Small Intestinal Bacterial Overgrowth
(SIBO)

Small Intestinal Bacterial Overgrowth Summary
Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least 100,000 bacteria per ml of fluid) are present in the small intestine and the types of bacteria in the small intestine resemble more the bacteria of the colon than the small intestine. There are many conditions associated with small intestinal bacterial overgrowth, to include: diabetes, scleroderma, Crohn's disease, and others. There is a striking similarity between the symptoms of irritable bowel syndrome and SIBO. It has been theorized that SIBO may be responsible for the symptoms of at least some patients with irritable bowel syndrome. Symptoms of SIBO include: excess gas, abdominal bloating, diarrhea, and abdominal pain.
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Small intestinal bacterial overgrowth (SIBO) facts

  • SIBO is a condition in which colonic-type bacteria (resembling bacteria normally found in the colon) proliferate in large numbers in the small intestine.
  • SIBO may be caused by dysfunction of intestinal nerves or muscles, intestinal obstruction, or the presence of a blind loop.
  • The symptoms of SIBO are abdominal bloating or distension, gas, diarrhea, and abdominal pain. In advanced cases, there may be vitamin and mineral deficiencies and weight loss.
  • SIBO is diagnosed by culturing intestinal fluid or with hydrogen breath testing.
  • SIBO may be the cause of symptoms in at least some patients with irritable bowel syndrome.
  • SIBO is treated with antibiotics, probiotics, or a combination of both.

Small intestinal bacterial overgrowth (SIBO) introduction

Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (usually defined as at least 100,000 bacteria per ml of fluid) are present in the small intestine and the types of bacteria in the small intestine resemble more the bacteria of the colon than the small intestine. There are many conditions associated with SIBO including diabetes, scleroderma, Crohn's disease, and others. There is a striking similarity between the symptoms of irritable bowel syndrome and SIBO. It has been theorized that SIBO may be responsible for the symptoms of at least some patients diagnosed with irritable bowel syndrome. Symptoms of SIBO include: excess gas, abdominal bloating, diarrhea, and abdominal pain.

What is small intestinal bacterial overgrowth (SIBO)?

The small bowel, also known as the small intestine, is the part of the gastrointestinal tract that connects the stomach with the colon. The main purpose of the small intestine is to digest and absorb food into the body. The small intestine is approximately 21 feet in length and begins at the duodenum (into which food from the stomach empties), followed by the jejunum, and then the ileum (which empties the food that has not been digested and absorbed in the small intestine into the large intestine or colon).

The entire gastrointestinal tract, including the small intestine, normally contains bacteria. The number of bacteria is greatest in the colon (usually defined as at least 1,000,000,000 bacteria per milliliter (ml) of fluid) and much lower in the small intestine (less than 10,000 bacteria per ml of fluid). Moreover, the types of bacteria within the small intestine are different than the types of bacteria within the colon. Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (usually defined as at least 100,000 bacteria per ml of fluid) are present in the small intestine and the types of bacteria in the small intestine resemble more the bacteria of the colon than the small intestine. It has been suggested, however, that SIBO and its symptoms may occur with smaller numbers of bacteria, for example, 10,000 per ml of fluid.

SIBO also is known as small bowel bacterial overgrowth.

Medically Reviewed by a Doctor on 3/10/2014

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