SIBO: Build Back Your Digestive Defenses
Dr. Eric Viegas, ND
Our microbiome is the collection of microbes, in and on our bodies, that offer a mutual benefit. The health of our microbiome dictates our overall health status. Human cells that compose us are dwarfed by the number and variety of microbes those cells house. Our microbiota, the friendly microbes in our gut, help to digest food, strengthen our immune system, defend our intestines from unfriendly bacteria, and heal our gut (Gerritsen et al., 2011). The balance of our individual microbiota lies in a complex relationship between our genetics, diet, environment, and even our social circles. Our microbiota is one of the numerous defense systems our bodies use to keep out unwanted organisms from the small intestine. When one or more of these systems fail, an overgrowth of unfriendly microbes is possible.
We secrete stomach acid and pancreatic enzymes to better digest our food, but our bodies also use it as a safeguard against unwanted microorganisms. When poor stomach acid secretion fails to defend against colonies of foreign microbes, an overgrowth of these bacteria in the small intestine leads to an imbalanced microbiota. In addition, digestive tract abnormalities, abdominal surgery complications, and impaired gallbladder & pancreatic function can allow overgrowth of foreign microbes that disturb the balance of our microbiota.
Impaired migrating motor complexes (MMC) also set the stage for foreign bacteria to colonize the small intestine (Miyano et al., 2013). MMC initiates peristalsis, the muscular contraction of our intestines that moves food through the gut into the colon. MMC also occurs in a fasting state and acts to sweep unfriendly bacteria into the colon, limiting SIBO (Deloose et al., 2012). The vagus nerve controls MMC during parasympathetic nervous system activity (our rest and digest functions). The strength and conditioning of the vagus nerve (‘vagal tone’) also dictates our heart rate and breathing rate. Variation of our heart rate and breathing rate, known as respiratory sinus arrhythmia (RSA), can improve the efficiency of the cardiovascular and digestive systems. RSA is more significant in children and athletes than the elderly. Also, RSA is associated with better mental health and positive social interactions. Vagal tone is enhanced through RSA by practicing yoga (Streeter et al., 2010). Interestingly, deep laughter also stimulates the vagus nerve, causing RSA (Miller et al., 2009). Like to sing in the shower? Singing and making music also enhances RSA and vagal tone (Vickhoff et al., 2013).
What about SIBO and its relation to IBS?
IBS patients that do not improve with conventional IBS treatments are often diagnosed with SIBO. Long-standing MMC problems result in impaired peristalsis and dysbiosis. IBS patients with SIBO require digestive support coupled with eradication of bacterial overgrowth (Ghoshal et al., 2016). SIBO symptoms overlap with the gas, bloating, diarrhea, constipation, and abdominal pain that is common in IBS. It is estimated that more than half of all IBS patients have SIBO, and about half of all celiac cases also have SIBO (O’Leary, 2003). In celiac disease and SIBO, intestinal inflammation and permeability cause problems with nutrient absorption in the small intestine. As a result, patients are typically deficient in iron and vitamin B12; nutrients that are absorbed in a healthy small intestine. A lack of MMC also affects the secretion of bile for the digestion and absorption of fats and fat soluble vitamins (A,D,E,K) in the small intestine (Simren et al. 2006). In SIBO, some bacteria also digest bile before we can use it, further contributing to fat and fat soluble vitamins ending up in stool (Miyano et al., 2013). Weight loss due to malnutrition is a common symptom in long standing celiac disease and SIBO.
...IBD (Crohn’s Disease and Ulcerative Colitis) and SIBO?
Complicated cases of crohn’s disease require surgery to remove the ileocecum, a junction point in your digestive system between the small and large intestine. The ileocecal valve sits between the ileum of the small intestine, and the cecum of the large intestine. Though not a true ‘valve’, a healthy ileocecal valve successfully separates the colonies of microbes native to the large intestine from microbes of the small intestine. Once the ileocecum is surgically removed, so is the defense system that prevents colonic bacteria from entering the small intestine, and SIBO occurs. Other abdominal surgeries can also impair MMC.
In fact, there are a whole host of conditions that can lead to, or are caused by, SIBO. Any disease state that alters immune function, creates dysbiosis, and/or affects the MMC sets the stage for bacterial overgrowth. Since bacteria can squander bile acids needed for digestion and absorption of fats, the initial breath test for SIBO was the bile acid breath test. Bile acid breath testing fell out of favour, and now hydrogen and methane breath tests are used in the diagnosis of SIBO (Ghoshal, 2016). Patients are instructed to fast, then consume a lactulose or glucose drink. If SIBO is present, bacteria in the small intestine will begin to digest the sugars into hydrogen and methane before the expected colonic bacteria do the same. The reliability of breath testing for SIBO has been questioned due to the variability in normal and abnormal results (Simren et al., 2006). Though, if a positive breath test is present with diarrhea, weight loss, and malnutrition, doctors will treat presumptively. Depending on which gas scored higher on the breath test, doctors will prescribe antimicrobials specific to hydrogen or methane producing bacteria (or a combination).
So what can you eat to cut down on methane and hydrogen producing bacteria?
In terms of dietary recommendations for SIBO, there is no one size fits all approach. The FODMAPs diet, Specific Carbohydrate Diet (SCD), or Gut and Psychology Syndrome diet (GAPS) may work for some patients, but not others. It is important to identify your own individual food triggers. Sometimes a combination of the previously mentioned diets is what works for patients. An interesting treatment principle when dealing with SIBO is that well fed bacteria are easier to eradicate. So, eating food triggers that cause bacteria to ferment carbohydrates will lead to more efficient eradication using antibiotics and antimicrobials (Chedid et al., 2014). Once bacteria levels and SIBO symptoms are reduced, patients enter a recovery phase to rest and replenish the gut. Certain strains of probiotics can alleviate SIBO after short term therapy, and it is important to speak with your doctor about which strains are most appropriate for you (Kwak et al. 2014).
What are some ways to help manage SIBO in my day to day?
Successful treatment of SIBO, as with any chronic disease, relies on a holistic focus. Equal emphasis should be placed on eradicating bacteria, repopulating with probiotics, restoring vagal tone/MMC, avoiding food triggers, and healing the gut. Also, Exercise can improve digestive functions by enhancing MMC. Above all, patients should know that the road to recovery will never be linear, relapses often happen (Grover et al., 2008). Understanding mental-emotional health as an overarching goal will help give a big-picture context to patients, and build defenses against stress. Awareness of the connection between our mind and body is what will lead to building back digestive defenses. It’s no wonder that a relaxed state and laughter improves digestion. Finding enjoyment in exercise will also lead to improvements in MMC (Soffer et al., 1991). Finding something that brings you joy, something that leads you to more self-expression, is what will lead to a truly meaningful change. Rest and Digest!
For more information on SIBO: sibocenter.com
Gerritsen J., Smidt H., Rijkers GT., de Vos WM. Intestinal microbiota in human health and disease: the impact of probiotics. Genes Nutr 6; (2011): 209-240. Print.
Miyano Y, et al. “The role of the vagus nerve in the migrating motor complex and ghrelin-and motilin-induced gastric contraction in suncus.” PloS one 8.5 (2013). Web.
Deloose, Eveline, Pieter Janssen, Inge Depoortere, and Jan Tack. “The Migrating Motor Complex: Control Mechanisms and Its Role in Health and Disease.”Nature Reviews Gastroenterology & Hepatology 9.5 (2012): 271-85. Web
Streeter, Chris C., Theodore H. Whitfield, Liz Owen, Tasha Rein, Surya K. Karri, Aleksandra Yakhkind, Ruth Perlmutter, Andrew Prescot, Perry F. Renshaw, Domenic A. Ciraulo, and J. Eric Jensen. “Effects of Yoga Versus Walking on Mood, Anxiety, and Brain GABA Levels: A Randomized Controlled MRS Study.” The Journal of Alternative and Complementary Medicine 16.11 (2010): 1145-152. Web.
Miller, Michael, and William F. Fry. “The Effect of Mirthful Laughter on the Human Cardiovascular System.” Medical Hypotheses 73.5 (2009): 636-39. Web.
Vickhoff B, Malmgren H, Astrom R, Nyberg G, Ekstrom S-R, Engwall M, et al. “Music structure determines heart rate variability of singers.” Frontiers in Psychology Auditory Cognitive Neuroscience 334.4 (2013): 1-16. Web.
Ghoshal, Uday C., et al. “A proof-of-concept study showing antibiotics to be more effective in irritable bowel syndrome with than without small-intestinal bacterial overgrowth: a randomized, double-blind, placebo-controlled trial.” European journal of gastroenterology & hepatology (2016).
O’leary, C. “Small Bowel Bacterial Overgrowth, Celiac Disease, and IBS: What Are the Real Associations?” The American Journal of Gastroenterology 98.4 (2003): 720-22. Web.
Simren M, Stotzer P-O. “Use and abuse of hydrogen breath tests.” Gut 55.3 (2006): 297-303. Web.
Ghoshal, Uday C. “Overview of Hydrogen Breath Tests in Gastroenterology Practice.” Evaluation of Gastrointestinal Motility and Its Disorders (2016): 87-94. Web.
Chedid, Victor, et al. “Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth.” Global Advances in Health and Medicine 3.3 (2014): 16-24.
Kwak DS, Jun DW, Seo JG, Chung WS, Park SE, Lee KN, et al. “Short-term probiotic therapy alleviates small intestinal bacterial overgrowth, but does not improve intestinal permeability in chronic liver disease.” Eur J Gastroenterol Hepatol 26.12 (2014): 1353-1359. Web.
Grover, Madhusudan, et al. “Small intestinal bacterial overgrowth in irritable bowel syndrome: association with colon motility, bowel symptoms, and psychological distress.” Neurogastroenterology & Motility 20.9 (2008): 998-1008.
Soffer EE, Sumers RW, Gisolfi C. “Effect of exercise on intestinal motility and transit in trained athletes.” Am J Physio 5.1 (1991): 698-702. Web.