What Is SIBO? Understanding the Root Cause of Many Digestive Symptoms

Bloating, gas, heartburn, and irregular bowel movements are some of the most common concerns I hear from patients in my practice.

Many people have been told they have IBS, sensitive digestion, or that they simply need to “manage stress.” But for many, there is an underlying cause that has never been properly identified.

What Is SIBO?

SIBO stands for Small Intestinal Bacterial Overgrowth. It's a condition where excessive amounts of bacteria grow in the small intestine—an area that should normally contain very few bacteria.

These bacteria feed on certain carbohydrates and fibers, including lactose and fructose, and other foods on the Non-FODMAPS Diet. When they munch on and ferment these foods, they produce hydrogen and methane gases.

When too many bacteria settle in the small intestine, it creates congestion and “traffic jams” that slow digestion and irritate the gut lining.

Common Symptoms of SIBO

• Abdominal bloating and distension

• Excessive gas or belching

• Abdominal pain or cramping

• Diarrhea, constipation, or alternating between both

• Nausea

• Heartburn or reflux

• Feeling full quickly after eating

The Strong Link Between SIBO and IBS

Research over the past 15 years has shown a strong connection between SIBO and IBS. Studies suggest that up to 84% of people diagnosed with IBS test positive for SIBO.

Even more importantly, when SIBO is properly treated, IBS symptoms often improve significantly or resolve. This is why SIBO is now considered one of the leading root causes of IBS.

Why Does SIBO Develop?

ROOT CAUSE #1 – Dysfunction of the Migrating Motor Complex (MMC)

The primary driver of SIBO is dysfunction of the Migrating Motor Complex (MMC). The MMC is a cleansing wave of muscle contractions that:

• Occurs every 3–4 hours between meals

• Moves waste through the intestines

• Sweeps excess bacteria into the colon

When this system is impaired, bacteria are not cleared effectively. Over time, they begin to accumulate in the small intestine.

ROOT CAUSE #2 – Post-Infectious Autoimmune Reactions

One of the most common causes of MMC dysfunction is an autoimmune reaction after food poisoning or traveler’s diarrhea. Research suggests that about 1 in 5 people develop this reaction following an intestinal infection. This helps explain why digestive symptoms often begin after a stomach illness and never fully resolve.

ROOT CAUSE #3 – Additional Risk Factors

Several other factors can increase the risk of developing SIBO, including:

• Low stomach acid

• Bile insufficiency

• Intestinal strictures

• Chronic use of medications such as PPIs

• Gluten/wheat intolerance

• Crohn’s disease

• Ulcerative colitis

• Prior abdominal surgery

  
  

These factors can slow digestion, weaken immune defences, or disrupt gut motility—creating an environment where bacteria can overgrow.

How Is SIBO Diagnosed?

SIBO is most commonly diagnosed using a SIBO Breath Test. This non-invasive test measures hydrogen and methane gases produced by bacteria after consuming a lactulose solution. Elevated gas levels indicate bacterial overgrowth in the small intestine. Accurate testing is essential for creating an effective and individualized treatment plan.

Treating the root cause allows true healing—rather than masking symptoms with medication.

Conditions Commonly Associated With SIBO

Because SIBO affects digestion, immunity, and nutrient absorption, it is linked to many other health concerns.

These may include:

• Acne and rosacea

• Nutrient deficiencies such as iron deficiency anemia

• Autoimmune conditions

• Chronic fatigue/ Fibromyalgia

• GERD and reflux

• Hypothyroidism

• Inflammatory bowel disease

• Neurological symptoms

• Post-surgical digestive issues

• Skin conditions

Basic Supportive Steps for Anyone With Digestive Symptoms

Here are some foundational steps that benefit most people with suspected SIBO:

• A Non-FODMAPS diet often helps reduce symptoms quickly but should not used as a long term solution, as it can lead to nutrient deficiencies

• Avoid unnecessary long-term acid-suppressing medications

• Practice stress management and prioritize sleep

• Avoid grazing and allow time between meals

If you are struggling with ongoing digestive symptoms, I am happy to guide you further.Let’s chat in a 15-minute complimentary Discovery Call to see if SIBO testing and personalized support are right for you.

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Disclaimer: All content in this blog is created and published online for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice.