Study evaluates safety, efficacy and tolerability of probiotics for irritable bowel syndrome

A new analysis of randomized controlled trials evaluating probiotics in the treatment of irritable bowel syndrome (IBS) has found that Bifantis, Bifidobacterium infantis 35624, the sole ingredient in Align (manufactured by Procter & Gamble), is the only probiotic currently able to demonstrate significant improvement in IBS symptoms based upon a properly designed research study.

Researchers at the University of Michigan conducted the review to evaluate the safety, efficacy and tolerability of probiotics for IBS in randomized controlled trials and found that, with the exception of the Bifidobacterium infantis 35624 studies, most were not designed in a way that made the data possible to validate. The review data were presented this week at the annual American College of Gastroenterology (ACG) conference taking place in Philadelphia, PA.

“There is growing interest in medical and patient communities about the use of probiotics in IBS and lots of data has been published about this topic, but it's helpful to know the quality of that data before making a treatment decision,” said Darren Brenner, MD, lead investigator on this project. “Our analysis showed that only this particular strain of probiotic, Bifidobacterium infantis 35624, has valid data for successfully treating IBS symptoms. At this point, we just don't have enough valid data to determine if other probiotics are effective for IBS.” 

The goal of this systematic review of randomized controlled trials was to evaluate the efficacy, safety and tolerability of probiotics in the treatment of IBS. Criteria for the study included randomized controlled trials testing adults with IBS symptoms using single or combination probiotics versus placebo for IBS symptoms and frequency of adverse events.

Of the 13 trials that met selection criteria, 11 demonstrated sub-optimal study design with inadequate blinding, inadequate trial length, inadequate sample size and lack of proper analysis. Only three studies provided quantifiable data about tolerability and adverse events, and the only probiotic to demonstrate significant improvement in IBS symptoms in appropriately designed studies was Bifidobacterium infantis 35624.

Bifidobacterium infantis 35624 showed significant improvement in the composite score of abdominal pain/discomfort, bloating/distention and bowel movement difficulty compared with placebo. A subsequent study showed that Bifidobacterium infantis 35624 demonstrated superior efficacy to the placebo for the primary outcome measure of abdominal pain/discomfort as well as for secondary measures including bloating/distention, incomplete evacuation, straining and passage of gas.

“From our discovery of the bacterium to the description of its genome and biological properties and, finally, to the clinical studies that have made this available to consumers in Align, our primary goal has been to provide accurate information on the benefits of Bifantis,” said Eamonn Quigley, MD FACG and professor of Medicine and Human Physiology and Head of the Medical School, National University of Ireland (NUI).