Small Intestine Bacterial Overgrowth – SIBO: Putting Things Back in Order

By Karen Wheeler, APRN

The human body is an amazing thing. We actually have about 100 trillion of cells in our body but only one in 10 of those cells is actually a human cell. The rest are bacteria, virus and other microbes. It turns out that the human body needs these other microorganisms to work correctly. This is especially true when it comes to the gastrointestinal tract where we depend on “good” bacteria to extract vitamins and other nutrients as well as keeping the “bad” bacteria and other microorganisms, like yeast, under control.

The small intestine is supposed to have much fewer bacteria living in it than the large intestine (aka colon). But sometimes things go awry and the bacteria from the colon can shift into the small intestine where they can cause problems. Risk factors for developing SIBO include the use of medications or conditions that would decrease stomach acid, motility disorders like those that occur with neurological, muscular disorders or diabetes, anatomical abnormalities like diverticula or after surgeries on the small bowel or fistulas that form with inflammatory bowel diseases and problems with a person’s immune system may contribute to bacterial overgrowth.

Symptoms of SIBO include gas, abdominal bloating, distention and pain. Also, it can cause either diarrhea or constipation which makes some healthcare providers think that irritable bowel syndrome is caused by SIBO. Some SIBO patients report chronic fatigue, generalized body aches and weight loss. Some with severe bacterial overgrowth can have low levels of vitamins and minerals, because absorption of these is affected. Symptoms are quite variable in intensity which contributes to making a clear diagnosis take months or years.

Testing for overgrowth of small bowel bacteria is done best by a hydrogen breath test. For this test to give the most accurate results, the patient restricts their intake of any foods or drinks that would feed the gut bacteria for 1–2 days. The test is done in a fasting state when the patient has not had anything to eat or drink for 12 hours. A baseline breath sample is obtained for comparison. The patient then drinks a set amount of lactulose, or glucose. Next, the patient breathes into a collection chamber every 15 minutes for 3 more hours to monitor for generation of Hydrogen and Methane gases.

Lactulose is a sugar that that human body cannot digest. It is digested by bacteria that normally live inside the colon and produce methane gas as a byproduct. In a normal patient, there is only one peak of the gas generated from the digestion of lactulose, indicating the time that the sample enters the large intestine and bacteria located there start digesting it. In patients who have SIBO, there is usually more than one peak of the gas, indicating that some digestion is being done by bacteria prior to the time that the sample could enter the large intestine. Glucose has also been used at times to do this test. Glucose is easily digested and should be gone before reaching the colon, so normally there is no gas in the breath of the patient who ingests glucose. Detecting gas in the patient’s sample after drinking glucose would indicate that there are bacteria in the small intestine reacting to it. In some cases, patients will need to have endoscopy to look directly at the gut lining and biopsies taken of the stomach and duodenum to verify this diagnosis. Some providers choose to treat the patient with symptoms of SIBO based on their symptoms without any testing.

Treatment options include conventional antibiotics such as Rifaximin, Neomycin or Metronidazole, natural antibiotics such as Berberine, Oregano, garlic or cinnamon, and diet changes. Since bacteria in the gut live on the carbohydrates that a person ingests, the diet changes are based on the restriction of these for various lengths of time. An elemental diet consists of replacing meals with powdered nutrients, including basic amino acids, fatty acids, and glucose, plus vitamins and minerals. There are many brands of these formulas available to purchase, but there are also recipes for patients to make their own. The patient would stay on this diet for a minimum of 2 weeks to starve the bacteria in the small intestine. A few of the diets designed to treat SIBO include Specific Carbohydrate Diet (SCD), the Gut and Psychology Syndrome Diet (Gaps diet), and Low FODMAP (LFD) diet. A combination of SCD and LFD has also been used. Other diets are also available to treat SIBO.

The SCD diet allows meat, fish and poultry, some eggs and beans, lactose-free dairy, non-starchy vegetables, ripe fruit, nuts and seeds, honey and saccharine. Grains, starchy vegetables, lactose, and any other sweeteners are not allowed. This method starts with an introduction diet and progresses as the intestines heal. The book explaining this diet includes recipes. Websites are available for more information. It has a 75–85% success rate if it is followed strictly.

The Gaps diet is basically the SCD diet with a few modifications allowing less beans, no baking soda or store-bought juice. The protein casein is introduced more slowly and altered vegetables are emphasized in place of yogurt. Several books and websites are available for support and information when following this diet.

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. This diet allows grains, fiber, sugar and other fermentable carbohydrates and has had excellent success rates in treating IBS and other GI conditions. It may need to be adapted for patients with SIBO because of the carbohydrates allowed. Resources can be found online and in books.

Most often, people have to be on these diet changes for more than a year, and some for a lifetime. The best news is that people with SIBO often feel better within a few weeks of making diet changes and other treatments. Children often respond faster than adults. It’s important to realize that a combination of these treatment options may be needed. More than one round of conventional or natural antibiotics may be needed to achieve results.

This is another condition where prevention is the key. Being mindful of what a person eats and drinks will contribute to overall good health. Follow a diet that is low in sugar and has proper portion sizes. Take steps for normal digestion by protecting the hydrochloric acid in the stomach by avoiding medications that suppress the acid, or by taking supplemental HCL, apple cider vinegar or bitter herbs. Digestive enzyme supplements may also help. Taking probiotics are important to maintain normal gut flora and help with small bowel motility.

Make certain that you purchase all supplements from a reputable supplier as these are not monitored by the FDA and have been found to not contain what the person thinks they’re buying. Riordan Clinic Nutrient Store can provide you with many of the supplements mentioned in this article. Our supplements are tested for quality assurance by an independent lab. The providers here at Riordan Clinic are all capable of helping you with any digestive or elimination issues that you may be experiencing, as well as any other conditions that may need attention. We look forward to seeing you and helping you achieve and maintain excellent health.

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