5 Health Conditions That Are Associated with Small Intestinal Bacterial Overgrowth (SIBO)

15% of the United States population is reported to experience irritable bowel syndrome (IBS). Studies suggest that up to 80% of people with IBS may have small intestinal bacterial overgrowth (SIBO). This could mean that a significant number of people might have SIBO, even if they haven't been diagnosed with IBS.

SIBO is associated with various conditions and may both contribute to and result from other health issues. This article will explore SIBO and some related conditions that might benefit from SIBO testing as part of a functional medicine approach.

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What is Small Intestinal Bacterial Overgrowth (SIBO)?

SIBO refers to an increase in bacteria in the small intestine, where typically, bacteria are more prevalent in the colon. In a healthy system, bacteria pass through the small intestine without overpopulating. When this balance is disrupted, it can lead to inflammation and digestive issues. (1)

There are three types of SIBO, identified by breath tests and the types of gases produced. Hydrogen-SIBO involves hydrogen-producing bacteria, hydrogen sulfide-SIBO involves hydrogen sulfide-producing bacteria, and intestinal methanogen overgrowth (IMO) involves archaea in the intestines. (1)

SIBO Symptoms

Common symptoms of SIBO are similar to those of IBS and may include: (2, 3)

Abdominal pain
Abdominal distension and bloating
Indigestion
Flatulence
Burping
Nausea
Diarrhea: may be linked to hydrogen and hydrogen sulfide excess
Constipation: may be linked to methane excess

Malabsorption associated with SIBO might lead to unintentional weight loss, fatigue, and fatty stools. Nutrient levels, such as iron and vitamins B1, B3, B12, and D, may be affected. (2)

Leaky gut and related immune responses might contribute to symptoms beyond digestion, such as: (1)

Headaches
Joint pain
Brain fog
Skin symptoms: eczema, rosacea, psoriasis, and other rashes
Changes in mood: depression and anxiety

What Causes SIBO?

The body has natural defenses against bacterial overgrowth in the small intestine, including digestive enzymes, peristalsis, the ileocecal valve, and secretory IgA (sIgA). These mechanisms help manage bacteria levels. (2)

SIBO can develop due to various factors, including changes in motility, immune function, digestive enzymes, and anatomy.

Risk Factors for Developing SIBO

Age, medical conditions, surgeries, and medications can affect the body's defenses against SIBO, potentially increasing risk.

Older age may be linked to lower stomach acid and motility. (3)

Abdominal surgery and radiation therapy might impact the mucosal lining and contribute to changes in intestinal movement. (3)

Certain medical conditions can affect immune response, motility, and intestinal structure, such as:

Diabetes mellitus
Hypothyroidism
Autoimmune diseases: lupus, celiac disease, inflammatory bowel disease (IBD), scleroderma
Digestive enzyme deficiencies due to low stomach acid (hypochlorhydria), pancreatitis, gallbladder disease, liver disease, and exocrine pancreatic insufficiency (EPI)
Colon cancer

Certain medications might also influence SIBO risk. Antibiotics can affect intestinal motility and microbiome balance. (3) Opiates and muscle relaxants may impact motility. Proton pump inhibitors (PPIs) and other acid-reducing medications can lead to low stomach acid.

5 Medical Conditions Associated with SIBO

SIBO may play a role in the development and progression of various conditions. Here are some conditions where SIBO might be considered:

Rosacea

Research suggests a possible link between SIBO and rosacea, a skin condition. Changes in immune responses and inflammation related to SIBO might contribute to rosacea. Some studies indicate that addressing SIBO may help manage rosacea symptoms. (6)

Restless Legs Syndrome (RLS)

RLS is a condition characterized by uncomfortable sensations in the legs. Some studies suggest a connection between IBS, SIBO, and RLS, with potential improvements in RLS symptoms when SIBO is addressed. Possible explanations include immune changes and nutrient deficiencies linked to SIBO.

Interstitial Cystitis (IC)

IC, or Bladder Pain Syndrome, is a chronic condition affecting the bladder. Some research indicates a potential link between IBS, SIBO, and IC, with some patients experiencing symptom improvement when SIBO is addressed. Hydrogen sulfide, associated with SIBO, may play a role in bladder discomfort.

Diabetes

People with diabetes may have a higher likelihood of experiencing SIBO. Complications like nerve damage and slowed stomach emptying in diabetes might increase SIBO risk. Conversely, SIBO might affect glucose control and digestive health in diabetes. (8, 9)

Autoimmune Arthritis

Intestinal imbalances might contribute to inflammation and joint discomfort in autoimmune arthritis. Some studies suggest a link between SIBO and conditions like rheumatoid arthritis and lupus, with SIBO potentially influencing disease activity.

Functional Medicine Labs to Evaluate SIBO

Hydrogen breath tests are commonly used to assess SIBO, offering a noninvasive alternative to more invasive methods. (4)

These tests can be done at home, following specific dietary and fasting guidelines. Patients provide breath samples after consuming a glucose or lactulose solution, with samples collected at intervals over a few hours.

Traditional breath tests measure hydrogen and methane gases. A positive result may be indicated by specific changes in gas levels. (5)

Hydrogen levels increase by 20ppm within three hours from baseline
Methane levels of at least 10ppm at any timepoint during the test
If the test does not meet positive criteria for hydrogen or methane levels, a combined hydrogen and methane level increase by at least 15ppm within three hours from baseline may indicate a positive test.

The trio-smart test measures hydrogen, methane, and hydrogen sulfide gases. Similar criteria are used for hydrogen and methane, with a hydrogen sulfide level of at least 3ppm indicating a positive result.

Other Labs for Evaluating SIBO and Related Conditions

Functional medicine labs can help tailor treatment options. Here are some common tests for SIBO and related conditions:

Comprehensive Stool Analysis

A comprehensive stool analysis can identify patterns related to SIBO and assess factors like malabsorption and inflammation.

The GI-MAP test is often used to check for H. pylori, which may be linked to rosacea.

Nutritional Evaluation

Nutrient imbalances related to SIBO can be assessed with a comprehensive nutritional assessment. Common findings include changes in folate, iron, vitamin D, and B12 levels.

Blood Sugar

A comprehensive blood workup for diabetes and insulin resistance includes tests like CBC, CMP, hemoglobin A1c (HbA1c), insulin, and a lipid panel.

Thyroid

Thyroid function can affect gut motility. A comprehensive thyroid panel can help assess thyroid health.

Autoimmunity

The Cyrex Array 5 panel can help evaluate autoimmune activity. Testing for antibodies related to conditions like SLE and type 1 diabetes can provide insights into autoimmune processes.

Slowed gastrointestinal activity may also be linked to autoimmunity triggered by infections. Testing for antibodies related to post-infectious IBS and SIBO can help confirm these connections.

Imaging

Imaging tests like antroduodenal manometry, endoscopy, and barium follow-through can help identify structural issues related to SIBO and IMO.

A Functional Medicine Approach to Supporting SIBO and Related Conditions

Addressing SIBO with antibacterial therapy may help improve gastrointestinal symptoms and support overall health in conditions like RLS, IC, autoimmune disease, rosacea, and diabetes.

SIBO Management

Both antibiotic and herbal antimicrobials have been studied for their potential to manage SIBO.

Antibiotic therapy is typically used for a minimum of two weeks. Rifaximin is often used for hydrogen-SIBO, sometimes combined with other medications for different types. (1)

Herbal therapy may involve using two antimicrobial herbs together for at least four weeks. Oregano, berberine, and neem are commonly used for hydrogen-SIBO, with allicin sometimes added for IMO. (1)

The elemental diet is another option, providing nutrients while limiting bacterial growth.

SIBO Prevention

Preventing SIBO recurrence may involve using a prokinetic agent, like ginger, to support intestinal motility. Other strategies include managing underlying conditions, supporting digestive enzymes, and stress management. (1)

Nutrition for SIBO and Related Conditions

Dietary changes can help manage SIBO symptoms and support gut health.

The low-FODMAP diet is often used to manage SIBO and IBS symptoms by limiting certain carbohydrates. The goal is to reintroduce these foods once SIBO is managed.

After addressing SIBO, a whole-food, anti-inflammatory diet may support gut health, blood sugar stability, and overall well-being. The Mediterranean diet is one example of a diet that may support health.