SIBO: 12 Causes, Symptoms, Treatment, Diet, and Prevention that can be life-changing

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Small intestinal bacterial overgrowth (SIBO) is more prevalent than experts previously believed. Some estimate that SIBO could affect up to 15% of healthy people without them even knowing it.

Living with SIBO decreases your quality of life. SIBO may be caused by irritable bowel syndrome (IBS), hypothyroidism, or a whole host of other medical conditions. 

SIBO can also be an underlying condition that triggers other diseases.

What is SIBO?

SIBO is a digestive system disorder that stands for “small intestine bacterial overgrowth”. SIBO occurs when excess bacteria is growing in your small intestine when most of your gut bacteria should be growing in your large intestine.

This can lead to malnutrition or other gastrointestinal tract disorders, such as IBS.

A majority of IBS patients also have SIBO. Here at PrimeHealth, when we treat someone for IBS, we test for SIBO. The test often comes back positive. 

Treating SIBO often reverses IBS permanently, especially when combined with other IBS-healing strategies.

A bacterial overgrowth can break down undigested food in your small intestine, which produces hydrogen. However, hydrogen may feed other small organisms in your small intestine and produce methane. 

SIBO may result in excess hydrogen, methane, or both, trapped in your digestive tract.

What causes SIBO?

How do you get SIBO? There are several ways to get SIBO.

The root cause of SIBO is a complex and controversial topic. Because there are multiple separate underlying causes of SIBO, conventional doctors may say the cause of SIBO is unknown.

However, we now know several diseases that are scientifically linked to SIBO. 

Medical conditions that may trigger or be associated with SIBO include:

  1. Hypothyroidism
  2. Cirrhosis of the liver
  3. Diabetes
  4. Scleroderma
  5. Celiac disease
  6. Fibromyalgia
  8. Parkinson’s disease
  9. Small bowel diverticulosis
  10. Crohn’s disease
  11. Ulcerative colitis
  12. Irritable bowel syndrome

Risk Factors

5 risk factors that increase your risk of SIBO include:

  1. Old age
  2. Female gender
  3. Alcohol use
  4. Previous bowel surgery
  5. Certain medications, such as antibiotics or proton pump inhibitors

SIBO Symptoms

SIBO may cause or be caused by IBS. This is why SIBO and IBS share so many symptoms.

What are the symptoms of SIBO? Common symptoms of SIBO include:

  • Abdominal pain
  • Bloating
  • Cramping
  • Stomach growling
  • Flatulence
  • Diarrhea
  • Constipation
  • Nausea
  • Nutritional deficiency
  • Fat malabsorption
  • Weight loss
  • Fatigue
  • Rash
  • Joint pain
  • Asthma
  • Skin conditions, such as acne, eczema, rosacea

Call your doctor right away if you experience SIBO symptoms such as trouble breathing, unusual food cravings, or pale skin. This may indicate your SIBO has caused malnutrition, which may be life threatening.

How to Diagnose SIBO

A primary care doctor or a specialist, such as a gastroenterologist, may diagnose SIBO using several methods, including a breath test.

Here at PrimeHealth, we always run SIBO breath tests when diagnosing IBS. Up to 84% of IBS patients test positive for SIBO.

Glucose, xylose, and lactulose breath tests are less invasive diagnostics than blood tests and produce reliable test results for SIBO.

  1. A methane-positive breath test usually indicates constipation-dominant IBS. (IBS-C)
  2. A hydrogen-positive breath test usually indicates diarrhea-dominant IBS. (IBS-D)

Other ways to diagnose SIBO include:

  • Symptoms checklist
  • Physical examination
  • Personal medical history
  • Family medical history
  • Blood testing
  • Urine testing
  • Comprehensive stool testing

SIBO Treatment Options

How do you treat SIBO? There are several ways to treat SIBO, but it boils down to 3 steps:

  1. Reduce small intestine bacterial overgrowth
  2. Restore gut motility
  3. Repopulate good bacteria

Although your small intestine is naturally home to some bacteria, most bacteria should be living in your large intestine.

Can SIBO go away on its own? No, SIBO needs to be addressed to go away. You may unintentionally treat SIBO if you change your diet, switch out medications, or start to exercise regularly.


Here at PrimeHealth, we prefer to keep pharmaceuticals to a minimum. They can be overused and often come with adverse side effects, so they should be used strategically. 

Medications we may prescribe:

  • Prucalopride (Motegrity) and low-dose naltrexone are promotility agents used to treat IBS-C and SIBO. It is important to restore gut motility to reduce small intestine overgrowth and get beneficial bacteria down to your large intestine. Both of these medications are prescribed for “off-label” treatment of SIBO or IBS.
  • Rifaximin is the generic of Xifaxan, an FDA-approved antibiotic to treat IBS-D. Rifaximin seems to effectively treat SIBO. (While several insurance companies don’t want to pay its high price tag, PrimeHealth uses pharmacies in Canada to obtain the generic form at a reasonable price.)
  • Prokinetics help strengthen the lower esophageal sphincter and help control acid reflux. A 2018 study showed that prokinetics enhanced gut motility and reduced the risk of SIBO in patients taking proton pump inhibitors.
  • Neomycin is an antibiotic we may use for methane-dominant SIBO. 
  • Antispasmodics relieve cramping. These may also cause constipation, so antispasmodics are usually only for hydrogen-dominant SIBO patients.

We may also suggest biofilm disruptors, such as  systemic enzymes (ie: Interfase Plus). Bacteria may form a protective biofilm that is resistant to antibiotics. A biofilm disruptor helps to neutralize the bacteria’s defenses and leave the bacteria vulnerable

A 2014 study concluded that certain herbal blends were as effective as Rifaximin in treating SIBO. For some SIBO sufferers, the all-natural route is the preferred route.

Dietary Supplements & Herbs

Oil of oregano and allicin may treat SIBO. Certain herbal blends, like Dysbiocide or FC-cidal, may also treat SIBO.

Usually, probiotics are not ideal for correcting this overgrowth. Probiotics are supposed to repopulate your gut with beneficial bacteria. If you have an overgrowth in your small intestine, probiotics may populate in your small intestine instead of the intended large intestine, multiplying the problem.

On the other hand, human studies show that probiotics may counteract SIBO symptoms better than antibiotics.

You need to repopulate your beneficial bacteria after the overgrowth is taken care of. Until we fully understand which probiotics help SIBO and which do not, you probably shouldn’t use probiotics until after your SIBO is reversed.

SIBO Diets

We suggest the same diet for SIBO as we do for IBS: the low-FODMAP diet.

The most common SIBO diet is the low-FODMAP diet, or some less restrictive version of it (like Whole30). The low-FODMAP diet starves the harmful bacteria in your gut of fermentable carbs it needs, including if the overgrowth is in your small intestine (SIBO).

FODMAP stands for “fermentable oligosaccharides, disaccharides, monosaccharides and polyols”. Simply put, a FODMAP is a carbohydrate that can be fermented. Avoiding FODMAPs makes it harder for harmful bacteria to thrive in your small intestine.

A SIBO diet still includes:

  • Lean proteins
  • Healthy fats
  • Non-starchy vegetables
  • Leafy greens
  • Fruit, in moderation

However, this diet may not be right for all SIBO patients. The low-FODMAP diet is not recommended while treating SIBO with antibiotics. These antibiotics are more effective when you eat foods containing FODMAPs.

It may also be wise to cut out food allergens (wheat, dairy, etc.) that may be causing gut health problems.

How to Prevent SIBO

SIBO may recur if you do not make permanent changes to your diet or lifestyle.

4 tips for preventing SIBO:

  1. Avoid added sugar and refined carbs
  2. Lay off the probiotics if they worsen symptoms
  3. Reduce daily stress
  4. Exercise regularly

The key to preventing a SIBO relapse is ensuring that gut motility is restored, since gut motility is usually the reason an overgrowth formed in your small intestine.

If a certain medical condition is the underlying cause of your SIBO, treating your root condition may help resolve SIBO for good.


If SIBO goes untreated, it can lead to complications. These complications may greatly reduce your quality of life and, in rare cases, become life-threatening.

Complications of untreated SIBO:

  • Irritable bowel syndrome
  • Malnutrition
  • Dehydration
  • Neuropathy
  • Leaky gut syndrome
  • Vitamin deficiency:
    • Night blindness (vitamin A deficiency)
    • Soft bones or tetany (vitamin D deficiency)
    • Slower blood clotting (vitamin K deficiency)
    • Anemia or fatigue (vitamin B12 deficiency)

Because SIBO can affect your gut microbiome (the balance of beneficial bacteria in your gut), SIBO may indirectly affect your immune system. 

Much of your immune system exists in your gut, and relies on beneficial bacteria to protect it. SIBO may lead to an increase of harmful bacteria, followed by immune dysfunction.

Long-Term Prognosis

SIBO (small intestinal bacterial overgrowth) is a relatively common problem in adults. It can be triggered by hypothyroidism, antibiotic overuse, diabetes, and more. 

SIBO may cause IBS, malnutrition, or vitamin deficiencies.

Effective SIBO treatments — including prescription drugs and all-natural options — may offer you a chance to reclaim your quality of life.

Join PrimeHealth’s Gut Health Group Program to work directly with our providers to give your gut a makeover! This program begins Sept 20, 2022 and only a few virtual spots remain. Sign up today!


  1. Revaiah, P. C., Kochhar, R., Rana, S. V., Berry, N., Ashat, M., Dhaka, N., … & Sinha, S. K. (2018). Risk of small intestinal bacterial overgrowth in patients receiving proton pump inhibitors versus proton pump inhibitors plus prokinetics. JGH open, 2(2), 47-53. Full text:
  2. Chedid, V., Dhalla, S., Clarke, J. O., Roland, B. C., Dunbar, K. B., Koh, J., … & Mullin, G. E. (2014). Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Global Advances in Health and Medicine, 3(3), 16-24. Full text:
  3. Soifer, L. O., Peralta, D., Dima, G., & Besasso, H. (2010). Comparative clinical efficacy of a probiotic vs. an antibiotic in the treatment of patients with intestinal bacterial overgrowth and chronic abdominal functional distension: a pilot study. Acta gastroenterologica Latinoamericana, 40(4), 323-327. Abstract:
  4. Pimentel, M., Morales, W., Rezaie, A., Marsh, E., Lembo, A., Mirocha, J., … & Barlow, G. M. (2015). Development and validation of a biomarker for diarrhea-predominant irritable bowel syndrome in human subjects. PLoS One, 10(5), e0126438.
  5. Dukowicz, A. C., Lacy, B. E., & Levine, G. M. (2007). Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterology & hepatology, 3(2), 112. Full text:
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