Research project led by Bailey Hanna, MS, RDN - no affiliate links, ads or sponsored products.
We identified six clinical trials evaluating the effects of Saccharomyces boulardii CNCM I-745 in individuals with Irritable Bowel Syndrome (IBS). Unfortunately, three of these trials were inaccessible, (1,2,3) and one was automatically disqualified due to its open-label design. (4) The remaining two studies were also excluded from our analysis due to significant issues with evidence quality. (5,6) Here’s a closer look at the remaining two trials and the reasons for their disqualification:
This study was disqualified primarily due to significant methodological issues. It was underpowered, meaning it didn’t include enough participants to reliably detect differences between the treatment and control groups. Additionally, the researchers used percentage changes to report their findings, which is problematic because percentage changes require a ratio measurement scale, but they applied this to interval-level data. This mismatch makes the inferential statistics reported in the study essentially meaningless.
We recalculated the data and found that the study authors incorrectly reported the significance of some findings. For instance, they deemed the reduction in loose/watery stools insignificant, whereas our recalculations showed it was significant (p = 0.024; Cohen’s d = 0.56). Conversely, they reported significant improvements in IBS quality of life (IBS-QOL) that our analysis found to be statistically insignificant (p = 0.097). Due to these critical flaws, we disqualified this study from our database.
This study was disqualified due to potential confounding factors and poor reporting practices. Both the probiotic and placebo were administered alongside ispaghula husk, a common treatment for IBS symptoms, making it difficult to isolate the effects of the probiotic. Additionally, the study reported a high rate of adverse effects in both groups—51% in the treatment group and 43% in the placebo group. Notably, some symptoms, such as straining, worsened in the treatment group while improving in the placebo group.
The study also failed to report descriptive statistics for IBS-QOL, providing only p-values, which we found to be insufficient for an independent analysis. This sloppy reporting, combined with the potential confounding from ispaghula husk and the adverse effects, led us to disqualify this study as well.
Out of the two accessible placebo-controlled trials of S. boulardii CNCM I-745, both were disqualified due to poor evidence quality. Therefore, based on the available evidence, we do not recommend the use of S. boulardii CNCM I-745 for IBS at this time.
None
References:
Evaluate them based on whether they transparently disclose all ingredients and their amounts, exclusively use probiotics tested in randomized placebo-controlled trials in IBS populations, contain the dosages studied, and are free from gastrointestinal irritants.
This probiotic has low quality studies in IBS populations supporting it. View our evidence evaluation framework to learn how we assess the quality of studies.
Add condition
A randomized, double-blind, placebo-controlled multicenter trial of Saccharomyces boulardii in irritable bowel syndrome: effect on quality of life
J Clin Gastroenterol 2011;45(8):679–83
ADULTS 20-65 years
There was no significant % change rate from baseline till week 4 in scores for loose/watery stool (p=0.15) or urgency(p=0.77) between the probiotic and placebo groups.
There was no significant % change rate from baseline till week 4 in scores for hard/lumpy stool (p=0.77), straining (p=0.28), or sense of incomplete evacuation (p=0.19) between the probiotic and placebo groups.
See cells for constipation and diarrhea; there was no significant % change rate from baseline till week 4 in scores for mucus in stool (p=0.89) between the probiotic and placebo groups.
There was no significant % change rate from baseline till week 4 in scores for total IBS symptom scores (p=0.66) between the probiotic and placebo groups.
There was no significant % change rate from baseline till week 4 in abdominal pain scores (p =0.13) or abdominal discomfort scores (p=0.19) between the probiotic and placebo groups.
There was no significant % change rate from baseline till week 4 in scores for bloating (p=0.72) between the probiotic and placebo groups.
There was no significant % change rate from baseline till week 4 in scores for “passage of gas” (p=0.69) between the probiotic and placebo groups.
No data
The overall improvement in IBS-QOL was higher in S. boulardii group than placebo (15.4% vs 7.0%; P<0.05). All eight domains of IBS-QOL were significantly improved in S. boulardii group.