Root Causes of SIBO

Explore the 7 Root Causes of SIBO

When it comes to understanding Small Intestinal Bacterial Overgrowth (SIBO), delving into the root causes of SIBO is essential for effective management and treatment. SIBO is a complex digestive disorder characterised by an abnormal increase in bacterial numbers in the small intestine. The symptoms, ranging from bloating to abdominal pain, are apparent, but comprehending the underlying issues is crucial.


Small Intestinal Bacterial Overgrowth (SIBO) may sound like a complex medical term, but its impact on daily life can be profound. If you’ve found yourself grappling with unexplained digestive issues, it’s time to dig deeper and unearth the root causes of SIBO.

At its core, SIBO occurs when there’s an abnormal increase in the number of bacteria in the small intestine. This seemingly simple imbalance can give rise to a myriad of uncomfortable symptoms, from bloating and gas to more severe complications if left untreated. So, what lies at the heart of this gastrointestinal enigma?

One major culprit is the delicate balance of bacteria in our gut. Normally, the small intestine maintains a relatively low bacterial population, but various factors can upset this equilibrium. Antibiotic use, for instance, not only targets harmful bacteria but can also disrupt the beneficial ones, paving the way for SIBO to take root.

Digestive anatomy also plays a pivotal role. Structural abnormalities, such as intestinal strictures or adhesions, can create stagnant areas where bacteria thrive. Motility issues, where the muscles of the digestive tract fail to move food efficiently, contribute to the stagnation, offering bacteria a breeding ground.

Let’s not forget the impact of diet. Highly processed foods and diets rich in sugars can fuel bacterial overgrowth, transforming our gut into a paradise for unwanted microorganisms. Gluten sensitivity has also been linked to SIBO, emphasizing the intricate connection between what we eat and the health of our gut.

Stress, the modern-day nemesis, is another underestimated factor. Chronic stress weakens the immune system and alters gut motility, setting the stage for bacterial overgrowth. In the relentless hustle of daily life, it’s easy to overlook the profound influence stress can have on our digestive well-being.

In the journey to understand and conquer SIBO, it’s crucial to address these root causes. By unravelling the mysteries behind this condition, we empower ourselves to make informed choices that promote a balanced and thriving gut. Remember, the key to lasting relief lies not just in treating symptoms but in addressing the underlying factors that fuel the fire of SIBO.

Root Causes of SIBO
Explore the 7 Root Causes of SIBO


Root Cause of SIBO #1: Pancreatic Insufficiency

Pancreatic insufficiency occurs when the pancreas does not produce enough digestive enzymes, including lipases, amylases, and proteases, which are crucial for breaking down fats, carbohydrates, and proteins in the small intestine.

When there is inadequate production of these enzymes, the digestion and absorption of nutrients in the small intestine are compromised. This can lead to undigested food reaching the lower parts of the digestive tract, providing a substrate for bacterial overgrowth. Bacteria may then ferment the undigested carbohydrates, producing gases and leading to an altered microbial environment in the small intestine, contributing to SIBO 1.

It’s essential to note that the relationship between pancreatic insufficiency and SIBO can be complex, and other factors may also play a role in the development of SIBO. If you suspect pancreatic insufficiency or SIBO, it is advisable to consult with a healthcare professional for proper diagnosis and management. They may perform tests such as the faecal elastase test or pancreatic function test (secretin-cerulein test). Remember to speak to your healthcare provider about how much fat to consume before the faecal elastase test to receive the best result.

Root Cause of SIBO #2: Impaired Motility

The migrating motor complex (MMC), a pattern of coordinated contractions sweeping through the small intestine during fasting, plays a vital role in preventing bacterial accumulation. However, impaired gastrointestinal motility, commonly seen in conditions like irritable bowel syndrome (IBS) or diabetic neuropathy, stands out as a primary root cause of SIBO. When the MMC falters, the risk of bacterial overgrowth significantly rises 2.

Root Cause of SIBO #3: Structural Abnormalities

Structural abnormalities within the digestive system create pockets where bacteria can thrive. Conditions like intestinal adhesions, strictures, or diverticula disrupt the normal flow of digestive contents, fostering an environment favourable to SIBO development. Surgical interventions or abdominal trauma may introduce these structural abnormalities, further increasing the likelihood of bacterial overgrowth 3.

Root Cause of SIBO #4: Hypochlorhydria

Adequate stomach acid is crucial for maintaining a sterile upper gastrointestinal tract. Hypochlorhydria, or low stomach acid, sets the stage for SIBO. When stomach acid is insufficient, bacteria from the stomach can migrate into the small intestine, finding a hospitable environment to proliferate and disrupt normal digestive processes 4.

Root Cause of SIBO #5: Dysfunction of the Ileocecal Valve

The ileocecal valve serves as a crucial barrier preventing the backward flow of colonic contents into the small intestine. Dysfunction of this valve can contribute to SIBO by allowing the reflux of bacteria from the colon. Factors such as infections, inflammation, or anatomical abnormalities can compromise the integrity of the ileocecal valve, facilitating bacterial overgrowth 5.

Root Cause of SIBO #6: Bile Dysfunction

Bile dysfunction can contribute to Small Intestinal Bacterial Overgrowth (SIBO), though it’s just one of several potential factors. Bile is a digestive fluid produced by the liver and stored in the gallbladder. It plays a crucial role in digestion, particularly in the emulsification and absorption of fats. When bile flow is impaired, it can impact the digestion and absorption of nutrients, potentially creating an environment conducive to SIBO 6. Here’s how bile dysfunction can be related to SIBO:

  1. Bile as an Antimicrobial Agent:
    • Bile has antimicrobial properties that help control the growth of bacteria in the small intestine. Impaired bile flow may reduce this protective effect, allowing bacteria to proliferate.
  2. Bile Acids and Motility:
    • Bile acids can influence gut motility. Insufficient bile may affect the normal movement of the digestive tract, potentially leading to stagnation of food and bacterial overgrowth in the small intestine.
  3. Bile and Digestion of Fats:
    • Bile is essential for the digestion and absorption of fats. If there is a lack of bile or impaired bile function, it can result in malabsorption of fats. Undigested fats can serve as a substrate for bacterial overgrowth in the small intestine.
  4. Underlying Conditions:
    • Certain conditions, such as gallbladder dysfunction, gallstones, or liver diseases, can disrupt bile flow. These conditions may be associated with an increased risk of SIBO.

Root Cause of SIBO #7: Dietary Factors

Dietary choices are pivotal in the development of SIBO. Diets rich in refined carbohydrates and sugars provide fuel for bacterial proliferation. Additionally, low-fibre diets compromise the integrity of the intestinal lining, creating an environment where bacteria can adhere and multiply.

What Next?

If you suspect you might have SIBO, getting a diagnosis through a SIBO breath test is important. Depending on the test results, you might need a personalised treatment plan. Since the causes of SIBO can vary from person to person, it’s crucial to take a tailored approach to treatment. The treatment plan at the SIBO clinic is specific to addressing your root cause and may involve a mix of adjusting your diet, and lifestyle, natural antimicrobials and, in some cases using prokinetics to help improve gut motility.


  1. Gabrielli M, D’Angelo G, Di Rienzo T, et al. Association of small intestinal bacterial overgrowth with concomitant pancreatic exocrine insufficiency in celiac patients: A prospective, case-control study. Am J Gastroenterol.2007;102(4):848-852.
  2. Bures, J., Cyrany, J., Kohoutova, D., et al. (2010). Small intestinal bacterial overgrowth syndrome. World J Gastroenterol, 16(24), 2978–2990. 
  3. Saltzman, J.R., Russell, R.M. (1995). Nutritional consequences of intestinal bacterial overgrowth. Compr Ther, 21(8), 523–527. 
  4. Pimentel, M. (2010). Review of rifaximin as treatment for SIBO and IBS. Expert Opin Investig Drugs, 19(4), 531–538. 
  5. DiBaise, J.K., Ptel, N., Noelting, J., et al. (2011). The role of pancreatic enzyme supplementation in patients with diarrhea and malabsorption. J Clin Gastroenterol, 45(3), 234–238. 
  6. Grace, E. (2014). Uninvited Guests: The Impact of Small Intestinal Bacterial Overgrowth. Gastroenterol Nurs, 37(5), 343–352. 
  7. Chedid, V., Dhalla, S., Clarke, J.O., et al. (2016). Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med, 5(4), 24–29. 



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