SIBO and IBS cause similar symptoms. Doctors can differentiate SIBO from IBS with breath tests or by taking a sample of fluid from your small intestines.
Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) condition that can cause symptoms such as
Small intestinal bacterial overgrowth (SIBO) occurs when there are too many bacteria and other microorganisms in your small intestines. Its symptoms widely overlap with IBS and
SIBO is commonly misdiagnosed as IBS, and the two conditions have been reported as overlapping in as many as
Read on to learn more about the difference between SIBO and IBS.
IBS is a functional GI condition, meaning that it’s caused by problems with your brain-gut interaction. It’s thought to affect about
- stressful events early in life
- bacterial infections
- food intolerances and sensitivities
- anxiety and depression
IBS is further broken down into the following categories depending on which symptoms are predominant:
- IBS with predominant constipation (IBS-C)
- IBS with predominant diarrhea (IBS-D)
- IBS with mixed bowel habits (IBS-M)
SIBO is an overgrowth of bacteria and other microorganisms in your small intestines. Excess bacteria can cause similar symptoms to IBS such as abdominal pain and diarrhea.
The exact cause of SIBO is still poorly understood. The upper part of your small intestines rarely contains more than
SIBO has been associated with conditions that reduce stomach acid production or disturbances in
- connective tissue disorders
- chronic opioid use
- small bowel adhesions (which are lumps of scar tissue in your bowel)
- diabetic enteropathy
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IBS and SIBO symptoms are nonspecific and overlap. Many people are thought to have both conditions. Symptoms that occur in more than
- abdominal bloating
- excess gas
- a feeling of abdominal fullness
- abdominal cramping
- altered bowel habits, which can be diarrhea or constipation
Some people also develop:
IBS and SIBO cause overlapping symptoms.
SIBO develops in your small intestines, which is responsible for fat absorption. People with severe SIBO may develop a deficiency of fat-soluble
and other nutrients such as:
SIBO symptoms are nonspecific, which makes it very easy to misdiagnose with IBS and other GI conditions.
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Doctors primarily diagnose IBS by reviewing your symptoms and performing a physical exam. Doctors widely follow the Rome IV criteria when making a diagnosis. According to the Rome IV criteria, a diagnosis can be made if you have recurrent abdominal pain for an average of 1 day or more per week in the last 3 months associated with:
- pain when having a bowel movement
- changes in your bowel movement frequency
- changes in the appearance of your stool
Your doctor may order additional tests such as
Breath tests are noninvasive, cheap, and fast. Another test doctors can use to help diagnose SIBO is a jejunal aspirate culture.
During this test, doctors take a small sample of the fluid from your small intestines using a long, thin tube. This procedure is called an esophagogastroduodenoscopy (or EGD test) More than
SIBO may lead to fat malabsorption that causes your poop to float and appear oily, smelly, or watery.
They may cause other changes such as:
- loose, soft, and watery stools
- mucus in your stool
- thin and pencil-like stools
- hard and lumpy stools
It’s important to seek immediate medical attention if your stool is bright red or tar-colored.
IBS can be treated with:
- dietary changes like:
- following a FODMAP diet
- exercising regularly
- reducing stress
- improving sleep quality
- medications to treat diarrhea
- medications or fiber supplements to treat constipation
- other medications such as:
Antibiotics are the main treatment for SIBO. But, about
Doctors sometimes recommend a liquid diet called the elemental diet if you don’t respond to antibiotics or if you can’t tolerate antibiotics.
SIBO and IBS are common GI conditions that cause similar symptoms such as diarrhea, abdominal pain, or bloating. Many people who have IBS also have SIBO.
It isn’t usually possible to tell SIBO and IBS apart based on your symptoms alone. Doctors can perform tests such as a carbohydrate breath test or a jejunal aspirate culture to help differentiate them.