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By KARA FITZGERALD, ND, IFMCP, and Lara Zakaria, RPh, MSc, CNS, CDN, IFMCP

SIBO Basics

Awareness of small intestinal bacterial overgrowth (SIBO) has increased in recent years, in part as relatively common risk factors have become more widely recognized. For instance, low stomach acid (including from PPI use), pancreatic insufficiency, irritable bowel syndrome (IBS) and Crohn’s, celiac diagnosis, and diabetes all raise the risk of SIBO.¹

Despite its prevalence, SIBO can be challenging to diagnose. SIBO sufferers often describe a range of agonizing gastrointestinal (GI) symptoms, including:²

• Abdominal distension
• Flatulence
• Cramping
• Diarrhea
• Constipation

Non-GI symptoms attributed to SIBO include systemic symptoms like brain fog, headaches, fatigue, skin conditions, and joint pain.^3-5

Interventions focus on the primary pathophysiology, which includes dysbiosis, altered GI motility, hypochlorhydria, reduced production of digestive enzymes, osmotic pressure, fermentation, and nutrient depletion due to malabsorption and maldigestion along with altered local and/or systemic immunity and intestinal permeability.^2,6-7

The mainstay of SIBO treatment is antimicrobial therapy (prescriptive and herbal),^2,5 although one study suggests recurrence of infection may be common.⁸ Additionally, used solo, antibiotics are insufficient for addressing the full spectrum of underlying pathologies.^6,10

Elimination Diet and Other Nutritional Considerations

In our clinic, we emphasize safe, nutrient-dense therapeutic foods with anti-inflammatory, antioxidant, and phytonutrient properties. An elimination diet can remove problematic foods contributing to local inflammation while reducing FODMAPs, starches, and sugars, which aggravate GI symptoms.⁶

In the context of an elimination diet, specific foods can help these patients. Therapeutically beneficial healthy fats should be leveraged, including medium-chain triglycerides (MCTs), omega-3 sources, and butyric-acid and vitamin A–rich ghee. Bone broth is rich in L-glutamine and can help satiate and provide added minerals and collagen support to heal hyperpermeability.¹¹ Due to the nature of the pathophysiology, supplementation is usually necessary to enhance micro/macronutrient status,² and we often use the following:

• Digestive enzymes
• Betaine HCL titration
• A multivitamin with attention to fat-soluble vitamins and B12

Ideally, nutrient supplementation is informed by advanced nutrient testing to cover any nutritional gaps.

Certain prebiotic sources have been shown to be helpful; however, tolerance varies. Therefore, we implement prebiotics cautiously as they may contribute to GI distress, activation of inflammatory response, and non-compliance.⁴ For the same reasons, fermented foods and probiotics are generally not tolerated.⁴ Fructooligosaccharides (FOS) and inulin are common prebiotics that are not well-tolerated, but low-FODMAP fruits, vegetables, and sources of hydrolyzed guar gum or psyllium are better tolerated and contribute to improving antimicrobial efficacy.¹²

Migrating Motor Complex Support

Support of the migrating motor complex (MMC) is essential; therefore, it’s important to integrate mindful eating, careful chewing, meditation, and pre-meal breathing and gratitude practice. Additionally, singing and gargling exercises have been shown to support MMC activation.^13-14

Meal timing strategies can be leveraged to ameliorate GI discomfort. Meal spacing and intermittent fasting might be beneficial for some with slow bowel motility. Furthermore, therapeutic herbs such as Swedish bitters, bitter greens, ginger, and fennel seeds might also be useful.¹⁵

Final Considerations

Due to the complexity and risk for nutritional inadequacy, the Elimination Diet should be followed under careful supervision of a nutritionist.⁶ Furthermore, this should be considered a temporary intervention meant to be followed by a careful reintroduction as soon as is safely tolerated to diversify the diet, and to prevent unnecessary restriction and potential hyperreactivity. Symptom tracking during the process of careful challenge can help the clinician evaluate protocol success and guide on next steps in treatment.

Finally, in refractory SIBO cases, using an elemental diet alone, or with a few carefully selected, well-tolerated foods can be useful as a first step or for periodic intervention for rapid symptom relief.¹⁶ In our clinic, we have noted a rise in the number of patients presenting with SIBO who have failed antibiotic monotherapy or suffer from relapse as a result. Augmenting antibiotic therapy with a nutrition strategy that addresses all underlying pathologies can greatly improve results, prevent recurrence, and restore health.

View Kara Fitzgerald’s Practitioner-Focused Blog

References

1. Bures J, Cyrany J, Kohoutova D, et al. Small intestinal bacterial overgrowth syndrome. World J Gastroenterol. 2010;16(24):2978-2990. doi:3748/wjg.v16.i24.2978
2. Adike A, DiBaise JK. Small intestinal bacterial overgrowth: nutritional implications, diagnosis, and management. Gastroenterol Clin North Am. 2018;47(1):193-208. doi:1016/j.gtc.2017.09.008
3. Pimentel M, Wallace D, Hallegua D, et al. A link between irritable bowel syndrome and fibromyalgia may be related to findings on lactulose breath testing. Ann Rheum Dis. 2004;63(4):450-452. doi:1136/ard.2003.011502
4. Rao SSC, Rehman A, Yu S, Andino NM. Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis. Clin Transl Gastroenterol. 2018;9(6):162. doi:1038/s41424-018-0030-7
5. Chedid V, Dhalla S, Clarke JO, et al. Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth. Glob Adv Health Med. 2014;3(3):16-24. doi:7453/gahmj.2014.019
6. Bohm M, Siwiec RM, Wo JM. Diagnosis and management of small intestinal bacterial overgrowth. Nutr Clin Pract. 2013;28(3):289-299. doi:1177/0884533613485882
7. Grover M, Kanazawa M, Palsson OS, et al. Small intestinal bacterial overgrowth in irritable bowel syndrome: association with colon motility, bowel symptoms, and psychological distress. Neurogastroenterol Motil. 2008;20(9):998-1008. doi:1111/j.1365-2982.2008.01142.x
8. Lauritano EC, Gabrielli M, Scarpellini E, et al. Small intestinal bacterial overgrowth recurrence after antibiotic therapy. Am J Gastroenterol. 2008;103(8):2031-2035.
9. Quigley E. Small intestinal bacterial overgrowth: what it is and what it is not. Curr Opin Gastroenterol. 2014;30(2):141-146. doi:1097/MOG.0000000000000040
10. Rezaie A, Pimentel M, Rao SS. How to test and treat small intestinal bacterial overgrowth: an evidence-based approach. Curr Gastroenterol Rep. 2016;18(2):8. doi:1007/s11894-015-0482-9
11. Wang B, Wu G, Zhou Z, et al. Glutamine and intestinal barrier function. Amino Acids. 2015;47(10):2143-2154. doi:1007/s00726-014-1773-4
12. Furnari M, Parodi A, Gemignani L, et al. Clinical trial: the combination of rifaxin with partially hydrolysed guar gum is more effective than rifaximin alone in eradicating small intestinal bacterial overgrowth. Aliment Pharmacol Ther. 2010;32(8):1000-1006. doi:1111/j.1365-2036.2010.04436.x
13. Pimentel M, Soffer EE, Chow EJ, Kong Y, Lin HC. Lower frequency of MMC is found in IBS subjects with abnormal lactulose breath test, suggesting bacterial overgrowth. Dig Dis Sci. 2002;47(12):2639-2643. doi:1023/a:1021039032413
14. Miyano Y, Sakata I, Kuroda K, et al. The role of the vagus nerve in the migrating motor complex and ghrelin- and motilin-induced gastric contraction in suncus. PLoS One. 2013;8(5):e64777. doi:1371/journal.pone.0064777
15. Depoortere I. Taste receptors of the gut: emerging roles in health and disease. Gut. 2014;63(1):179-190. doi:1136/gutjnl-2013-305112
16. Pimentel M, Constantino T, Kong Y, Bajwa M, Rezaei A, Park S. A 14-day elemental diet is highly effective in normalizing the lactulose breath test. Dig Dis Sci. 2004;49(1):73-77. doi:1023/b:ddas.0000011605.43979.e1