Research project led by Bailey Hanna, MS, RDN - no affiliate links, ads or sponsored products.
A single randomized, double-blind, placebo-controlled trial investigated the effects of Lactobacillus salivarius UCC4331 in adults with IBS. Participants received the probiotic via a malted milk beverage at a dose of 10 billion CFU/day. However, the quality of evidence from this study was compromised due to several critical shortcomings:
What Were the Results?
The trial found that L. salivarius UCC4331 did not significantly improve:
Interestingly, the only significant benefit was observed in week 2 of the 8-week trial, specifically for abdominal pain. However, this improvement was not sustained throughout the study period.
Key Takeaway
Based on this one clinical trial, L. salivarius UCC4331 does not appear to be superior to a placebo in managing IBS symptoms. Therefore, current evidence does not support recommending L. salivarius UCC4331 for IBS management.
Dose:
None
References:
O’Mahony L, McCarthy J, Kelly P, et al. Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles.Gastroenterol 2005;128(3):541–51.
There is insufficient evidence demonstrating benefits for IBS with this probiotic. Therefore, we do not provide guidance on finding a commercial product containing this strain/blend.
This probiotic has low to moderate quality studies in IBS populations supporting it. View our evidence evaluation framework to learn how we assess the quality of studies.
Add condition
Lactobacillus and bifidobacterium in irritable bowel syndrome: symptom responses and relationship to cytokine profiles
Gastroenterol 2005;128(3):541–51
ADULTS 18-75 years
No data
For bowel movement difficulty scores, there was no significant benefit for those randomized to L salivarius UCC4331. *P < .05 vs placebo. There was no significant improvement in bowel movement consistency
The L. salivarius UCC4331 group experienced no significant reduction in composite scores compared to placebo.
For those randomized to L salivarius UCC4331, a significant benefit was only evident at week 2 alone. *P < .05 vs placebo for abdominal pain throughout the 8 week trial.
For bloating, there was no significant benefit for those randomized to L salivarius UCC4331. *P < .05 vs placebo
“For most domains, quality-of-life scores were numerically lower than those for placebo for the patients randomized to the probiotics but reached statistical significance versus placebo during the treatment phase only for health worry for bifidobacterium (at the .05 level) and dysphoria for lactobacillus (at the .10 level)”
Following treatment with B infantis 35624, PBMC cytokine levels returned to levels similar to those observed for the healthy volunteer group. In contrast, PBMC cytokine levels did not return to levels observed for healthy volunteers in the subjects with IBS who received L salivarius UCC4331 or placebo.