohydrates that feed gut bacteria.
Doctors may also recommend supplements to correct nutritional deficiencies. Depending on your bloodwork, this might include iron, vitamin B1, B3, B12, or vitamin D.
3. Taking probiotics
Probiotics may help the gut restore its natural bacterial balance and reduce the overgrowth, though more research is needed to confirm their total effectiveness.
You can also incorporate probiotics naturally through fermented foods. Good options include plain yogurt, kefir, and kimchi.