Small intestinal bacterial overgrowth (SIBO) is a common gastrointestinal condition that may be burdening your irritable bowel syndrome (IBS) patients. The general treatment approach is to prescribe antibiotics or antimicrobial herbs to eradicate the overgrowth. The problem is that many clinicians stop there, and patients relapse. As with anything in functional medicine, we always want to look for underlying root causes and use comprehensive treatment approaches. Adjunctive treatment used for overall gut health is proving to be the best approach in SIBO management.
A randomized controlled trial published in the journal Nutrients studied the effects of herbal supplements and probiotics alongside antibiotics and a low FODMAPs diet for SIBO. 179 patients diagnosed with SIBO via breath testing were enrolled in the study. Patients received breath testing at the beginning and the end of the 3-month study. Patients were divided into hydrogen (H2) and methane (CH4) predominant groups, since treatment varies slightly depending on the breath gas type.
The control group followed a low Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) diet for 4 weeks and received 10 days of 1200 mg rifaximin for H2-positive, or rifaximin + 1000 mg neomycin for CH4-positive.
The intervention group completed the same protocol as the control group, but also received antimicrobial herbs, probiotics, and prebiotics. Each ingredient was chosen for its benefit in treating SIBO, correcting dysbiosis, supporting intestinal barrier integrity, and/or decreasing IBS symptoms. Treatment was separated into 2 phases:
- Phase 1 (eradication): Following the 10 days of prescriptive antibiotics, those with H2 received 20 days of capsules containing botanical oils (Origanum vulgare, Cinnamomum cassia, Citrus limon, Mentha piperita) as well as berberine. The patients with elevated CH4 received 20 days of the probiotic Saccharomyces boulardii and the botanical product, as well as a wormwood supplement. Minor adjustments were made to the protocols depending on tolerability, and some of the herbs were replaced with other products.
- Phase 2 (mucosal recovery): Both the H2 and CH4 groups received 6 weeks of a Bifidobacterium and Lactobacillus-based probiotic and 10 g L-glutamine. The H2 group also received 5 g of partially hydrolyzed guar gum. The rationale for including this prebiotic for the H2 group, but not the CH4 group, was that it was shown to improve stool consistency in diarrhea. Patients with CH4 tend more towards constipation.
The results showed improvement in GI symptoms and clinical remission rates in the intervention group, especially the CH4 group. There were no significant differences in the normalization of breath gases between the control group and the intervention group, suggesting that the addition of herbal antimicrobial supplements to standard treatment does not improve test results. Most clinicians either treat with the standard antibiotics or antimicrobial herbs or a combination, not both sequentially as in this study.
Because this study involved many variables, these results have multiple explanations. However, the bottom line is that adjunctive therapies resulted in greater clinical improvement.
Conclusions
Best practices for comprehensive SIBO management are evolving. Two recent reviews looked at the benefits of prebiotics, probiotics, and prokinetics as part of a comprehensive SIBO treatment program. Prokinetic agents were not used in this study, but are important following SIBO treatment to ensure proper motility, which is a risk factor for SIBO development. From my experience working at a lab that does SIBO breath testing, the clinicians who focus on overall gut health usually see the best results and are the most successful at preventing recurrence.
