Irritable Bowel Syndrome (IBS)

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Irritable bowel syndrome (IBS) definition

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by the presence of a cluster of symptoms that includes abdominal pain, altered bowel habits, increased gas, bloating (distention), cramping, and food intolerance.

Irritable bowel syndrome is a "functional" disorder. This term refers to the changes in the functioning of the digestive system that results in the collection of symptoms referred to as IBS. Meaning that it is a problem with the movement (motility) rather than any damage to the tissues of the digestive system.

In the past, irritable bowel syndrome was also called spastic colon or bowel, functional bowel disease, mucous colitis, or nervous colon. IBS is not the same as colitis, which is a group of separate conditions also referred to as inflammatory bowel disease (IBD).

What causes irritable bowel syndrome (IBS)?

The exact cause of irritable bowel syndrome (IBS) is unknown. It is believed to be due to a number of factors including alteration in the gastrointestinal (GI) tract motility, abnormal nervous system signals, increased sensitivity to pain, and food intolerances. Some factors believed to cause IBS include:

  • Abnormal movements of the colon and small intestines (too fast or slow, or too strong)
  • Hypersensitivity to pain from a full bowel or gas
  • Food sensitivities, possibly caused by poor absorption of sugars or acids in food
  • Gastroenteritis, a viral or bacterial infection of the stomach and intestines, may trigger IBS symptoms
  • Psychological conditions such as anxiety or depression are observed in many people with IBS, though they have not been found to be a direct cause of IBS.
  • Reproductive hormones or neurotransmitters may be off-balance in people with IBS
  • Small intestinal bacterial overgrowth (SIBO)
  • Genetics is thought to be a possible cause of IBS, but so far this link has not been proven.
Medically Reviewed by a Doctor on 2/28/2014

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Irritable Bowel Syndrome (IBS) - Diet Question: What dietary changes have you made that have improved your case of IBS?
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IBS (Irritable Bowel Syndrome) and Diet

What Foods Trigger Symptoms of Irritable Bowel Syndrome (IBS)?

For many people, careful eating reduces IBS symptoms. Before changing your diet, keep a journal noting the foods that seem to cause distress. Then discuss your findings with your doctor. You may want to consult a registered dietitian who can help you make changes to your diet.

Examples of diet and IBS triggers include:

  • Dairy products
  • Low fiber diet
  • Dehydration
  • Eating large meals
  • Eating low carbohydrate meals
  • Eating high fat content meals

REFERENCE: NIH