Probiotic Improves Symptoms of Irritable Bowel Syndrome

Nathalie Barrès

May 09, 2022


  • A randomized study in France demonstrated that a 30-day treatment with the probiotic Bifidobacterium longum 35624 resulted in a significant improvement in symptoms for approximately two thirds of patients with irritable bowel syndrome (IBS).

  • This improvement was also seen in patients who had the most severe symptoms at baseline.

  • In addition, patients reported that their quality of life was better after the treatment.

Why Is This Important?

Depending on which criteria are used (Rome III or Rome IV), IBS can be said to affect anywhere from 4%–10% of the population. The disorder may be responsible for impairment in quality of life, especially for the 1 in 4 patients who has the most severe form. Several lines of evidence suggest that the intestinal microbiota plays a role in the pathophysiology of IBS — and this is where the interest in probiotic therapy comes in.

That said, very few probiotics have shown efficacy in improving IBS symptoms, relative to placebo, in randomized double-blind studies. Among those that have shown efficacy is B longum 35624. The research in question shows the value of specifying the level of disease severity at baseline and of using Rome IV criteria to describe the symptoms, an approach that not many other studies have taken.


In this prospective, open-label, multicenter, observational study, adults with Rome IV IBS were monitored between November 2018 and January 2020 by gastroenterologists in private practice. Individuals who had received probiotics or antibiotics within the 2 weeks preceding enrollment were excluded from participating, as were those with a history of abdominal surgery. Patients who were enrolled in the study took one capsule of B longum 35624 (109 colony-forming units) per day for 30 days. They were advised not to change their diet during the study.

Main Results

A total of 233 patients with IBS (71.2% women; mean age, 51.4 years) were included in the evaluable population. Most were nonsmokers (87.7%) and did not consume alcohol (63.9%). Body mass index (BMI) was classified as normal in half of the patients (51.2%), as overweight in 33.5%, and as obese in 9.4%. At baseline, 15.8% had already been on a specific diet for more than 1 month and did not change it during the study period.

In more than half of the patients (54.5%), no triggering factor for IBS was identified. However, in the others, IBS was found to have been triggered by an infection (4%), a stressful event (35%), and sexual abuse (eight patients).

At baseline, the mean IBS Severity Scoring System (IBS-SSS) score was high (303 out of 500). Questionnaires brought to light the impact of IBS symptoms on quality of life (QoL) (mean IBS-QOL score: 60.2 out of 100).

After the 30-day treatment period with B longum 35624, a significant decrease in IBS severity was observed, compared with baseline. The IBS-SSS score went from 303 to 208 (P < .001). More than half of the patients (57%) experienced an overall decrease in their symptoms. The rate of severe symptoms decreased from 46.6% to 20%; moderate symptoms decreased from 48.1% to 36.1%; mild symptoms increased from 4.7% to 35.2%; and 8.7% of patients were in remission after the treatment vs 0.9% before. A significant improvement in disease severity (more than a 50-point decrease in the IBS-SSS score) was observed in 65.7% of patients, regardless of the IBS subtype.

After 30 days of treatment, a significant improvement in quality of life was noted in the patients (IBS-QOL score 68.8 vs 60.2, P < .001), and more than 6 out of 10 (63%) were satisfied with the treatment.

Of the patients treated, 4.1% reported adverse events, including flatulence, abdominal pain, abdominal distention, gastrointestinal motor disorders, and weight gain.

This article was translated from Univadis France.

For more news, follow Medscape on Facebook, Twitter, Instagram, YouTube, and LinkedIn


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.