Prebiotics and Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a common and socially significant condition that affects millions of people worldwide, disrupting daily routines, eating habits, and overall quality of life. Despite medical advancements, treating IBS remains a challenge, as standard pharmaceutical approaches often have limited effectiveness or come with unwanted side effects.

This article is entirely based on information from the peer-reviewed scientific publication "GOS to Reduce Symptom Severity in IBS (EGIS)"—the result of a collaboration among leading researchers in the field of gastroenterology, including Dr. Lucien F. Harthoorn, PhD (Clasado Research Services Limited), and an international team of experts. The study was sponsored by Clasado and conducted in partnership with CR2O B.V., summarizing the latest findings and criteria regarding the efficacy and safety of the prebiotic galacto-oligosaccharides (GOS) in patients with IBS.

In the Q&A section below, you will find practical, patient-oriented information derived solely from this peer-reviewed scientific publication.

"Use of the study product indicated a reduction in the patients' symptoms, improvement in the patients' quality of life, and changes in patients' gut bacteria."

Expert Insights

Irritable Bowel Syndrome (IBS) is one of the most common functional gastrointestinal disorders, affecting millions of people worldwide. It is characterized by chronic and often disabling symptoms such as abdominal pain, bloating, constipation, diarrhea, or a mixed bowel pattern. Despite the widespread prevalence, treatment options are limited, and many patients face uncertainty regarding the effectiveness and safety of new therapies.

In recent years, special attention has been given to the role of the gut microbiota and the use of prebiotics—dietary supplements that stimulate the growth of beneficial bacteria. One such substance is galacto-oligosaccharides (GOS), the focus of the current study. Below are five key expert insights and scientific summaries from the publication, which may help patients and their families understand the significance of this approach and what they should be aware of.

1. What is IBS, and why is conventional treatment often insufficient?

“IBS is a highly prevalent bowel disorder, characterized by recurrent abdominal pain during bowel movements or a change in bowel habits. Typically, IBS patients experience constipation, diarrhea or a mix of constipation and diarrhea, as well as symptoms of abdominal bloating or distension. The chronic and bothersome nature of IBS symptoms negatively affects the quality of life of many patients. Because there are currently limited medical treatment options for IBS, it is important to study new treatments.”

Explanation: IBS is a widespread condition marked by recurring abdominal pain and changes in bowel habits (constipation, diarrhea, or a mix). The symptoms are chronic and often negatively impact quality of life. Because treatment options are limited, there's a growing need to explore new solutions.

2. Could balancing gut microbiota be the key to relieving IBS symptoms?

“IBS can (in part) be caused by an 'imbalance' of the bacteria residing in the intestinal tract. For instance, there may be a lower proportion of specific bacteria that are generally considered beneficial for a person’s health. The consumption of non-digestible food ingredients, such as GOS, may stimulate the growth of these beneficial bacteria.”

Explanation: Some causes of IBS may be related to an imbalance in gut microbiota—a reduction in beneficial bacteria. Consuming non-digestible dietary ingredients like GOS can promote the growth of these beneficial bacteria and potentially improve gut health.

3. What have previous clinical trials shown about GOS in IBS patients?

“The health effects of the study product (a specific GOS) used in current study was previously investigated in a small group of patients with IBS. Use of the study product indicated a reduction in the patients' symptoms, improvement in the patients' quality of life, and changes in patients' gut bacteria. It is therefore hypothesized that GOS / a specific GOS may reduce the symptom severity of patients with IBS.”

Explanation: Earlier studies using GOS in IBS patients have shown reduced symptoms, improved quality of life, and positive changes in gut microbiota. These results suggest that GOS may help lessen symptom severity in a broader patient population.

4. What symptoms and indicators are being studied in the new GOS clinical trials?

“Primary Outcome Measures: The difference in total IBS symptom severity between treatment arms as measured by mean composite IBS Symptom Severity Scale scores... Secondary Outcome Measures: Abdominal pain... Bloating... Global IBS improvement... Stool consistency... Defecation frequency... Quality of Life IBS-QOL score... Anxiety and depression...”

Explanation: New studies with GOS assess not only overall symptom severity but also specific issues such as abdominal pain, bloating, bowel frequency and consistency, quality of life, and levels of anxiety and depression. This provides a well-rounded view of GOS’s potential benefits in IBS treatment.

5. Who can participate in these studies, and what are the exclusion criteria?

“Inclusion Criteria: 1. Patients who have been diagnosed with IBS by a medically trained person/Health Care Professional (HCP)... 2. IBS diagnosis to be confirmed according to the Rome-IV criteria... Exclusion Criteria: ...Use of products marketed as prebiotics, probiotics or synbiotics within 4 weeks prior to study entry... Systemic antibiotic or antimycotic treatment within 4 weeks prior to study entry... Confirmed lactose intolerance... Severe illness(es) or medical condition(s), including gastrointestinal pathologies... Excessive alcohol consumption (>14 units per week) and/or drug abuse... Pregnancy and lactation...”

Explanation: Only patients with a confirmed diagnosis based on modern Rome-IV criteria can take part in such trials. People with other medical conditions, lactose intolerance, alcohol or drug abuse, and those who are pregnant or breastfeeding are excluded. These criteria help ensure the results are accurate and safe.

Questions and Answers

1. What is the GOS product and how is it taken? 

Answer: GOS (galacto-oligosaccharides) is a type of prebiotic—a dietary supplement that the body doesn't digest but that feeds beneficial gut bacteria. In the study, patients took one daily dose of GOS as a supplement for eight weeks, following a two-week run-in period.

2. What is GOS being compared to in the study? 

Answer: In the clinical trial, GOS is compared to a placebo—in this case, maltodextrin, which looks, tastes, smells, and dissolves like GOS but contains no active ingredient. One group receives the real prebiotic, while the other gets the placebo, without knowing which group they’re in.

3. What symptoms and measures will be monitored if I participate in a study like this? 

Answer: During the study, the following will be monitored:

• Overall IBS symptom severity (using a special scale)

• Abdominal pain

• Bloating

• Frequency and consistency of bowel movements (via the Bristol Stool Scale)

• Quality of life

• Levels of anxiety and depression

• Any side effects

• Changes in gut microbiota composition and some blood markers

4. Can I take other medications or supplements while using GOS? 

Answer: The study excludes individuals who have used prebiotics, probiotics, synbiotics, antibiotics, or antifungal medications in the past 4 weeks, or those who used laxatives or antidiarrheal medications in the last week. Any recent changes in medications or diet that affect bowel function are also not allowed before or during the study.

5. Who should NOT use GOS, according to the study criteria? 

Answer: The following individuals are excluded from participation:

• Those with lactose intolerance or diagnosed food allergies

• People with serious health conditions (including major gastrointestinal diseases, cancer, or treated autoimmune disorders)

• Those who had gastrointestinal surgery in the last 4 weeks

• Individuals who have lost more than 5% of body weight in the past 6 months

• People with excessive alcohol consumption

• Pregnant or breastfeeding women

• Those following strict diets that could affect results (e.g., vegan, low-carb, keto, gluten-free)

Conclusion 

The findings and criteria outlined in the “GOS to Reduce Symptom Severity in IBS (EGIS)” study suggest that IBS treatment is increasingly moving beyond standard medications toward a more personalized approach focused on gut microbiome profiles and the role of prebiotics like GOS. Through well-defined inclusion and exclusion criteria and precise monitoring of symptoms, quality of life, and side effects, the study provides a reliable foundation for patients, their families, and healthcare providers to make informed decisions about future treatment options.

All the answers provided below are designed to address the most important practical questions that any patient with IBS might have while searching for new, science-backed ways to manage their symptoms.

Source: 

GOS to Reduce Symptom Severity in IBS (EGIS) – ClinicalTrials entry (NCT05157061): https://clinicaltrials.gov/study/NCT05157061