The Impact of Probiotics on Bariatric Treatment Outcomes (PROBE)

Study on the Impact of Probiotics on Postoperative Gastrointestinal Symptoms and Gut Microbiota After Sleeve Gastrectomy: A Randomized-Control Trial

The planned study aims to assess whether probiotics improve the quality of life in patients during the early postoperative period following sleeve gastrectomy, and whether they influence the absorption of micro- and macronutrients.

Patients eligible for inclusion will have a BMI of 40 kg/m² or higher and must have successfully completed the qualification process for sleeve gastrectomy. Exclusion criteria include chronic gastrointestinal diseases, antibiotic use within 4 weeks prior to surgery, and lack of consent to participate in the study.

On the day before surgery, a stool sample will be collected from each patient for microbiological analysis to assess the composition of gut bacteria. Patients will then undergo sleeve gastrectomy using a standard surgical technique.

After the operation, participants will be randomized into two groups. The first group will receive probiotics containing Bifidobacterium animalis AMT30, Bifidobacterium breve AMT32, and Lactobacillus plantarum AMT14. These strains are deposited in the Polish Collection of Microorganisms at the Polish Academy of Sciences in Wrocław and are protected by Polish, European, and U.S. patents. The second group will receive a placebo.

As part of follow-up, stool samples will be collected again one month and three months after surgery for comparative microbiological analysis.

Study Overview

• Status: Active, not recruiting
• Conditions: Obesity &Amp; Overweight
• Intervention / Treatment: Other: Diet; Dietary supplement: Probiotic

• Study Type: Interventional
• Enrollment (Estimated): 200
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Poland
  • Olsztyn, Poland, 10-015
    • University of Warmia and Mazury

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age over 18 years.
2. BMI over 40 kg/m² or over 35 kg/m² with obesity-related comorbidities.
3. Successful qualification for sleeve gastrectomy.
4. Informed consent to participate in the study.

Exclusion Criteria:

1. Age under 18 years.
2. Chronic gastrointestinal diseases.
3. Use of antibiotic therapy within 4 weeks prior to surgery.
4. Lack of consent to participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Other: Diet; Placebo
Active Comparator: Control	Dietary supplement: Probiotic; Probiotics containing Bifidobacterium animalis AMT30, Bifidobacterium breve AMT32, and Lactobacillus plantarum AMT14.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of the impact of probiotics on the resolution of constipation after sleeve gastrectomy	The primary outcome of the study is to assess the effect of probiotics on the frequency of defecation in the early weeks following surgery. The patient would be asked whether constipation occurred (yes or no).	one and three months after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of the impact of probiotics on gastrointestinal symptoms after SG	The secondary outcome of the study is to assess the effect of probiotics on the frequency of defecation in the early weeks following surgery. The patient would be asked about the number of stools passing per week.	one and three months after surgery
Assessment of the impact of probiotics on gastrointestinal symptoms after SG	The secondary outcome of the study is to assess the effect of probiotics on the frequency of defecation in the early weeks following surgery. The patient would be asked about the subjective assessment of the ease of defecation. A Likert scale of 1-5 was used, where 1 indicated great difficulty with defecation, and 5 indicated no difficulty with defecation.	one and three months after surgery
Assessment of the impact of probiotics on gastrointestinal symptoms after SG	The secondary outcome of the study is to assess the effect of probiotics on the frequency of defecation in the early weeks following surgery. The patient would be asked about the feeling of bowel movement completeness. A Likert scale of 1-5 was used, where 1 indicated a complete feeling of incomplete defecation, and 5 indicated a complete feeling of defecation.	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: Hemoglobin (Hb): g/dL	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: Creatinine: mg/dL	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: Total Protein: g/L	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: Total Cholesterol: mg/dL	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: HbA1c: %	one and three months after surgery
Metabolic changes after the probiotics use in patients after SG	The secondary aim is to evaluate laboratory tests to identify any metabolic changes associated with probiotic use. It would be: Ferritin: µg/L (ng/mL)	one and three months after surgery

Collaborators and Investigators

• Sponsor: University of Warmia and Mazury in Olsztyn

Study record dates

Study Major Dates

• Study Start (Actual): July 10, 2025
• Primary Completion (Estimated): July 10, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: July 10, 2025
• First Submitted That Met QC Criteria: November 28, 2025
• First Posted (Actual): December 2, 2025

Study Record Updates

• Last Update Posted (Actual): December 2, 2025
• Last Update Submitted That Met QC Criteria: November 28, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: obesity; constipation; sleeve gastrectomy
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Signs and Symptoms, Digestive; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Constipation; Dietary Supplements; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Nutritional Physiological Phenomena; Probiotics; Diet
• Other Study ID Numbers: 1/2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No