What Causes SIBO?

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There are many possible causes of SIBO, including various diseases (such as food poisoning), many types of injury or trauma (such as surgery), genetic factors, and certain medications (such as opioid pain killers). The causes of SIBO create deficiencies or failures of the body’s physiologic and anatomic protections against SIBO, which then allow bacteria to overgrow in the small (or large) intestine. The two main physiologic and anatomic protections against SIBO are normal small intestine motility (migrating motor complex), and having normal abdominal anatomy. Ultimately, anything that allows bacteria to back up in the small intestine (i.e. anything that can cause deficient migrating motor complex or change small intestine anatomy) can cause SIBO. 

Frequently Cause SIBO (alphabetical order)

• Abnormal Anatomy
  Adhesions, Diverticulosis, Endometriosis, Fistula, Ileocecal Valve absence or dysfunction, Stricture, Superior Mesenteric Artery Syndrome, Surgical Blind Loop, Tumor (abdominal), Volvulus ...
  
• Adhesions (abdominal)
• Appendicitis
• Diabetes
• Ehlers-Danlos Syndrome
• Endometriosis
• Food Poisoning
• Hypothyroid/Hashimoto's Thyroiditis
• Inflammatory Bowel Disease: Crohn's Disease, Ulcerative Colitis
• Medications: Opioid Painkillers
• Mold Illness

Notable Risk Factors of SIBO (alphabetical order)

• Celiac Disease
• Hypochlorhydria
• Immune Deficiency
• Lyme Disease
• Medications: Antibiotics, Proton Pump Inhibitors, GLP-1 agonists
• Parasitic Infection
• Parkinson’s Disease
• Postural Orthostatic Tachycardia Syndrome (POTS)
• Scleroderma (Systemic Sclerosis)
• ​Surgery (abdominal)
• Traumatic Brain Injury

See "Risk Factors" below for more.

Underlying Causes of SIBO Masterclass with Dr. Allison Siebecker

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Food Poisoning: the Most Common Cause of SIBO
Food poisoning (also called traveler’s diarrhea or stomach flu) is the most common cause of SIBO. SIBO from food poisoning is also called post-infectious IBS, and is thought to account for 2/3 of all IBS cases. Food poisoning triggers an autoimmune process that damages small intestine nerves (Interstitial cells of Cajal) and decreases the migrating motor complex (MMC), the vital motility of the small intestine that protects against SIBO. Once the MMC decreases, bacteria accumulate, causing overgrowth. This means SIBO from food poisoning is autoimmune mediated.

Most people know food poisoning as a short-term, often severe illness of vomiting and diarrhea. However, many cases of food poisoning are mild, and are therefore overlooked, meaning food poisoning can be a cause of SIBO without someone remembering having had it. This is further complicated by the fact that the onset of SIBO after food poisoning is often delayed by 3-6 months, making the connection even less less obvious. Fortunately, there are blood tests that can diagnose SIBO from food poisoning. While there is currently no known cure for this underlying cause of SIBO, treatment options are being investigated by Dr. Pimentel and team,

How Food Poisoning Causes SIBO

During food poisoning, pathogenic bacteria secrete cytolethal distending toxin B (CDT B) into the small intestine, which looks similar to the protein vinculin. Vinculin is a component of small intestine nerve cells called the interstitial cells of Cajal (ICC). The ICC nerve cells generate the migrating motor complex (MMC). Because CDT B toxin and vinculin look similar, the immune system mistakenly targets the body's vinculin along with the foreign CDT B toxin. Thus, the immune system damages the ICC nerve cells through friendly fire (also called molecular mimicry), which decreases the number of MMC waves, creating stasis in the small intestine. Stasis allows bacteria to accumulate, creating SIBO. [Adapted with permission Siebecker 2018, from Pimentel 2013.]

Watch the MMC in motion here (+ more MMC videos here)

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Adhesions: a Common Cause of SIBO
Adhesions are a type of scar tissue formed in the abdomen as a result of inflammation, infection, or injury, such as surgery, or a car or sports accident. Adhesions have strong glue-like bonds that can alter normal anatomy and create a partial small intestine obstruction, which can slow the normal flow of bacteria through the intestine, allowing microbes to accumulate and SIBO to develop. Many diseases cause adhesions, including appendicitis, endometriosis, Ehlers-Danlos syndrome, and inflammatory bowel disease.

Many people are unaware they have adhesions, or have never heard of them, making them an under-recognized and overlooked cause of SIBO. Adhesions are best detected by a barium swallow test. Barium solution is swallowed and X-ray pictures are taken over time and in different positions, to show the flow of barium through the intestines from different angles.
— When ordering this test, use the following instructions to assure a thorough exam:

• “Rule out adhesions with multiple spot films and positional changes to visualize each segment of bowel” (with this instruction, radiologists will take 20-35 pictures vs. 4-5 and understand what to look for)
  

Treatment for adhesions include adhesiolysis surgery (which could create more adhesions), and non-surgical options: Clear Passage® Approach (evidence-based, proven manual therapy); Frequency Specific Microcurrent, and Neural Therapy.

Abdominal adhesions (wikimedia commons)

Risk Factors for SIBO

The level of risk is not the same for all factors listed. Some are frequent causes of SIBO, while others simply increase risk.

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For more details about underlying causes of SIBO, see Courses, and sign up to receive notification of Dr. Siebecker's free classes.

More Resources: SIBO Causes playlist on my YouTube  

   Learn more

WHAT IS SIBO SYMPTOMS ASSOCIATED DISEASES SIBO & IBS TESTING TREATMENT SIBO DIET COURSES

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