Health Problems That May Raise Your Risk for SIBO

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Small intestinal bacterial overgrowth (SIBO) is a health condition that was once thought to be a rare problem. More recently, researchers have been focusing on the connection between SIBO and a wide variety of health disorders. In this overview, you will learn which conditions have been investigated that may raise your risk for developing SIBO. You can then use this information to open up a discussion with your doctor as to whether or not it makes sense for you to be tested and perhaps subsequently treated for SIBO.

What Is SIBO?

SIBO is diagnosed when there is an increased number of bacteria, and/or changes in the types of bacteria, present in your small intestine. Typically the presence of bacteria in the small intestine is quite limited, as opposed to the large amounts of bacteria housed in the large intestine. These changes in the amount and makeup of bacteria can directly cause symptoms, for example, excessive intestinal gas, or cause symptoms indirectly by preventing the nutrients that you eat from being absorbed properly into your body.

SIBO is thought to occur due to a breakdown in the body's own defense systems that typically keep the bacterial count in the small intestine at a low level. There are a variety of things that can cause this breakdown, for example, changes in the acid level of the stomach, a decreased amount of enzymes released by the pancreas, or structural and anatomical changes.

SIBO remains a poorly understood and somewhat controversial diagnosis. This is due in part that there are problems with the validity of current testing methods. In addition, in research reports, healthy individuals have also been found to have higher levels of bacteria in the small intestine without any resulting symptomatology. That being said, SIBO is thought to be quite under-diagnosed and therefore missed as a contributing factor to symptoms that people may be experiencing.


The symptoms of SIBO can vary widely. In some cases the symptoms may be minimal or attributed to other health problems. However, the more typical symptoms include:

Associated Conditions

SIBO does not necessarily stand alone. The conditions for the development of SIBO may be the result of a disease or SIBO itself can create an ongoing health problem. In some extreme cases, there is a "chicken and egg" situation between SIBO and another disease, in which each disease contributes to the maintenance of the other. Here are some health conditions that have been a primary focus for SIBO researchers:

Gastroesophageal reflux disease (GERD): Research has indicated that people who have GERD are at higher risk for the development of SIBO. This is not thought to be due to the GERD itself, but rather the decrease in stomach acid as the result of long-term use of proton pump inhibitors (PPIs).

Irritable bowel syndrome (IBS): IBS and SIBO have quite a deal of overlap in terms of symptoms, however the relationship between the two remains unclear. It is believed that a certain sub-set of people who are diagnosed with IBS actually have SIBO and thus it is the SIBO that is behind unpleasant intestinal symptoms. Other researchers believe that it is the dysfunction of IBS that sets the stage for the development of SIBO.

Celiac disease: Researchers are finding that celiac disease may increase a person's risk for developing SIBO. It is theorized that either chronic inflammation on the lining of the small intestine, or slower motility within the small intestine, or both, sets the stage for bacterial overgrowth. If a person who has celiac disease has persistent abdominal symptoms in spite of following a strict gluten-free diet, it is recommended that they be evaluated for the presence of SIBO and then treated accordingly.

Crohn’s disease: Researchers estimate that as many as 25% of the people who have Crohn's disease may also have SIBO, with a higher risk seen in those who had surgery for the inflammatory bowel disease. Ruling out SIBO may be important as SIBO could be misdiagnosed as an acute flare-up of the Crohn's disease itself.

Diabetes: Researchers have found that people who have long-term diabetes are at risk for also having SIBO. It is thought that having diabetes can damage the workings of the digestive system and thus set up conditions in which SIBO develops. If you have diabetes and also experience gastrointestinal symptoms, it might be a good idea to talk to your doctor about being tested for SIBO, particularly since the combination of diabetes and SIBO may lead to malabsorption of essential nutrients.

Other Health Conditions Being Investigated for an Association with SIBO

As you will see by the following list, there are a wide range of health problems that researchers have been investigating regarding a possible link with SIBO:

Link to Aging

No discussion of the risk factors for SIBO is complete without noting that aging itself raises the risk for SIBO. This is thought to be due, in part, to a general slowing down of the movement of the digestive system. This risk is heightened if a person has used PPIs for a long time or has had previous gastrointestinal surgery. In older people, SIBO can result in a malabsorbtion of nutrients and subsequent weight loss.


If you have any of the health conditions listed above and you struggle with ongoing gastrointestinal symptoms, it would be worth your while to have a conversation with your doctor about being evaluated for the presence of SIBO.

There are three main ways to test for SIBO—through the use of hydrogen breath testing, through testing samples of the fluid in the small intestine taken during an endoscopy, or through a trial of specific antiobiotics. Each method has its benefits and its limitations, although the direct sampling method through endoscopy is considered to be the most reliable.

The good news is that in most of the research studies that have evaluated SIBO in groups of people who have specific health problems, treating the SIBO was effective in reducing its symptoms.


As of now, the primary treatment for SIBO is the use of specific antibiotics that are not absorbed at the level of the stomach and therefore act directly on the bacteria within the small intestine. It may take multiple two-week courses of the medication before the SIBO is eradicated. Once you have finished taking the medication, your doctor ma recommend that you follow the low-FODMAP diet in order to prevent a recurrence of SIBO.

Some scientists are investigating the effectiveness of the use of the elemental diet in addressing SIBO. This involves being on a liquid diet, drinking a specific nutritional formulation. However, as this is a difficult diet to maintain, even for the recommended two week duration, this would be a rarely used treatment option.

A Word From Verywell

In spite of a recent surge in research, SIBO remains a mysterious and nebulous diagnosis. It is important to recognize that at this point, our understand of its importance, testing, and treatment are very far from complete. 

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