Saccharomyces boulardii (SB) is a non-pathogenic strain of probiotic yeast with a wide range of clinical applications, including antibiotic-associated diarrhoea, Clostridium difficile and Helicobacter pylori infections, and small intestinal bacterial overgrowth (SIBO), to name a few.¹

SB synthesises trophic substances such as polyamines, digestive enzymes, and secretory IgA to support the proliferation and differentiation of enterocytes, which provide immunological and anti-inflammatory support to the intestinal epithelium.²

 Clinically effective dose: Starting at 200 mg twice daily, up to 500 mg twice daily.

• Duration: 4 to 8 weeks.
• Form: Saccharomyces cerevisiae (boulardii).
• Drug interactions: None known, however, Saccharomyces boulardii may theoretically interact with antifungals, reducing the efficacy of the probiotic.³
• Safe dosing: Up to 4000 mg per day has been safely used for 3 to 10 days.⁴

 

Small Intestinal Bacterial Overgrowth (SIBO)

SIBO is characterised by an increased number and/or an abnormal type of bacteria within the small intestine and is associated with a variety of gastrointestinal complaints including, diarrhoea, abdominal pain, flatulence, abdominal distension, and malabsorption of nutrients. While antibiotics are considered an effective treatment for SIBO they destroy pathogenic and non-pathogenic flora, including bacterial probiotics. SB has anti-inflammatory, antitoxin and antibiotic resistance actions making it the ideal probiotic for use in patients with SIBO.

Study Overview

In an open pilot clinical trial by García‑Collinot et al. 2020, researchers set out to evaluate the efficacy and safety of SB versus metronidazole (M) versus M + SB in reducing SIBO and related gastrointestinal symptoms in systemic sclerosis (SSc). Forty patients with SIBO were randomised into three groups: M group, metronidazole 500 mg twice daily for 7 days; SB group, Saccharomyces boulardii 200 mg twice daily for 7 days; M + SB group, metronidazole 500 mg plus Saccharomyces boulardii 200 mg twice daily for 7 days with an additional 7 days with Saccharomyces boulardii. All treatments were administered over 2 months on the first week (Group M or Group SB), or during the first and second weeks (Group M + SB) of each month, and for the remainder of the month there was no intervention. The hydrogen breath test was used to assess the presence of SIBO, in addition to a questionnaire that was used to measure gastrointestinal symptoms.

Primary Outcomes – SIBO Eradication

After 2 months of treatment, SIBO was eradicated in 55% of the M + SB group, 33% of the SB group, and 25% of the M group (Figure 1). Furthermore, results found reduced gastrointestinal symptoms (diarrhoea, abdominal pain and gas/bloating/flatulence) in the SB and M + SB groups, compared to no changes in the M group.

Researchers concluded that while metronidazole treatment was partially effective in eradicating SIBO, SB monotherapy or in combination with medication, improves the gastrointestinal outcomes to a greater extent.

Figure 1. Prevalence of SIBO at the baseline (B = basal), first (1M) and second month (2M) after the intervention. Data presented in percentage of patients with SIBO.

Gastrointestinal Symptoms

At the conclusion of the trial, researchers found the following changes in gastrointestinal symptoms (see Table 1):

• SB group experienced decreases in gastroesophageal reflux, diarrhoea, abdominal pain, and gas/bloating/flatulence;
• M + SB group had decreased abdominal pain and gas/bloating/ flatulence; and
• M group remained unchanged in almost all parameters except for an increase in abdominal pain and gas/bloating.

Table 1. Gastrointestinal symptoms before and after treatment.

Conclusion

In the present study, 2 months of treatment with SB or M + SB showed improved eradication of SIBO symptoms, reduced hydrogen production (determined via hydrogen breath test) and reduced gastrointestinal symptoms compared to M alone. While this study looked at the effects of SB for SIBO in patients with systemic sclerosis, the results can be used to support the use of SB in patients suffering SIBO broadly. Based on this study, practitioners can consider prescribing SB at doses starting at 200 mg twice daily for 4 to 8 weeks in patients presenting with gastrointestinal complications due to SIBO. This can be increased to 500 mg twice daily in those with ongoing gastrointestinal symptoms.

 

References

1. McFarland, L., Systematic review and meta-analysis of Saccharomyces boulardii in adult patients. World J Gastroenterol, 2010. 16(18): p. 2202-22.
2. García-Collinot G, Madrigal-Santillán EO, Martínez-Bencomo MA, et al. Effectiveness of Saccharomyces boulardii and metronidazole for small intestinal bacterial overgrowth in systemic sclerosis. Digestive diseases and sciences. 2020;65(4):1134-43.
3. Mikawlrawng K, Kumar S, Bhatnagar K. Drug interactions, safety and efficacy of probiotics. Asian J. Med. Health. 2016;1:1-8.
4. Szajewska, H., M. Kołodziej, and B. Zalewski, Systematic review with meta-analysis: Saccharomyces boulardii for treating acute gastroenteritis in children-a 2020 update. Aliment Pharm Ther, 2020. 51(7): p.678-688.