Research project led by Bailey Hanna, MS, RDN - no affiliate links, ads or sponsored products.
Saccharomyces cerevisiae I-3856 is one of the most researched probiotics for IBS, having been assessed in five clinical trials of varying quality. Among these, three studies with a combined total of 857 participants showed minimal to no benefits compared to a placebo. (1),(2),(3) A smaller study with 92 participants reported more significant improvements in constipation, diarrhea, and abdominal pain. (4) However, this study was single-blind, meaning the clinicians knew which participants received the probiotic, and it had several reporting errors. (4) The fifth study was of very poor quality, with missing or insufficient data, and was excluded from the final analysis. (5)
Key Takeaway:
The overall evidence for the benefits of S. cerevisiae I-3856 in IBS is mostly neutral, with any significant benefits primarily seen in a lower-quality study. While some improvements in abdominal pain were noted, the consistency and magnitude of these benefits varied widely across studies. Due to these inconsistencies and the lower quality of the most promising study, we have chosen not to provide a patient handout for this probiotic.
Dose:
Trial Duration
References:
Evaluate products based on whether they transparently disclose all ingredients and their amounts, exclusively use probiotics tested in randomized placebo-controlled trials in IBS populations, and contain studied doses.
This probiotic has a range of low to high 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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Saccharomyces cerevisiae I-3856 in irritable bowel syndrome with predominant constipation
World J Gastroenterol. 2022 Jun 14;28(22):2509-2522
ADULTS
A randomized clinical trial of Saccharomyces cerevisiae versus placebo in the irritable bowel syndrome
Dig Liv Dis 2015;47(2):119–24
Randomized double blind placebo-controlled trial of Saccharomyces cerevisiae CNCM I-3856 in irritable bowel syndrome: improvement in abdominal pain and bloating in those with predominant constipation
United Eur Gastroenterol J 2016;4(3):353–62
ADULTS 18-75 years
Efficacy of Saccharomyces cerevisiae CNCM I-3856 as an add-on therapy for irritable bowel syndrome
Interl J Colorect Dis 2020;35(1):139–45
ADULTS >=18 years
Treatment of Irritable Bowel Syndrome with Saccharomyces Cerevisiae.
Journal of medical & pharmaceutical sciences 2019; Vol 3 (3): 35-44
Adults with IBS (Rome III criteria)
No data
In a population with IBS-C (Irritable Bowel Syndrome with Constipation), both the Probiotic and Placebo groups experienced an increase in bowel movement frequency and Bristol Stool Scores from week 0 to week 8 (P < 0.01 from week 1 to week 8).
However, there were no statistically significant differences observed between the two groups.
For abdominal pain responders, a significant difference between groups was found in the percentage of responders. The group receiving S. cerevisiae CNCM I-3856 had a significantly higher percentage of responders (45.1%, 101 subjects among 224 subjects with available data) compared to the Placebo group (33.9%, 74 subjects among 218 subjects with available data). This represents a 33% increase in the proportion of responders in the treated group versus the placebo group (p=0.017; Cohen’s h = 0.23, indicating a small effect size).
Both the Placebo and Probiotic groups showed significant reductions in abdominal pain scores throughout the 8 weeks of supplementation, with reductions of 24.1% and 28.7%, respectively, from baseline.
However, a nonsignificant difference was observed in the area under the curve (AUC) for abdominal pain over the second month of supplementation in subjects receiving the probiotic versus placebo [-6.3%, P = 0.073, 95% CI: -0.59 (-1.23; 0.05)], according to the between-group difference from the ANCOVA model. Similarly, no difference was reported in the AUC over the entire 8-week intervention.
Over the 8-week supplementation period, the kinetic profiles of the bloating score revealed a statistically significant decrease in both the Probiotic and Placebo groups.
The bloating score reduced by 28.4% (95% CI: 23.9-33.0) in the Probiotic group and by 24.5% (95% CI: 19.7-29.5) in the Placebo group (between week 0 and week 8, P < 0.001 in both groups, within-group differences from the ANCOVA model). However, there was no statistically significant difference between the Probiotic and Placebo groups.
Both the Placebo and Probiotic groups observed a decrease in the flatulence/borborygmi score. However, there was no significant difference between the two groups.
At the end of the intervention, the Probiotic group reported a higher overall IBS-QOL (Irritable Bowel Syndrome Quality of Life) score, indicating better quality of life, compared to the Placebo group (79.51 ± 2.34 a.u. vs. 75.65 ± 2.39 a.u. in the PP population, P = 0.047, 95% CI: 3.86 [0.52; 7.20], SMD = 0.18).
However, our independent analysis found this effect to be statistically non-significant (p > 0.05) with an effect size of 0.09. The improved quality of life in the Probiotic group translated into a mean increase in the overall IBS-QOL score of 11.9% from baseline.
The analysis of the eight domains of the IBS-QOL questionnaire showed statistically significant differences in favor of the Probiotic group for three domains.
Interference with activity [P = 0.05, 95% CI: 4.30 (0.54; 8.05), SMD = 0.18] Body image [P = 0.040, 95% CI: 3.96 (0.17; 7.75), SMD = 0.17] Food avoidance [P = 0.030, 95% CI: 5.69 (1.10; 10.28), SMD = 0.22]
All results pertain to an IBS-C population. The findings were largely neutral or statistically non-significant, except for a small but statistically significant benefit observed in the percentage of abdominal pain responders (Cohen’s h = 0.23). This was noted despite the non-significant differences between groups for the area under the curve (AUC) for abdominal pain.
Responders in this study were defined as subjects who experienced a reduction of at least 30% in their mean daily abdominal pain score from baseline (week 0) between weeks 5 and 8.
The global Quality of Life (QOL) score, along with eight subscores corresponding to different domains of QOL, were assessed at V1, V2, and at the end of the intervention. Additionally, mean stool consistency (Bristol Stool Scale scores) and the mean daily number of bowel movements were assessed each week during the intervention.
However, the reporting of many results is unclear, with some conclusions appearing questionable and potentially inaccurate.
Basic descriptive statistics for many variables are not clearly presented, leading to concerns about the validity of the findings. Despite the large sample size, the study detected negligible effects, and the unclear reporting further complicates the interpretation of the results.
See bowel habits cell
Stool frequency and stool consistency scores remained similar during the 8 weeks of treatment without intragroup and intergroup differences.
Intragroup analysis revealed a significant reduction of the score both in the probiotic and placebo groups throughout the 8 weeks of treatment period (W0–8); this led to a mean score reduction of 26.9% and 37.2% compared with baseline, respectively in the placebo and product group (p < 0.001 in both treated groups). This intergroup difference for abdominal pain/discomfort AUC during the 8 weeks of treatment was not significant (p = 0.13).
The proportion of responders, defined by an improvement of abdominal pain/discomfort, was significantly higher (p = 0.04) in the treated group than the placebo group (63% vs 47%, OR = 1.88, 95%, CI: 0.99–3.57) in the last 4 weeks of treatment. The reduction of abdominal pain/discomfort scores was higher during the first month than the second month of placebo administration (2.42 ± 1.5 vs 0.11 ± 1.49).
During the period of follow-up without product administration (W8–11), the abdominal pain/discomfort score did not vary significantly in the placebo group (p = 0.89) but continued to decrease (−0.02 ± 0.07). In contrast, this score showed a significant increase between W8 and W11 in the product group (+0.31 ± 0.02, p = 0.012
“Intragroup analysis revealed a significant reduction of bloating/distension and bowel movement difficulty scores compared with baseline both in the product and placebo groups throughout the 8-week treatment period (W0–W8) (p < 0.001 in both treated groups), but without intergroup differences.”
The effect of the product was similar across different types of IBS subjects (IBS-C, IBS-D, or IBS-M) and in the ITT (Intention-to-Treat) population. This conclusion is based on the non-significant treatment/type interaction observed in the statistical models (data not shown).
Analysis of covariance of the weekly average BSS score (stool consistency) showed a statistically significant interaction between tested product and time (p = 0.04): post hoc analysis showed a significant difference only at week 8 with average BSS score of median (IQR) 3.0 (2.0–3.9) on active versus 2.2 (1.7–3.4) on placebo (p = 0.00), diff [CI95%] = 0.447 [0.147; 0.746].
The number of complete spontaneous bowel movements showed a numerically higher value in the active group at each week of the supplementation period but this did not reach statistical significance.
“No statistically significant product effect adjusted on baseline and IBS type was noted all weeks taken together. Similar observations were reported on bloating, flatulence/borborygmi, difficulty with defecation, and composite score of IBS symptoms, with statistically significant improvements during supplementation in the two groups.”
A relief in IBS symptoms was reported by subjects as soon as the first week of supplementation (27.2% of subjects of the placebo group, 33.6% in the active group), with statistically significant improvement at the end of supplementation (57.7% of subjects of the placebo group, 60.9% in the active group at the last week of supplementation, p < 0.0001 in both groups).
Finally, quality of life was significantly improved in placebo and active groups throughout the study (p < 0.0001), with no statistically significant difference between groups.
Considering abdominal pain/discomfort score, significant decrease was observed from the beginning to the end of supplementation, in both active and placebo groups (respectively, −0.61 and −0.43, p < 0.0001 in both groups). No statistically significant product effect adjusted on baseline and IBS type was noted all weeks taken together.
Forty-seven (47) subjects out of 175 in the placebo group (26.9%) and 57 subjects out of 177 in the active group (32.2%) were considered as responders, which means that they have an improvement of 50% of the weekly average “intestinal pain/discomfort score” compared with baseline average score for at least 4 out of the last 8 weeks of the study.
However, the active product was not a statistically significant predictor of the responder status (p > 0.05). See IBS-C cell for pain improvements noted specifically in the IBS-C subtype.
In a subgroup post-hoc analysis, there was a significant treatment effect only in the IBS-C subjects. At the end of the supplementation period, significant improvement was observed in abdominal pain/discomfort, bloating, flatulence/borborygmi, and composite score in both active and placebo groups of IBS-C subjects but greater on active than placebo for abdominal pain/discomfort (p = 0.03) and bloating (p = 0.03).
A similar trend was observed with the composite score of IBS symptoms (7.3 (4.0) in the active group vs. 8.6 (4.8) in the placebo group) but this just failed to reach statistical significance. In the IBS-C subgroup, the beneficial effect of S. cerevisiae I-3856 was observed throughout the study, with significantly lower total AUC for abdominal pain/discomfort (-10.9%, diff [CI 95%] = -3.56 [-6.99; -0.13], p =0.04) and bloating (-13.6%, diff [CI 95%] = -4.44 [-7.71; -1.18], p = 0.01) in the active group, compared to placebo group.
The composite score of IBS symptoms similarly demonstrated significantly lower total AUC in the active group, in comparison to the placebo group (-11.0%, diff [CI 95%]= -12.46 [-23.76; -1.16], p = 0.03) Total AUC of quality of life was positively correlated to the AUC of pain/discomfort (r = -0.28887, p = 0.05). There was, however, no statistical difference in the proportion of responders in the active (22.0%) and in the placebo group (21.4%). For further details regarding stool form and frequency in the IBS-C group, please see the constipation cell.
Quality of life was significantly improved in placebo and active groups throughout the study (p < 0.0001), with no statistically significant difference between groups.
In a subgroup post-hoc analysis, a significant treatment effect was observed only in the IBS-C subjects. At the end of the supplementation period, both the active and placebo groups of IBS-C subjects showed significant improvements in abdominal pain/discomfort, bloating, flatulence/borborygmi, and composite scores, with greater improvements in the active group for abdominal pain/discomfort (p = 0.03) and bloating (p = 0.03).
A similar trend was observed for the composite score of IBS symptoms, with a score of 7.3 (4.0) in the active group versus 8.6 (4.8) in the placebo group, though this difference just failed to reach statistical significance.
In the IBS-C subgroup, the beneficial effect of S. cerevisiae I-3856 was consistent throughout the study, with significantly lower total AUC for abdominal pain/discomfort (-10.9%, difference [95% CI] = -3.56 [-6.99; -0.13], p = 0.04) and bloating (-13.6%, difference [95% CI] = -4.44 [-7.71; -1.18], p = 0.01) in the active group compared to the placebo group. The composite score of IBS symptoms also demonstrated a significantly lower total AUC in the active group compared to the placebo group (-11.0%, difference [95% CI] = -12.46 [-23.76; -1.16], p = 0.03).
The total AUC of quality of life was positively correlated with the AUC of pain/discomfort (r = -0.28887, p = 0.05). However, there was no statistical difference in the proportion of responders between the active (22.0%) and placebo (21.4%) groups.
For further details regarding stool form and frequency in the IBS-C group, please see the constipation cell.
There were no significant improvements compared to placebo for abdominal pain/discomfort, bloating, flatulence/borborygmi, composite score of IBS symptoms, or spontaneous bowel movements in the IBS-D participants.
There were no significant improvements compared to placebo for abdominal pain/discomfort, bloating, flatulence/borborygmi, composite score of IBS symptoms, or spontaneous bowel movements in the IBS-M participants.
In subjects with diarrhea-predominant IBS, stool consistency improved significantly more in the Saccharomyces cerevisiae CNCM I-3856 group compared to the placebo group. During the 4th week, scores were 4.38 ± 0.75 vs. 5.34 ± 0.97 (p < 0.001), and at the 8th week, scores were 4.28 ± 0.73 vs. 5.28 ± 1.00 (p < 0.001; Cohen’s d = 1.57).
For subjects with mixed-type IBS, stool consistency improvements were assessed based on their predominant symptoms. Among those with diarrhea at recruitment, significant improvement in stool consistency was seen during the 4th week in the Saccharomyces cerevisiae CNCM I-3856 group (4.25 ± 0.5) compared to the placebo group (6 ± 0.82, p = 0.01). This improvement persisted to the end of the 8th week (4.25 ± 0.5 vs. 6 ± 0.56, p = 0.01).
During the 4th week of treatment, subjects with IBS-C in the Saccharomyces cerevisiae group (CNCM I-3856) experienced significant improvement in stool consistency, with scores of 3.60 ± 0.70 compared to 2.60 ± 0.97 in the placebo group (p = 0.016). This improvement continued into the 8th week, with scores of 3.80 ± 0.63 for the Saccharomyces cerevisiae group versus 2.70 ± 1.06 for the placebo group (p = 0.011; Cohen’s d = 1.05).
Among IBS-M subjects with constipation at recruitment, significant improvement began from the second week of Saccharomyces cerevisiae CNCM I-3856 administration (2.63 ± 0.73 vs 1.33 ± 0.53, p = 0.045). This improvement persisted through the 4th week, with scores of 3.45 ± 0.58 in the Saccharomyces cerevisiae group compared to 1.33 ± 0.64 in the placebo group (p = 0.004), and continued to the end of the 8th week (3.56 ± 0.75 vs 1.62 ± 0.23, p = 0.009).
See Diarrhea and Constipation cells
Intergroup analysis showed that the Saccharomyces cerevisiae CNCM I-3856 group experienced a significant reduction in abdominal pain scores compared to the placebo group during the 4th week (1.90 ± 0.86 vs. 2.45 ± 0.88, p = 0.003; Cohen’s d = 0.93) and at the end of the treatment period (1.60 ± 0.79 vs. 2.36 ± 0.84, p < 0.001).
The intragroup analysis also indicated a significant reduction in abdominal pain scores from baseline to the 4th week in the Saccharomyces cerevisiae group (1.41 ± 0.767 vs. 0.363 ± 0.65, p < 0.001) and from baseline to the end of the treatment period (1.708 ± 0.92 vs. 0.45 ± 0.697, p < 0.001). For constipation-predominant IBS, there was a significant reduction in abdominal pain scores by the 4th week (p = 0.017) and the end of the treatment period (p = 0.017; Cohen’s d = 1.28). In diarrhea-predominant IBS, significant improvements were seen at both the 4th week (1.91 ± 0.86 vs. 2.62 ± 0.94, p = 0.003) and the 8th week (1.63 ± 0.79 vs. 2.52 ± 0.91, p < 0.001; Cohen’s d = 1.05).
For mixed-type IBS, reported improvements in abdominal pain scores at the 4th and 8th week were not statistically significant in our independent analysis.
For subtype specific effects for IBS-M, IBS-C, and IBS-D see cells for abdominal pain, constipation, and diarrhea.
The study divided subjects into two groups. Group 1 (48 participants) received standard IBS treatment for 2 weeks plus a placebo twice daily for 8 weeks. Group 2 (52 participants) received the same standard treatment plus Saccharomyces cerevisiae CNCM I-3856 capsules twice daily for 8 weeks. Standard IBS treatment varied: antidiarrheal loperamide for diarrhea-predominant IBS, antispasmodic dicyclomine for constipation-predominant IBS, and treatment based on symptoms for mixed-type IBS.
Subjects were further subgrouped into IBS-D (diarrhea), IBS-C (constipation), and IBS-M (mixed).
There were inconsistencies in reported abdominal pain results, with differing effect sizes depending on the assessed subtype. The most pronounced effect size was reported for each category. The treatment group showed a much lower standard deviation in abdominal pain at baseline, which we suspect may have been a reporting error. These assessments were self-reported by participants who were blinded, while clinicians were not. The inconsistencies in abdominal pain results suggest possible reporting errors. Reporting was sloppy.
See distention/bloating cell regarding bowel movement difficulty
Abdominal pain/discomfort scores, measured on a scale from zero (no symptoms) to seven (severe symptoms), showed a significant reduction in the probiotic groups over the 4-week treatment period (W0–4). The mean score reduction was 130 (73.4%) in the experimental group compared to 47 (27.64%) in the control group, with a p-value of less than 0.001, indicating statistical significance.
Improvement of gastrointestinal symptoms was significantly higher in the product group compared to the placebo group. This included symptoms such as abdominal pain/discomfort, bloating/distension, and bowel movement difficulty, along with stool modifications. The treated group showed a p-value of less than 0.001, and the ratio between groups was 130 (73.4%) in the product group versus 47 (27.64%) in the placebo group.
The study was disqualified from the database due to several critical issues. Essential study details were missing, and the overall quality of writing was poor, making it difficult to understand. There were no measures of variability reported, and despite being measured, stool data and microbial concentrations were not included in the report. Additionally, the term “mean response rate” was ambiguous; we assumed it referred to abdominal pain for calculation purposes. The data on bloating lacked sufficient statistics to calculate the effect size. These numerous deficiencies made it impossible to accurately assess the study, leading to its exclusion from the database.