There is so much data coming out about the “gut microbiome” and its complex ecosystem (what we call the delicate symphony of good and bad bacteria). One of the primary conditions that has received a lot of attention in the last decade, and often associated with IBS, is what we call “SIBO (small intestinal bacteria overgrowth).
SIBO is a condition characterized by the atypical growth of bacteria in the small intestine.1 The large intestine normally has high levels of bacteria, but the small intestine should be virtually free of bacteria by comparison. Bacteria in the small intestine, in the presence of certain dietary carbohydrates from common food sources, ferment these sugars into gas. Through this production of gas, as well as the breakdown of bile salts, SIBO can wreak havoc on our digestive system.
SIBO is a common disorder thought to affect between 3-30% of the general population. In one study, about 60% of children, presenting with abdominal pain, were found to have the presence of SIBO.2 The most common causes are due to impaired gastrointestinal motility, which can be causes by a food poisoning event (i.e. post-infectious gastroenteritis), medications (antibiotics), stress, genetics, and poor digestive function, can also play a significant role in developing SIBO.
One of the biggest challenges with SIBO is that many bacteria that cause this condition are “normal” residents of our intestines. However, due of impaired motility and other contributing factors mentioned above, these otherwise “healthy” bacteria are found to overgrow in the small intestine, resulting in SIBO.
Bacterial overgrowth in the small intestine predominately produces 2 gases: hydrogen and methane. Excess production of hydrogen gas is the most common form of SIBO and levels of hydrogen gas measured in some people can be very high, contributing to most of the symptoms of SIBO (listed below). Methane gas production from bacteria, called methanogens, is the second most common form of SIBO. Methane-based SIBO is very strongly correlated to “sluggish bowels” or constipation, and methane gas is thought to disrupt motility in the small and large intestine. Research shows people harboring methane producing bacteria have delayed emptying of the colon.6-10
WHAT ARE SYMPTOMS OF SIBO?
Symptoms of SIBO are commonly non-specific; subsequently, diagnosis can be quite challenging. Some of the most common symptoms include:
Gas and Bloating
Because the gut microbiome is what I like to say “the center of the universe” in our body, I often find hormonal dysfunction, anxiety, sleep disturbance, acne, and even autoimmune conditions can be connected to SIBO due to dysbiosis in the gut. SIBO has either been found to cause or associate with many other medical conditions. The reason for this is because SIBO can affect our absorption of nutrients and affect our immune system.
WHAT ARE THE LONG-TERM EFFECTS OF SIBO IF LEFT UNTREATED?
The long-term effects of SIBO include anemia, which can develop through a variety of mechanisms. The production of red blood cells is particularly sensitive to nutritional malabsorption, since iron is primarily absorbed by the first parts of the small intestine, primarily the duodenum and jejunum. The malabsorption of iron can cause red blood cells to be smaller than normal, a condition known medically as microcytic anemia.
SIBO can also result in the malabsorption of vitamin B-12, which normally occurs in the last part of the small intestine, or ileum. This type of malnutrition can cause many conditions, including large red blood cells, or megaloblastic anemia. Older adults with chronic SIBO also have a lower body mass index, a higher rate of diarrhea and a lower level of serum albumin.
HOW DO I KNOW IF I HAVE SIBO?
A breath test (which is most often covered by insurance) is the simplest, easiest and most cost-effective way to determine if you have SIBO. It is non-invasive test that you perform at home. The testing involves completing a fast, drinking a lactulose solution (a dairy-derivative) and collecting breath samples into a collection device. The lab then analyzes the sample for the presence of methane and hydrogen gas.
HOW DO I GET RID OF SIBO?
There are many options for that are effective for treating SIBO, including herbs and various medications, dietary changes, stress management, and sometimes re-education of the nervous system (i.e. vagus nerve) to support the migratory motor complex (essentially the broom of the digestive tract), when the gut is not performing optionally. Oftentimes, it is a multi-system approach (i.e. treating thyroid or other hormone disruption, optimizing the immune system, reducing other inflammatory condition in the body).
SIBO is just one of a number of gastrointestinal conditions that can have an impact on your life. Finding the right balance of therapeutic treatment options, diet and lifestyle changes are the key its eradication.
If this information aligns with symptoms you are experiencing, please schedule a visit with our GI specialist, Dr. Tiffany Althaus, for further evaluation.
1. Dukowicz A, Lacy B, Levine G. Small intestinal bacterial overgrowth: a comprehensive review. Gastroenterol Hepatol (N Y). 2007;3(2):112-122. [PubMed]
2. Siniewicz-Luzeńczyk K, Bik-Gawin A, Zeman K, Bąk-Romaniszyn L. Small intestinal bacterial overgrowth syndrome in children. Prz Gastroenterol. 2015;10(1):28-32. [PubMed]
3. Bouhnik Y, Alain S, Attar A, et al. Bacterial populations contaminating the upper gut in patients with small intestinal bacterial overgrowth syndrome. Am J Gastroenterol. 1999;94(5):1327-1331. [PubMed]
4. Sachdev A, Pimentel M. Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance. Ther Adv Chronic Dis. 2013;4(5):223-231. [PubMed]
5. Lee K, Paik C, Chung W, Yang J, Choi M. Breath methane positivity is more common and higher in patients with objectively proven delayed transit constipation. Eur J Gastroenterol Hepatol. 2013;25(6):726-732. [PubMed]
6. Grace E, Shaw C, Whelan K, Andreyev H. Review article: small intestinal bacterial overgrowth–prevalence, clinical features, current and developing diagnostic tests, and treatment. Aliment Pharmacol Ther. 2013;38(7):674-688. [PubMed]
7. Gabbard S, Lacy B, Levine G, Crowell M. The impact of alcohol consumption and cholecystectomy on small intestinal bacterial overgrowth. Dig Dis Sci. 2014;59(3):638-644. [PubMed]
8. Sabate J, Coupaye M, Ledoux S, et al. Consequences of Small Intestinal Bacterial Overgrowth in Obese Patients Before and After Bariatric Surgery. Obes Surg. 2017;27(3):599-605. [PubMed]
9. Cares K, Al-Ansari N, Macha S, et al. Short article: Risk of small intestinal bacterial overgrowth with chronic use of proton pump inhibitors in children. Eur J Gastroenterol Hepatol. 2017;29(4):396-399. [PubMed]
10/ Brechmann T, Sperlbaum A, Schmiegel W. Levothyroxine therapy and impaired clearance are the strongest contributors to small intestinal bacterial overgrowth: Results of a retrospective cohort study. World J Gastroenterol. 2017;23(5):842-852. [PubMed]
11. 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. [PubMed]
12. Weinstock L, Walters A. Restless legs syndrome is associated with irritable bowel syndrome and small intestinal bacterial overgrowth. Sleep Med. 2011;12(6):610-613. [PubMed]
13. Liang S, Xu L, Zhang D, Wu Z. Effect of probiotics on small intestinal bacterial overgrowth in patients with gastric and colorectal cancer. Turk J Gastroenterol. 2016;27(3):227-232. [PubMed]
14. Yao J, Chang L, Yuan L, Duan Z. Nutrition status and small intestinal bacterial overgrowth in patients with virus-related cirrhosis. Asia Pac J Clin Nutr. 2016;25(2):283-291. [PubMed]
15. Fialho A, Fialho A, Thota P, McCullough A, Shen B. Higher visceral to subcutaneous fat ratio is associated with small intestinal bacterial overgrowth. Nutr Metab Cardiovasc Dis. 2016;26(9):773-777. [PubMed]
16. Fialho A, Fialho A, Thota P, McCullough A, Shen B. Small Intestinal Bacterial Overgrowth Is Associated with Non-Alcoholic Fatty Liver Disease. J Gastrointestin Liver Dis. 2016;25(2):159-165. [PubMed]
17. Egeberg A, Weinstock L, Thyssen E, Gislason G, Thyssen J. Rosacea and gastrointestinal disorders: a population-based cohort study. Br J Dermatol. 2017;176(1):100-106. [PubMed]
18. Enko D, Kriegshäuser G. Functional <sup>13</sup>C-urea and glucose hydrogen/methane breath tests reveal significant association of small intestinal bacterial overgrowth in individuals with active Helicobacter pylori infection. Clin Biochem. 2017;50(1-2):46-49. [PubMed]
19. Niu X, Liu L, Song Z, et al. Prevalence of small intestinal bacterial overgrowth in Chinese patients with Parkinson’s disease. J Neural Transm (Vienna). 2016;123(12):1381-1386. [PubMed]
20 Capurso G, Signoretti M, Archibugi L, Stigliano S, Delle F. Systematic review and meta-analysis: Small intestinal bacterial overgrowth in chronic pancreatitis. United European Gastroenterol J. 2016;4(5):697-705. [PubMed]
21. Zhang Y, Liu G, Duan Y, Han X, Dong H, Geng J. Prevalence of Small Intestinal Bacterial Overgrowth in Multiple Sclerosis: a Case-Control Study from China. J Neuroimmunol. 2016;301:83-87. [PubMed]
22. Cheng X, Zhang L, Xie N, Xu H, Lian Y. Association between small-intestinal bacterial overgrowth and deep vein thrombosis in patients with spinal cord injuries. J Thromb Haemost. 2017;15(2):304-311. [PubMed]
23. Ricci J, Chebli L, Ribeiro T, et al. Small-Intestinal Bacterial Overgrowth is Associated With Concurrent Intestinal Inflammation But Not With Systemic Inflammation in Crohn’s Disease Patients. J Clin Gastroenterol. January 2017.[PubMed]
24. Ponziani F, Pompili M, Di S, Zocco M, Gasbarrini A, Flore R. Subclinical atherosclerosis is linked to small intestinal bacterial overgrowth <i>via</i> vitamin K2-dependent mechanisms. World J Gastroenterol. 2017;23(7):1241-1249.[PubMed]
25. Ghoshal U, Gwee K. Post-infectious IBS, tropical sprue and small intestinal bacterial overgrowth: the missing link. Nat Rev Gastroenterol Hepatol. 2017;14(7):435-441. [PubMed]