An analysis of randomized controlled trials evaluating the use of probiotics in the treatment of irritable bowel syndrome (IBS) indicates that only the study involving Bifantis®, Bifidobacterium infantis 35624, the active ingredient in Proctor & Gamble’s product called Align, was designed appropriately to evaluate the safety, efficacy and tolerability of probiotics for IBS.
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.