Irritable Bowel Syndrome (IBS) may be caused by bacteria overgrowth

Antibiotics appear to be effective in reducing 75% of IBS symptoms as they destroy bacteria in the small intestine. More studies will be necessary to determine if this could be a possible solution to IBS.

• The enigmatic-but-common condition known as irritable bowel syndrome, or IBS, is caused by an overgrowth of bacteria in the small intestine, a USC researcher has proposed in the Journal of the American Medical Association.
• Researchers have suggested numerous theories to explain IBS, which affects as many as 36 million Americans.
• But according to gastrointestinal motility specialist Henry C. Lin, associate professor of medicine in the Keck School of Medicine of USC, the idea of a bacterial origin of IBS represents a major change in thinking.
• "IBS has long been a frustrating diagnosis for both patients and their physicians," Lin said.
• "The bacterial hypothesis of IBS offers new hope for suffering patients by providing a new framework for understanding the symptoms of this disorder, pointing to new strategies for treatment."
• Physicians frequently diagnose a patient with IBS when ongoing symptoms - including diarrhea, constipation, bloating, gas and abdominal pain - are not explained by medical tests such as gastrointestinal endoscopies.
• For more than a dozen years, Lin has searched for a common thread to account for the symptoms in IBS.
• There are plenty of organisms in the gut, where bacteria may number 100 trillion.
• In this test, the patient ingests a syrup containing the sugar lactulose.
• Over the next three hours, the gaseous products of bacterial fermentation of this sugar may be measured in the exhaled breath.
• In a 2003 paper authored by Lin and his research partner Mark Pimentel of Cedars-Sinai Medical Center, 84 percent of IBS patients were found to have abnormal breath test results suggesting small intestinal bacterial overgrowth.
• "The immune response to bacterial antigens may then explain the flu-like symptoms that can greatly diminish the quality of life such as chronic fatigue and pain," Lin said.