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SIBO: All You Need to Know About Small Intestinal Bacterial Overgrowth

Written by Dr. Group, DC Founder
Herbal supplements and probiotics are natural approches to SIBO

If you frequently experience gas, bloating, abdominal pain, nausea, diarrhea or constipation, you might brush off your symptoms or blame it on something you ate. But if those symptoms linger, you might consider whether you have a more serious health condition.

When dealing with gastrointestinal symptoms, people often consider irritable bowel syndrome (IBS), leaky gut syndrome, or candida yeast overgrowth. But, researchers have uncovered another sneaky condition that can cause gastrointestinal (GI) distress: small intestinal bacterial overgrowth or SIBO. Experts say that the number of people diagnosed with SIBO is on the rise. Since SIBO is not yet fully understood, it often goes undiagnosed or misdiagnosed.[1, 2]

What is SIBO, and what are the symptoms of SIBO? Are there natural therapies that help it? Here, we’ll provide answers with our natural health guide to SIBO.

SIBO: A Quick Overview

Here are some quick facts about small intestinal bacterial overgrowth (SIBO).
  • Bacteria are needed for digestion, but when things get out of balance, it can cause overgrowth.
  • SIBO is an increase in the number or an alteration in the type of bacteria in the upper GI tract.
  • Common symptoms include gas, bloating, and abdominal swelling.
  • SIBO is often misdiagnosed as other conditions.
  • A breath test is the most common way to tell if you have SIBO.
  • Diet, supplements, and probiotics are natural ways to help alleviate symptoms.

How a Healthy Gut Works

Before we can fully understand SIBO, it’s important to understand the gut environment, which contains much of your body’s microbiome. Your microbiome is a community of microorganisms. The idea of bacteria living in you might not sound appealing, but your body has a symbiotic relationship with the many species of probiotic bacteria that strengthen your immune system and keep you healthy.

When things run smoothly, your body digests food as it passes through the gastrointestinal (GI) or digestive tract. As food makes its way from the mouth into the esophagus and on into the stomach, muscles, nerves, and neurotransmitters like serotonin help move it through the various stages of digestion.

As the food mass, called a bolus, moves through the GI tract, digestive juices and digestive enzymes break down macronutrients so they can be absorbed into the bloodstream. Probiotic bacteria and digestive enzymes in the digestive tract further aid digestion. Although gut flora helps our bodies absorb vitamins and minerals, produce beneficial digestive enzymes, and fight off harmful bacteria, sometimes things get out of balance, leading to an overgrowth of bacteria in the small intestine, or SIBO.

What Is SIBO?

SIBO, or small intestinal bacterial overgrowth, is an increase in the number or an alteration in the type of bacteria in the upper gastrointestinal tract. Although the large intestine normally has many bacteria, the small intestine generally does not have large colonies of bacteria. A digestion issue can cause an imbalance and lead to SIBO. Having more than 100,000 colony-forming units (CFU) of bacteria per mL in a small intestinal aspirate, a collection of digestive material, is considered diagnostic of SIBO.[2]

Under healthy conditions, several processes keep bacteria levels in check in the small intestine: gastric acid secretions, the normal muscular movement of food through the GI tract, the bacteria-killing properties of bile produced by the liver and pancreas, and an intact ileocaecal valve (which separates the small and large intestine).[2]

In some people, SIBO is asymptomatic, and in other cases, the symptoms are present, and caused by conditions that caused the bacterial overgrowth — a faulty ileocaecal valve for example. Because SIBO often co-occurs with other conditions, it may not get diagnosed unless a doctor or healthcare provider runs tests.

Symptoms of SIBO

The symptoms of SIBO may include some or all of the following:[2]

Since SIBO can cause nutritional deficiencies and malabsorption issues, particularly with protein and fats, the condition can look much like IBS.

What Conditions Does SIBO Co-Occur With?

Because SIBO is often misdiagnosed as other conditions, medical professionals are still unsure how many people have SIBO. One study suggested that between 2.5 and 22 percent of people are affected. Some experts believe SIBO occurs more often in women, although others believe it occurs equally in men and women.[3, 4]

SIBO is more common in people with other conditions. Hypochloridia — low stomach acid — is a common, co-occurring condition. Among people with no symptoms, 17 percent of morbidly obese individuals had SIBO compared with 2.5 percent of non-obese individuals.[2] SIBO frequency increases with age. SIBO was present in 90 percent of elderly people aged 70 to 94, and particularly those who could not absorb lactose.

SIBO may also co-occur with other GI conditions. Thirty to 85 percent of people with IBS and 50 percent of people with celiac disease but whose condition was not responding to a gluten-free diet may also have SIBO.[2] People with scleroderma, a connective tissue condition, or who have had radiotherapy, may have increased chance of SIBO. SIBO is also more common among alcoholics than in the general population. Also, up to 50 percent of people with cirrhosis of the liver may have SIBO.

People with Type-2 diabetes have an increased risk of getting SIBO because diabetes affects intestinal motility, which is the effectiveness with which food moves through the digestive tract.[1]

Some vitamin deficiencies co-occur with SIBO, including B12, iron, and fat-soluble vitamins (A, D, E, K). Experts believe SIBO causes the B-12 deficiency, rather than the other way around.[1] People with gastritis and SIBO absorb less B12, likely because the bacteria absorb the B12, leaving less for human absorption.

What Causes SIBO?

Experts believe that several factors contribute to a small intestinal bacterial overgrowth. SIBO is not just caused by so-called bad bacteria. Good bacteria can also get out of balance in the gut and grow beyond normal levels.

Keeping bacteria in check in the small intestine depends on the healthy functioning of various digestive processes, including stomach gastric acid secretions, the normal muscular movement of food through the GI tract, the bacteria-killing properties of bile produced by the liver and pancreas, and an intact ileocecal valve (which separates the small and large intestine). Anything that affects these processes can disrupt the gut and lead to SIBO.

Conditions that affect the GI tract, such as diabetes, immunodeficiency and autoimmune conditions, celiac disease, or Crohn’s disease, may trigger a bacterial overgrowth in the small intestine.[2]

Physical damage in the GI tract, caused by surgery or a byproduct of other conditions, can lead to SIBO. A damaged ileocaecal valve can cause bacteria from the large intestine to go back into the small intestine. Other factors that can cause bacteria to enter the small intestine from the colon include intestinal obstruction, diverticulitis, a loss of the normal muscular motility of the GI tract, or when stool gets backed up in the large intestine (colon).[2]

There appears to be a link between IBS and SIBO, and the two conditions have overlapping symptoms. However, scientists still do not agree whether IBS causes SIBO, or SIBO causes IBS. Some believe that the IBS disrupts the normal gut motility, leading to bacterial overgrowth, while others believe that the SIBO causes the symptoms of IBS. A third group of experts believes SIBO and IBS are different conditions and should be treated separately.[2]

How Is SIBO Diagnosed?

Since SIBO often mimics other conditions that affect gut health, it may not be the first condition your doctor thinks to test for. You can bring it up with your healthcare provider and ask for specific tests.

Testing for SIBO

There are two main ways to diagnose SIBO: a breath test and a bacterial culture, and there is scientific disagreement over which is best. A breath test is the simplest, least invasive, and most commonly used test for SIBO. There are multiple types of breath tests used, but the two most common are the glucose hydrogen and the lactulose test. These tests measure the gases produced by bacteria in the intestines from your breath.

If you are going to take a breath test for SIBO here is what to expect. You will be asked to fast overnight and avoid eating unfermented carbohydrates such as whole grain bread or pasta. Smokers are advised not to smoke for a couple of hours before the test. During the test day, you will first drink water infused with either glucose or lactulose. Next, a technician will collect a breath sample from you every 15 to 30 minutes over a total of 3 to 4 hours. The healthcare provider can determine whether you have SIBO by measuring the level of hydrogen gas produced in the breath samples, which is produced by bacteria.

The lactulose breath test is more often found to be positive in individuals with GI symptoms than the glucose breath test.[4]

Both tests may miss SIBO if a species that does not metabolize carbohydrates to hydrogen gas (as most bacteria do) is responsible. You may be mistakenly diagnosed with SIBO if you have hydrogen-producing bacteria present in the mouth.

The other SIBO test involves a bacterial culture taken directly from the small intestine. In this test, an endoscope will be inserted through your mouth and down into the upper part of the small intestine. The doctor will take a sample of bacteria from inside your body, and then the endoscope is removed. Next, that sample is cultured in a Petri dish to determine the numbers and species of bacteria present and whether there is an overgrowth. Although this test directly measures the bacteria present, it has other drawbacks. Concerns with the culture test include that it is more invasive, the sample may get contaminated with other bacteria on the esophagus or mouth, and the endoscope can only reach the upper small intestine although the bacterial overgrowth may be further down the GI tract.

How Is SIBO Treated?

The first-line approach by most traditional doctors for SIBO is antibiotics. Augmentin and Xifaxan are two of the most commonly prescribed antibiotics, usually for a course of one to two weeks. However, some people will experience a relapse of symptoms after the course of antibiotics is finished, and have to repeat the treatment. Hence, antibiotics may not be the best solution for SIBO.

Antibiotics have side effects that range from mild to severe. Yeast infections are a common side effect of taking antibiotics; since antibiotics indiscriminately kill bacteria and other microbes, they tend to kill off the good bacteria that keep Candida yeast in check under normal conditions. On a bigger scale, the regular use of antibiotics by people — as well as in food animals — is resulting in many antibiotic-resistant strains of bacteria, which is a major health concern worldwide.[5]

There are natural approaches to SIBO and other gastrointestinal issues that can work together with traditional medicine or independently to try to optimize health.

Natural Approaches to SIBO

If you want to address SIBO with complementary approaches to conventional treatment, there are some dietary changes along with natural supplements, probiotics, and lifestyle habits that can address your symptoms.

A SIBO Diet May Help Reduce Symptoms

Altering your diet is an easy and natural way to start alleviating the symptoms that go along with SIBO. Naturopathic doctors have developed a couple of different eating plans that may reduce the symptoms of SIBO or kick it to the curb.

The first option is called the specific carbohydrate diet (SCD) in which you eliminate all complex carbohydrates, which includes grains, beans, and other legumes, complex sugars and starches.[6] The creator of the diet, Sidney V. Haas, treated a patient’s child who was suffering from major gastrointestinal issues, and the nutritional approach healed the child. The mother, Elaine Gottschall, went on to author a book called Breaking the Vicious Cycle: Intestinal Health through Diet. The accompanying website has a list of allowed and disallowed foods.[6]

The second SIBO diet option recommended is called the gut and psychology syndrome diet (GAPS) which eliminates all beans, grains, starchy vegetables, lactose and sweeteners except honey.[7] The GAPS diet was modified from the SCD. It involves three parts: diet, detoxification, and supplementation with probiotics, essential fatty acids, vitamin A, and digestive enzymes.

A third option is the low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet. FODMAPs are carbohydrates and sugar alcohols that the body cannot digest well. By avoiding them, the bacteria get starved out, and the body can start to heal.

Other helpful strategies include following a gluten-free diet. Gluten may cause intestinal hyperpermeability, which leads to leaky gut syndrome. Exercise is a good lifestyle habit that improves blood circulation and hence digestion.

Herbal Remedies & Supplements for SIBO

Herbal therapy may be effective for SIBO. Nearly half of people diagnosed with SIBO who used a natural, herbal therapy were negative for SIBO afterward, compared to 34 percent negative after using antibiotics.[8] The herbal remedies used in this study contained several ingredients, including oregano oil, Pau D’arco, lemon balm leaf, and red thyme oil.

Supplements that contain herbs such as oil of oregano, thyme, berberine extracts, and wormwood are also ideal for managing SIBO symptoms. Turmeric, which has soothing qualities may ease SIBO symptoms and support gut health. Some research suggests that zinc-carnosine supplements can help with gut issues.[9]

If your SIBO is associated with a vitamin deficiency, you may benefit from supplements. Vitamin B12 deficiency is a common issue experienced by people with SIBO. Additionally, deficiencies may develop in iron and vitamins A, E, K, and D.

Probiotics for SIBO

A supplement containing both probiotics and prebiotics are beneficial for SIBO because they support gut health, keep harmful organisms in check, and soothe irritation and redness. Consuming probiotic-rich foods or probiotic supplements can also help restore gut health.

Probiotics can relieve abdominal discomfort and are an effective approach for SIBO.[10] What’s more, probiotics have been shown to be 30 percent more effective than antibiotics at remedying SIBO.[11]

I recommend a multi-strain, high-quality probiotic like Global Healing's Ultimate Probiotic. This advanced formula contains 25 unique strains and 75 billion CFUs that support digestion and intestinal function.

Avoiding SIBO

If you can avoid SIBO altogether, you’ll be better off. Eat a nutritious, plant-based diet, and avoid diets high in sugar and processed foods. Maintain your health with fitness, meditation, and periodic fasting.

To promote a balanced gut, rid your body of toxins, and boost your energy, perform a colon cleanse. A cleanse, along with an accompanying colon cleansing diet, is one of the most proactive measures you can take. Many people consider a regular colon cleanse to be an essential part of gut health maintenance. One thing is clear — a healthy body begins with a healthy gut!

What’s Your Story?

References (11)
  1. Dukowicz A, et al. "Small Intestinal Bacterial Overgrowth." Gastroenterology & Hepatology. 2007; 3(2): 112–122.
  2. Bures J, et al. "Small intestinal bacterial overgrowth syndrome." World Journal of Gastroenterology. 2010; 16(24): 2978–2990.
  3. Reddymasu S, et al. "Small intestinal bacterial overgrowth in irritable bowel syndrome: are there any predictors?" BMC Gastroenterology. 2010; 10: 23.
  4. Mattsson J, et al. "Outcome of breath tests in adult patients with suspected small intestinal bacterial overgrowth." Gastroenterology and Hepatology From Bed to Bench. 2017; 10(3): 168–172.
  5. Zaman SB, et al. "A Review on Antibiotic Resistance: Alarm Bells are Ringing." Cureus. 2017; 9(6):e1403.
  6. "Intestinal Health Through the Specific Carbohydrate Diet." breakingtheviciouscycle.info. Accessed 16 Apr. 2018.
  7. "Welcome to the GAPS Diet." Accessed 16 Apr. 2018.
  8. Chedid V, et al. "Herbal Therapy Is Equivalent to Rifaximin for the Treatment of Small Intestinal Bacterial Overgrowth." Global Advances in Health and Medicine. 2014; 3(3): 16–24.
  9. Mahmood A, et al. "Zinc carnosine, a health food supplement that stabilises small bowel integrity and stimulates gut repair processes." Gut. 2007;56(2),168–175.
  10. Zhong C, et al. "Probiotics for Preventing and Treating Small Intestinal Bacterial Overgrowth: A Meta-Analysis and Systematic Review of Current Evidence." Journal of Clinical Gastroenterology. 2017;51(4):300-311.
  11. Soifer LO, et al "[Comparative clinical efficacy of a probiotic vs. an antibiotic in the treatment of patients with intestinal bacterial overgrowth and chronic abdominal functional distension: a pilot study]." Acta Gastroenterol Latinoam. 2010;40(4):323-7.

†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.


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