A relatively new theory points to a condition called small intestine bacterial overgrowth (SIBO) as being a major contributor to IBS. Controversy has surrounded this theory (see Gut Bacteria and IBS). A major part of the SIBO debate has focused on the use and effectiveness of the lactulose breath test (LBT) as a test for IBS. As you can see by the title, a newly published study, “Lactulose Breath Testing Does Not Discriminate Patients With Irritable Bowel Syndrome From Healthy Controls”, sheds some unfavorable light on the use of the LBT to diagnose IBS.

The study compared the LBT results of 224 IBS patients and 40 healthy individuals. A LBT test is considered positive if hydrogen is measured in the breath a short time after drinking a liquid containing the substance lactulose. The SIBO theory holds that it is the fermentation of the lactulose by bacteria in the small intestine that produces this hydrogen. Sadly for the SIBO theory, this study indicated that the LBT was not able to make a diagnostic distinction between the IBS patients and the lucky healthy patients. Only 20 percent of the IBS patients showed a positive LBT. Even worse, 15 percent of the healthy patients showed a positive LBT!

This is discouraging news in terms of the quest to find a clear-cut test that can diagnose IBS. More importantly, this study provides further damaging evidence against the SIBO theory and its recommendation of the use of specific antibiotics as an effective treatment for IBS. All I can say is "UGH!"

_Source:

Bratten, J., Spanier, J. & Jones, M. “Lactulose Breath Testing Does Not Discriminate Patients With Irritable Bowel Syndrome From Healthy Controls” American Journal of Gastroenterology 2008 103:958–963.