SIBO: Comorbidities, SIFO, and Diagnosis

A healthy intestinal microbiome is essential for optimal immune function and wellness. Microbial overgrowth in the small intestine has been associated with several health issues and may be caused by many factors. Small intestinal bacterial overgrowth (SIBO), specifically, is a condition that presents with a range of detrimental gastrointestinal (GI) and non-GI-related symptoms and is associated with diverse comorbid conditions. Restoring balance to gut flora through individualized interventions and tailored treatments that address lifestyle factors and nutritional needs may dramatically improve health.

In this video, IFM educator Thomas Sult, MD, IFMCP discusses nutritional therapies and modifiable food plans that may be appropriate for patients with SIBO.

SIBO comorbidities

Research results have suggested links between SIBO and diseases such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), motility disorders, chronic pancreatitis, cirrhosis, and various immunodeficiency syndromes.^1,2 Specific to IBS, a 2020 systematic review and meta-analysis examined 25 case-controlled studies with a total of 3,192 IBS patients and 3,320 controls and found that SIBO prevalence in patients with IBS was significantly increased.³

In addition, smaller studies have found that SIBO is more frequently present in populations with active H. pylori infection⁴ and spinal cord injury with deep vein thrombosis,⁵ and is also associated with pediatric obesity,⁶ papulopustular rosacea,⁷ and nonalcoholic fatty liver disease (NAFLD) at a higher rate than controls. In a small study of obese children with SIBO, researchers found an increased risk for developing NAFLD.⁸ The study concluded that the relationship between intestinal dysbiosis and diet can influence the gut-liver axis.⁸ In an interesting contrast, researchers found a lower prevalence of SIBO in patients with type 1 diabetes and suggested this may be due to nutritional interventions in the management of the disease.⁹

Considering the fungal component

Within a healthy GI tract, bacterial and fungal organisms most heavily colonize the colon, while these microbial communities appear less in the small intestine. As with SIBO, small intestinal fungal overgrowth (SIFO) may lead to various systemic symptoms such as migraines, fatigue, depression, bloating, and more.¹⁰ Also like SIBO, intestinal dysmotility and reduced amounts of stomach acid resulting from PPI use are potential risk factors specifically for SIFO.^1,11-13