By: Elise Chmielewski (intern) and Orli Rabin of ThrivingBiome October 2024
You may have heard the term SIBO before; it’s an acronym that gets used a lot, but what does it actually mean? SIBO stands for Small Intestinal Bacterial Overgrowth. Unlike the large intestine, the small intestine should not contain large amounts of bacteria. When an overgrowth occurs in the small intestine, invasive strains of bacteria can damage the gut lining, resulting in uncomfortable digestive symptoms.
Common symptoms of SIBO include:
Bloating
Diarrhea
Constipation
Gas
Fullness
Abdominal pain or cramps
SIBO can also lead to improper absorption of nutrients, particularly vitamin B12 and D deficiencies, and weight loss. Because the gut plays many more roles than just digestion, fatigue, headaches, chronic inflammation, weakened immune system, and skin conditions are also symptoms that can occur secondary to GI distress.
What causes SIBO?
The reasons behind the development of SIBO are complex. Some causes include low stomach acid, inadequate digestive enzymes, slow peristalsis (muscle contractions that move food and liquids throughout the digestive tract), or malfunctioning ileocecal valve (controls flow of food between small and large intestine).
Slow peristalsis and a malfunctioning ileocecal valve inhibit proper gut motility. When food is not being moved from one part of the gut to the next in a timely manner, certain food particles stay stagnant and ferment. This causes gastrointestinal symptoms and discomfort.
How can I know if I have SIBO?
Conventional Testing Options
The gold standard test for SIBO is an endoscopy, a procedure where a long, thin tube is inserted through the mouth into the small intestine to obtain a sample of intestinal fluid. Due to the invasive and potentially complicated nature of this procedure, the more common method of testing is a breath test. In some cases, imaging tests like CT scans or MRIs might be used to look for structural abnormalities in the intestine that could contribute to SIBO.
The breath test involves drinking a carbohydrate solution, then collecting multiple breath samples continuously over a period of time (usually 90 minutes). This test is able to detect high levels of hydrogen or methane gasses in the breath. If the carbohydrate is fermented by excess bacteria in the small intestine, higher levels of these gasses will be produced and excreted through the breath.
Alternatively, the GI-MAP, which is more traditionally used by functional medicine practitioners, can be used to give us clues of bacterial overgrowth.
The GI-MAP provides a detailed look at your digestive capacity and offers insights into both opportunistic and commensal bacterial colonies in the gut. By identifying imbalances or specific bacterial overgrowths, we can tailor your protocol to support optimal digestion, address underlying bacterial imbalances, and restore healthy gut function more effectively. Here are a few sample pages a practitioner might focus on when suspecting SIBO:
Some of the most common bacterial strains we look at on the GI-MAP to help determine if SIBO might be present include elevated levels of Enterococcus spp., Bacillus spp., Morganella spp., and Methanobacteriaceae (family). We also dive deep into intestinal markers and look at h pylori levels as these typically impact stomach acidity levels.
Approaches for Combating SIBO
There are conventional, dietary and functional medicine approaches for SIBO:
Conventional Approaches
Conventional treatments typically include antibiotic use and sometimes take into account dietary changes, but this is very provider dependent.
Rifaximin and neomycin are the most common antibiotics prescribed for the treatment of SIBO. However, it’s important to note that approximately 45% of patients will have recurrent SIBO following antibiotic treatment. Moreover, antibiotics can negatively impact protective bacterial colonies in the gut and don't account for the root reason someone developed bacterial overgrowth in the first place.
Dietary Approaches
The low FODMAP diet (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols) can be a temporary strategy for symptom relief. This diet eliminates indigestible or poorly absorbed carbohydrates that cause discomfort in those suffering from SIBO.
In more severe cases, the elemental diet might be used. The elemental diet is a liquid diet that contains pre-digested nutrients for patients who cannot tolerate or fail to respond to antibiotics. It may be used in place of some or all meals. The elemental diet contains no fiber and gives the gut a break from digesting food. It can also aid in decreasing inflammation and repairing the gut lining. This is a pretty extreme approach that we would generally only recommend as a last resort if symptoms are unbearable and other treatment modalities fail to provide relief.
Functional Medicine Approaches
Functional medicine approaches to eliminate and prevent Small Intestinal Bacterial Overgrowth (SIBO) focus on addressing the root causes, improving gut function, and restoring balance in the gut microbiome. Here are some key steps:
1. Address Underlying Causes
Motility Support: One of the primary causes of SIBO is impaired gut motility. Functional medicine practitioners often focus on improving the migrating motor complex (MMC), the gut's "clean-up" wave between meals. This can include using prokinetics like ginger, 5-HTP, or motility-enhancing supplements.
Stomach Acid and Digestive Enzyme Support: Low stomach acid (hypochlorhydria) and enzyme deficiencies can contribute to SIBO by allowing bacteria to thrive in the small intestine. Supplementing with digestive enzymes or betaine HCl may help. We use the GI-MAP to determine need.
Address Structural Issues: If there are structural problems (e.g., adhesions, bowel surgery, or strictures) causing stagnation, manual therapy like visceral manipulation can be helpful.
2. Antimicrobial Treatment
Herbal Antibiotics: Oregano oil, berberine, garlic, and neem are commonly used to target bacterial overgrowth. These herbs tend to have fewer side effects than pharmaceutical antibiotics. In some cases, the use of antibiotics might be necessary to use in conjunction to herbals; this is highly individualized and generally avoided whenever possible.
3.Dietary Approaches
Processed Sugars: Sugars and certain carbohydrates act as food for the bacteria. Fine-tuning the diet and reducing or removing added sugars and refined carbohydrates may temporarily relieve symptoms.
Meal Timing: Spacing meals by 4-5 hours without snacking between them can allow the migrating motor complex to work more effectively, helping to clear bacteria from the small intestine.
Chewing Thoroughly + Mindfully: Proper mastication supports digestion and reduces the burden on the small intestine. Eating mindfully and without distraction (watching TV, doing work, scrolling on social media, etc.) is optimal for proper digestion, as it propels the nervous system towards a parasympathetic (“rest and digest”) state. Additionally, taking 3-4 deep, diaphragmatic breaths (filling the entire stomach area with air rather than shallow, chest breathing) prior to eating can help reduce stress and calm the GI tract.
4. Gut Barrier Support
L-Glutamine, Zinc Carnosine, and Bone Broth: These supplements and foods support gut lining repair, reducing inflammation and preventing bacterial translocation across the gut barrier. However, timing for supplementation is crucial. Steps 1-3 on this list should be addressed prior to implementing supplements to ensure optimal benefits.
Colostrum or Immunoglobulin Support: To enhance mucosal immunity and reduce immune reactivity to bacterial overgrowth.
*We don't recommend using these without testing first, and talking with a provider.
5. Restore Healthy Gut Flora
Probiotics (with caution): While probiotics like Saccharomyces boulardii and certain strains of Lactobacillus and Bifidobacterium can help balance the gut microbiome, some patients with SIBO react poorly to them. It’s often recommended to wait until after SIBO treatment to introduce probiotics or to use spore-based probiotics, which tend to be better tolerated.
Prebiotics: Once SIBO is under control, prebiotic fibers (like partially hydrolyzed guar gum or inulin) can help restore healthy bacteria in the colon.
6. Stress Management and Nervous System Support
Mind-Body Techniques: Chronic stress can impair digestion and reduce gut motility. Incorporating stress reduction practices like mindfulness, meditation, deep breathing, or yoga can support the healing process.
Nervous System Regulation: We refer all SIBO clients to a nervous system practitioner to help calm the sympathetic nervous system and promote parasympathetic activity, which is vital for proper digestive function and motility. some text
Nervous system regulation can involve techniques such as vagus nerve stimulation. The vagus nerve is a critical part of the parasympathetic nervous system and establishes a connection between the brain and the gastrointestinal tract. Strengthening this nerve through diaphragmatic breathing, yoga, or mediation may benefit gut function.
7. Long-Term Prevention
Maintenance with Prokinetics: To prevent recurrence, low-dose prokinetics like ginger, Iberogast, or certain medications (like low-dose erythromycin) may be recommended to keep gut motility functioning well.
Regular Gut Health Check-Ups: Periodic testing for gut health markers (like the GI-MAP or repeat SIBO breath tests) to ensure that balance is maintained.
As you can see, this comprehensive, individualized approach is aimed at not only eliminating SIBO but also preventing relapse and promoting overall gut health. If you think you may have symptoms of SIBO or are interested in learning more, schedule a consultation here.
2. Redondo-Cuevas L, Belloch L, Martín-Carbonell V, et al. Do Herbal Supplements and Probiotics Complement Antibiotics and Diet in the Management of SIBO? A Randomized Clinical Trial. Nutrients. 2024;16(7):1083. Published 2024 Apr 7. doi:10.3390/nu16071083
