Dr. Cash and his colleagues comprehensively reviewed decades of research materials and literature studying Irritable Bowel Syndrome (IBS) and the roles of probiotics and antibiotics.
IBS is a disorder that causes abdominal discomfort or pain. It is associated with a range of symptoms, including intermittent abdominal pain accompanied by diarrhea, constipation, or alternating episodes of both. Other symptoms such as bloating may also be present.
According to Dr. Cash, what causes IBS still remains largely unknown, but a variety of factors play a role in the development of IBS such as stress, gastrointestinal infections, diet, and hormones.
The goal for Dr. Cash’s research review was to evaluate how effective probiotics and antibiotics are on improving IBS symptoms. Probiotics are preparations that consist of bacteria or yeasts, or both that are meant to improve health through their consumption, although the exact mechanisms of how probiotics work in the gastrointestinal tract remain largely conjectural. Because they are “natural product," probiotics are not classified as medicines and are not tightly regulated by the Federal Drug Administration (FDA).
“The idea that probiotics are able to benefit IBS patients still remains very weak, based on our extensive review of the available published data,” Dr. Cash said.
At this point, Dr. Cash does not recommend probiotics for treatment of IBS. When reviewing the data, antibiotics showed more promise than probiotics as therapy for IBS.
Recently, an antibiotic called Rifaximin was approved for IBS and diarrhea. According to Dr. Cash, the data for Rifaximin is quite strong, meaning that it has convincingly demonstrated an ability to improve symptoms of IBS, specifically bloating, abdominal pain and altered stool form, in several large, rigorously designed clinical trials that were presented to the FDA. The exact way that antibiotics work in IBS is unknown, but prevailing theories include the hypothesis that antibiotics may affect the metabolic activity of bacteria in the gastrointestinal (GI) tract and/or that they may also alter the interactions of the GI tract immune system and bacteria. Rifaximin, since it is a non-absorbed antibiotic, “is particulary attractive based on its excellent safety profile and lack of demonstrated bacterial resistance, a real concern with other antibiotics that are systemically absorbed,” said Dr. Cash. He added, “Rifaximin’s safety profile has been shown to be similar to placebo in numerous clinical trials.”
“IBS is very common, and for many years the exact causes for IBS have been unknown. Now we are starting to unravel some of the potential causes of IBS,” Dr. Cash said. “The bacteria in the gastrointestinal tract seems to play a major role in some cases of IBS and we are now starting to develop therapies that address the causes of IBS rather than just the symptoms."
