December 07, 2016
2 min read

Probiotic used in IBS not superior to placebo for improving GI symptoms in general population

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Bifidobacterium infantis 35624, a probiotic often used to treat patients with irritable bowel syndrome, was not superior to placebo for improving abdominal discomfort and bloating in a healthy non-patient population studied in a double blind randomized controlled trial.

“Previous studies have investigated the health benefits of the probiotic bacteria [B. infantis 35624; Align, Procter & Gamble] in patients with IBS and have shown improvement in IBS symptoms including abdominal pain and discomfort and abdominal bloating and distension compared to placebo,” investigators wrote. “While it is important to determine the health benefits of a specific probiotic in patients with IBS, it is also reasonable to determine the health benefits of the same probiotic strain/product in a generally healthy population.”

The researchers therefore evaluated the efficacy of this probiotic strain in “non-patients” who had abdominal discomfort and bloating at least twice per week for at least 3 months, but did not see a doctor or receive a prescription for their symptoms in the past year.

They recruited 302 of these non-patients through an advertisement to the general population, and randomly assigned them to receive the probiotic or placebo for 4 weeks after a 2-week placebo run-in period. During this time, they evaluated changes in symptom severity and frequency across three visits at 10 U.S. sites.

The final analysis included 275 participants (mean age, 42 years; 79% women; 74% white), 141 of whom received the probiotic and 151 placebo.

Both regimens were well tolerated, and both study arms experienced significant improvements in abdominal discomfort and bloating (P < .05), but there were no significant differences in mean symptom severity scores between groups for either symptom during all 4 weeks of the intervention. However, the probiotic group was 72% more likely to have abdominal bloating-free days compared with the placebo group (P < .05).

“It is possible that the lower impact of these symptoms in ‘non-patient’ subjects led to a ‘floor effect’ where the changes in symptoms of abdominal discomfort and bloating were too minimal or required a larger sample size to be detectable,” the researchers wrote. “Another possibility is the high placebo response rate observed in interventional studies of functional GI symptoms.”

Thus, they concluded that while there is no evidence that this probiotic strain benefits non-patients, “it cannot be excluded based on the current study due to its limitations, and this question required further investigation.” – by Adam Leitenberger

Disclosures: The researchers report various financial relationships with Procter & Gamble.