SIBO Symptoms

Overgrowth in the small intestine can provoke bacteria to ferment and feed off undigested carbohydrates found in the foods we eat. A byproduct of this fermentation process includes hydrogen and methane gas production. In excess, these bacterial gases can provoke a variety of gastrointestinal symptoms including gas, bloating, abdominal pain, constipation, and diarrhea.^{8 9 10} 

 
Moreover, bacterial fermentation can lead to the production of toxic by-products that can irritate and damage the gut lining, promoting nutritional deficiencies and increased gastrointestinal permeability, also known as leaky gut.^{11 12} Leaky gut can allow undigested food particles, toxins, and bacteria to enter systemic circulation, provoking an immune response and subsequent inflammation. This can ultimately lead to the development of systemic issues including rosacea, food sensitivities/allergies, chronic fatigue syndrome, and autoimmune conditions such as fibromyalgia.^{13 14} In addition, excess bacteria can disrupt bile acids (compounds required for fat digestion) contributing to fat malabsorption and deficiencies in fat-soluble vitamins A, D, E, and K.¹⁵ Bacteria can also compete for nutrients such as iron and vitamin B12, consuming them before we have the chance to absorb them.¹⁶ 
 

Causes of SIBO

The body has many protective mechanisms to keep bacterial populations under control, including stomach acid, digestive enzymes, proper gut motility, and a robust gut immune system; but dysfunction in any of these antibacterial mechanisms can predispose the gut to dysbiosis and bacterial overgrowth.^{17 18} Unfortunately, several dietary and lifestyle factors can disrupt or impair these important protective barriers. For example, chronic stress has been shown to decrease stomach acid and digestive enzyme output, slow gut motility, and disrupt the gut immune system.^{19 20 21 22} Chronic use of acid lowering drugs like proton-pump inhibitors and pain medications may also slow gut motility, predisposing individuals to SIBO.^{23 24} Additionally, the Standard American Diet (SAD), high in refined sugars and carbohydrates, can disrupt a specific type of movement in our gut known as the migrating motor complex (MMC).²⁵ The MMC serves as the custodian of the gut, sweeping extra bits of food and bacteria down the small intestine and toward the exit, preventing stagnancy or buildup of bacteria.²⁶ 
 

Diagnosing SIBO

Breath testing is the most common procedure for diagnosing SIBO.²⁷ This typically involves consuming a carbohydrate-containing beverage (glucose, lactulose) and measuring exhaled levels of hydrogen and methane gas over a three-hour time period. Measuring the types and amounts of gases exhaled in the breath provides clinicians with a useful tool for diagnosing bacterial overgrowth. Additionally, the type of gas pattern produced can serve as a predictor of effects on bowel motility²⁸— hydrogen-dominant SIBO is associated with diarrhea-like symptoms, while those with methanedominant gas patterns are five times more likely to experience constipation.^{29 30 31} If considering breath testing, it is recommended that individuals work with a qualified practitioner who has experience in interpreting breath test results.    
 

SIBO Treatment

The treatment of SIBO requires a holistic approach that involves the induction of remission, and then the maintenance of remission, which includes treatment or modification of underlying causes.³² 
 

Induction of Remission

Current treatment of SIBO relies heavily on the use of broad-spectrum antibiotics. Antibiotics such as rifaximin and neomycin have proven efficacy in eliminating bacterial overgrowth. Specifically, across eight clinical trials, rifaximin demonstrated a SIBO eradication rate of 49.5 percent.³³ In addition, a retrospective study looking at twenty-seven methane-dominate SIBO patients found that a combination of neomycin plus rifaximin for ten days eliminated methane in 87 percent of subjects.³⁴ However, concerns have been raised among clinicians regarding the use of these antibiotics due to potential longlasting effects on the gut microbiome, including reduced beneficial flora and microbial diversity.³⁵ Thus, current research exploring more effective and safer therapeutic options is ongoing, especially with herbal antibiotics.

Preliminary research suggests that herbal antibiotics may be as effective as antibiotics in the treatment of SIBO. In a 2014 study looking at 104 newly diagnosed SIBO patients, researchers compared the use of rifaximin versus herbal antibiotic therapy in the resolution of SIBO. Of these patients, 37 received herbal therapy while 67 received rifaximin. Results of the study revealed that after four weeks of treatment, 45 percent receiving herbal therapy and 34 percent receiving rifaximin successfully eradicated SIBO. Overall, eradication rates between the two groups did not reach statistical significance, indicating that herbal therapy was at least as effective as rifaximin.³⁶

Herbal Antibiotics for SIBO Treatment 

Due to their strong antibacterial properties, several herbal antibiotics including berberine, allicin (garlic extract), and neem are commonly used in the treatment of SIBO.³⁷ Dosing Recommendations: Most often, herbal antimicrobials are used as single agents or in various combinations for a 30-day period at doses that are at the upper limit of label suggestions. Single doses include allicin extract 450mg, 2-3 times daily; berberine 5g, in divided doses; and neem 300mg, three times daily.³⁸ 

Additional Supplements for SIBO Treatment

AtrantilTM, a product that includes three naturally derived ingredients including quebracho extract, conker tree, and peppermint, is another natural antimicrobial to consider. Quebracho extract contains tannins that soak up excess hydrogen and methane gas and disrupt and destroy bacterial lipid layers. In addition, antimicrobial agents known as saponins in conker tree have been shown to directly reduce methane production and emission.³⁹ Dosing Recommendations: Recommended to begin dosing at two capsules, three times daily with food.⁴⁰ 
 

Diet during SIBO Treatment

Lower carbohydrate diets such as the low-FODMAP or the Specific Carbohydrate Diet (SCD) are often recommended during SIBO treatment. Since bacteria rely on carbohydrates as their primary fuel source, it is thought that restriction of these dietary compounds starves bacteria, supporting their elimination. However, formal studies to validate this are lacking and research suggests that including carbohydrates, especially prebiotic fibers, alongside SIBO treatment may be more effective in eliminating overgrowth. For instance, a 2010 study revealed that a combination of rifaximin with partially hydrolyzed guar gum (a prebiotic fiber) was more effective than rifaximin alone in eradicating SIBO.⁴¹ 
 

Maintenance of Remission

Even when antibiotics or herbal antibiotics are successful, relapse is common. In a 2008 study looking at eighty SIBO patients successfully treated with rifaximin (1,200mg/day for 1 week), 12.6%, 27.5%, and 43.7% of subjects experienced relapse by three, six, and nine months, respectively, following treatment.⁴²  
 
That said, strategies that support the maintenance of remission following treatment are indicated. This includes implementing agents that support or replace the body’s natural antimicrobial mechanisms, including stomach acid, digestive enzymes, and proper motility, which are commonly disrupted in those with SIBO.⁴³ 
 

Supplements following SIBO Treatment

Adequate stomach acid is needed to kill off any ingested bacteria and to prevent bacteria from entering the small intestine. Various factors including stress, age, and chronic use of acid-lowering medications can decrease stomach acid. Supplements such as digestive bitters and betaine HCL can support adequate stomach acid levels, thus supporting overall microbial balance. Dosing Recommendations: Please see our CLF Acid for Digestion.    Additionally, adequate pancreatic digestive enzymes not only help to digest food, but also support a healthy and balanced gut microflora. In a 2018 mouse study, supplementation with pancreatic enzymes supported the normal colonization of beneficial bacteria within the gut including Lactobacillus reuteri.⁴⁴ L. reuteri has been shown to modulate inflammation in the gut and to support gut barrier integrity.⁴⁵ Digestive enzymes may also assist in the breakdown of biofilms formed by methane producers, which are tightly packed collections of microbes that can adhere to the lining of the small intestine.⁴⁶ Dosing Recommendations: Consider taking pancreatic enzymes containing lipase, protease, and amylase with main meals. Follow dosing recommendations on the bottle. 
 
Gut motility, including MMC activity, may also be disrupted in those with SIBO.⁴⁷ Supplements such as ginger and 5-HTP can support a healthy MMC. In one study, intake of ginger extract while fasting supported greater activity during the most active phase of the MMC.⁴⁸ Additionally, by serving as a precursor to serotonin, which is heavily involved in gut motility, 5-HTP can support activation of the MMC.⁴⁹Dosing Recommendations: Consider 200mg ginger extract at bedtime or immediately upon waking or 100-200mg 5-HTP. 

Diet following SIBO Treatment.

Once the overgrowth is eradicated and symptoms subside, diet should focus on wholesome, natural, and organic foods that emphasize restoration of the gut microbiome.50 This includes removal of excess sugar, artificial sweeteners, and preservatives, which can contribute to dysbiosis. If well tolerated, diet should also focus on implementation of microbiome-restorative foods such as prebiotic-rich (Jerusalem artichokes, dandelion roots, garlic, onion, leeks), fermented (kimchi, sauerkraut, yogurt), polyphenol-rich (blueberries, raspberries, purple carrots, purple/red potatoes, olive oil), and high fiber, whole-plant foods. One might also consider the addition of microbiome-restorative supplements such as probiotics, prebiotics (fructooligosaccharides, inulin), and other gut-supportive nutrients like curcumin and omega-3’s. For more information on gut-supportive nutrients, please refer to our CLF Probiotics – Microbiome Nutrients. If symptoms continue to persist, consider retesting for SIBO to ensure complete eradication of the overgrowth. A more targeted dietary approach, monitored by a trained nutrition professional, may also be necessary to rule out additional food sensitivities that could be contributing to continual symptoms.  
 
 
 

References Available Upon Request