Research project led by Bailey Hanna, MS, RDN - no affiliate links, ads or sponsored products.
One randomized, placebo-controlled trial aimed to evaluate the effects of this 4-strain probiotic blend on individuals with IBS. While the study initially reported significant improvements in symptom severity, quality of life, days with pain, and satisfaction with bowel habits for those taking the probiotic compared to the placebo group, we ultimately disqualified this study due to several key issues affecting its reliability.
Firstly, participants in the probiotic group started with more severe IBS symptoms at the baseline, which provided a greater margin for improvement compared to the placebo group. This imbalance could have skewed the results. Additionally, the study involved a small number of participants, making it underpowered and less likely to produce statistically significant findings that are truly reflective of the broader IBS population.
Moreover, the reported differences between the groups seemed disproportionately strong considering the number of participants and effect sizes. Without access to the original calculations, we couldn’t verify these statistics, adding to our concerns about the study’s validity.
Key Takeaway:
This 4-strain probiotic has been disqualified from our database due to poor evidence quality. The current evidence is insufficient to recommend the use of this probiotic at this time.
Dose:
None
Reference:
Williams EA, Stimpson J, Wang D, et al. Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study. Aliment Pharmacol Ther 2009; 29: 97–103. S
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.
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Clinical trial: a multistrain probiotic preparation significantly reduces symptoms of irritable bowel syndrome in a double-blind placebo-controlled study
Aliment Pharmacol Ther 2009; 29: 97–103
ADULTS
No data
There was significantly improved satisfaction with bowel habits for the probiotic subjects over the placebo group at 6 weeks (P = 0.0422; difference between groups: −11.05; 95% CI: −21.70 to −0.39).
There were no statistically significant differences at any other study time-point during or after the intervention.
Comparison of the effectiveness of the probiotic in the presence of significant placebo effect in this study showed a significant difference in the Symptom Severity Score in favor of the probiotic at 6 weeks (P = 0.0347; difference between groups: −47.82; 95% CI: −92.18 to −3.4) and 8 weeks (P = 0.0217; difference between groups: −52.73; 95% CI: −97.67 to −7.78) but by 2 weeks post-intervention, no significant differences could be detected between the probiotic and placebo groups.
Of note, the IBS symptom severity scores were approximately 11% more severe at baseline in the probiotic group compared to the placebo group, which potentially could have altered results in favor of the probiotic. *
The number of days with pain recorded was significantly lower in the probiotic group at week 10 (post-intervention) than in the placebo group (P = 0.0448; difference between groups: −10.97; 95% CI: −21.69 to −0.26). But there was no significant change in abdominal pain severity compared to the placebo group.
Both the placebo and probiotic group experienced reductions in the symptom of bloating throughout the intervention period, though there were no statistically significant differences between the groups.
Significant improvements in quality of life were recorded for those receiving the probiotic at the end of the intervention period (P = 0.0068; difference between groups: −13.58; 95% CI: −23.38 to −3.78 at week 8).