People with IBS tend to have low diversity and dysbiosis (imbalance in gut microbiota), which is considered to play a key role in the disease pathophysiology and associated with symptom severity.
Probiotics of the Lactobacillus and Bifidobacterium species are believed to potentially stimulate a beneficial modulation of gut microbiota that has been altered due to IBS through several mechanisms.
These include inhibition of pathogen adhesion to the gut epithelia, improvement in gut barrier function and immunity, anti-inflammatory effects, and enhancement of the gut-brain axis.
To investigate the effect of human gut-derived multi-strain probiotics on IBS severity and quality of (QOL), an open-label, observational study was conducted at Hallym University Kangnam Sacred Heart Hospital in Seoul, South Korea.
A total of 44 participants aged above 19 years were prospectively enrolled between September and December 2022.
The participants had been diagnosed with IBS according to the ROME IV criteria, which comprise recurrent abdominal pain (average of at least 1 day per week in the last three months), and abdominal pain related to defecation, change in stool frequency, and/or change in stool appearance.
They orally consumed a probiotics product containing six strains of Lactobacillus gasseri, Lactobacillus rhamnosus, Bifidobacterium longum, Bifidobacterium breve, Bifidobacterium bifidum, and Bifidobacterium lactis at a daily dose of 1 × 1010 CFU for four weeks.
The probiotics were obtained from healthy human gut.
The IBS-severity scoring system (IBS-SSS) includes five subscore visual analogue scales — abdominal pain severity (IBS-SSS1), abdominal pain frequency (IBS-SSS2), abdominal discomfort severity (IBS-SSS3), dissatisfaction with bowel habits (IBS-SSS4), and life interference in general (IBS-SSS5).
The total score ranges from 0 to 500. Those with a score of more than 75 were classified as in remission, 75 to 175 as mild disease, 175 to 300 as moderate disease, and 300 or more as severe disease.
Compared to baseline, the participants’ IBS-SSS score significantly improved after two and four weeks (−27.1 ± 32.8 and −101.8 ± 76.9 respectively).
Improvement in the IBS-SSS1 subscore was also observed in 29.5% and 61.4% of participants at weeks two and four respectively.
Furthermore, a marked increase in total IBS-QOL score, calculated based on a questionnaire, was observed in 27.3% and 63.6% of participants at weeks 2 and 4 respectively. The improvement was found mainly in those with moderate-to-severe IBS.
No severe adverse effects resulted, although two participants reported diarrhoea and bloating within two weeks of the study. The symptoms resolved within four weeks.
“This study showed that human gut-derived multi-strain probiotics are effective and safe. The IBS-SSS score significantly improved in approximately 60% of the participants, while changes in the IBS-SSS1 subscore reflected the study product’s ability to reduce severity of abdominal pain. This is consistent with previous studies indicating that microbiome modulation therapy has a notable effect on IBS symptoms and QOL,” the authors wrote.
Further research for optimal effects
IBS is a chronic functional gastrointestinal disorder whose symptoms are known to impact QOL, especially for people with moderate-to-severe disease.
“Even if IBS-related symptoms improve, treatment that includes dietary restrictions, such as low-FODMAP diet and gluten-free diet, can affect QOL. Human gut-derived multi-strain probiotics supplementation could possibly enhance the QOL of patients since they won’t have to change their diet.”
Although past studies have reported similar benefits of multi-strain probiotics in IBS patients, there is still debate on the cause of differences in clinical outcomes between single-strain and multi-strain probiotics.
As such, the researchers stressed that more research is necessary to evaluate the reasons for the differing efficacy, as well as the effect of multi-strain probiotics on dysbiosis.
It should be noted that this study had several limitations, including the prospective observational study design and participants’ disease type.
“Only a small proportion of patients with IBS-C (IBS with constipation) was included. Further large-scale RCTs are required to ensure the efficacy and safety of human gut-derived multi-strain probiotics in IBS-C patients.”
In addition, treatment duration is thought to play an important part in clinical outcomes.
“Other studies have discovered that improvement in symptoms were typically observed after four to eight weeks. Likewise, improvement at week four is significantly greater than week two in our study. To determine the optimal treatment period, there is a need to assess the changes in gut microbiome according to the duration of intervention.
“Nevertheless, our study showed a response rate that exceeded the expected 55% for both primary and secondary outcomes. Taking into consideration that the placebo effect usually does not exceed 25%, the superiority of human gut-derived multi-strain probiotics was demonstrated,” the authors concluded.
“Efficacy and safety of human gut-derived multi-strain probiotics in patients with irritable bowel syndrome: A prospective open-label observation study”
Authors: Chang Kyo Oh, et al