What is Small Intestine Bacterial Overgrowth (SIBO)?

SIBO, or small intestine bacterial overgrowth, is a condition where there is an excessive number of bacteria in the small intestine, which affects digestion and absorption. Bacteria are a natural part of our digestive tract, but the highest concentrations of bacteria are usually in the large intestine/colon. Usually the small intestine only houses a small amount of bacteria. SIBO is the cause of 85% of Irritable Bowel Syndrome (IBS). Digestion of nutrients takes place in the small intestine. When a person has SIBO, nutrients are often malabsorbed because the bacteria interferes with the process of digestion and absorption. In fact, the bacteria consume some of the nutrients, which may lead to symptoms of irritable bowel syndrome, including gas, bloating, and pain. The overgrowth of bacteria may also cause intestinal hyperpermeability, also known as leaky gut. Besides gas, bloating, and pain, other symptoms of SIBO are heartburn, constipation and/or diarrhea, osteoporosis, nausea, flatulence, belching, malabsorption, and steatorrhea. There may be deficiencies in vitamin D, K, and B12 as well. Additionally, fatigue, joint/muscle pain, some dermatological conditions, and headaches may be present as well. Many conditions may be responsible for the development of SIBO. These include dysmotility and slow transit time (gastroparesis), inadequate hydrochloric acid, aging, pancreatitis, celiac disease, inflammatory bowel disease, diverticulosis, and inadequate bile acid or pancreatic enzymes. Additionally, the use of certain drugs such as antibiotics, immunosuppressant medications, and proton pump inhibitors may cause SIBO. The lactulose hydrogen breath test is the most common test for SIBO. A baseline breath test is taken followed by ingestion of a solution that contains dextrose or lactulose. The breath is tested every 15 minutes for two hours to determine the levels of hydrogen and methane, which determine a diagnosis of SIBO. If a diagnosis is made, patients are often put on conventional antibiotics or herbal antibiotics. Some herbal antibiotics are oil of oregano, berberine, lemon balm oil, and wormwood oil. Even with antibiotics, SIBO is extremely difficult to treat. The use of probiotics to help symptoms of SIBO is controversial. Various herbs, including glutamine, are used to repair the GI tract after removal of the bacteria in the small intestine. A low FODMAP diet is also recommended for at least two weeks. FODMAPs are short chain carbohydrates which are not properly absorbed in the gut, and they trigger symptoms associated with IBS. They ferment and feed the bacteria, which makes it harder to eliminate the bacteria in the small intestine. FODMAP stands for: fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols. To learn more about the FODMAP diet, visit https://www.monashfodmap.com/i-have-ibs/starting-the-low-fodmap-diet/.