Collagen Supplements and Post-MBS Muscle Mass/Body Image

NCT07809152 | Recruiting

• 1 other identifier: MUDU-SBE-SS-05
• Study Type: observational
• Target: 52
• Locations: 1 country
• Sites: 1

Brief Summary

This prospective, observational cohort study aims to evaluate whether the use of collagen-containing supplements is associated with differences in muscle mass, body composition, and body image among patients who have undergone sleeve gastrectomy (SG). The study will be conducted at the General Surgery outpatient clinic of a private hospital in Bursa, Türkiye, between May 2026 and March 2027, and will enroll adult patients (aged 18-65 years) who meet current ASMBS/IFSO eligibility criteria for metabolic and bariatric surgery. Participants will be naturally allocated into two observational groups based on their own choice to use or not use collagen-containing supplements; no supplement will be provided or recommended by the study team, and no intervention will be made to participants' standard clinical care. All patients will be followed according to routine clinical practice preoperatively and at 2 weeks, 1 month, 3 months, and 6 months postoperatively. Primary outcome measures include anthropometric parameters (body weight, BMI, fat mass, fat mass percentage, fat-free mass, muscle mass, percentage of weight loss, percentage of excess weight loss, waist and hip circumference) assessed via bioelectrical impedance analysis (Tanita MC-780 MA), and body image assessed using the Turkish-validated Body Shape Questionnaire (BSQ). Secondary outcomes include biochemical parameters, comorbidities, and macronutrient intake data obtained from 3-day dietary records analyzed using the BEBİS nutrition software. The study hypothesizes that patients using collagen-containing supplements will show significant differences in muscle mass and body composition parameters compared with non-users, and that supplement use will be significantly associated with BSQ scores. A sample size of approximately 52 participants per group was calculated using G\*Power 3.1 (one-way ANOVA, Cohen's f = 0.25, α = 0.05, power = 0.80).

Conditions

Obesity & Overweight; Collagen Protein; Bariatric Surgery; Metabolic and Bariatric Surgery; Body Composition; Muscle Composition; Body Image

Keywords

Bariatric Surgery; Collagen Supplementation; Muscle Mass; Body Composition

Outcome Measures

Primary Outcomes (9)

• Change in Body Weight

  Body weight (kg) measured using a Tanita MC-780 MA device.

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

• Change in Body Shape Questionnaire (BSQ) Score

  Body image concerns were assessed using the Body Shape Questionnaire (BSQ-34), a validated instrument for the Turkish population. This 34-item self-report scale evaluates weight-related concerns and dissatisfaction with body shape over the preceding four weeks. Each item is scored from 1 (never) to 6 (always), with a total score range of 34 to 204. Higher scores indicate greater dissatisfaction with body shape, i.e., a worse outcome.

  Preoperative and postoperative 6 months

• Change in Body Mass Index (BMI)

  BMI calculated as body weight (kg) divided by height squared (m²).

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

• Percentage of Total Weight Loss (%TWL)

  Calculated as (preoperative weight - postoperative weight) / preoperative weight × 100.

  Postoperative and 6 months

• Percentage of Excess Weight Loss (%EWL)

  Calculated as (preoperative weight - postoperative weight) / (preoperative weight - ideal weight) × 100. Ideal body weight was calculated assuming a BMI of 25 kg/m².

  Postoperative and 6 months

• Change in Fat Mass

  Fat mass (kg) assessed by multi-frequency bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

• Change in Fat Mass Percentage

  Fat mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

• Change in Muscle Mass

  Muscle mass (kg) assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

• Change in Muscle Mass Percentage

  Muscle mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device.

  Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months

Secondary Outcomes (21)

• Change in Fasting Blood Glucose

  Preoperative and 6 months

• Change in Fasting Insulin

  Preoperative and 6 months

• Change in HbA1c

  Preoperative and 6 months

• Change in LDL Cholesterol

  Preoperative and 6 months

• Change in HDL Cholesterol

  Preoperative and 6 months

Study Arms (2)

1. Grup

Group/Cohort Label: Collagen Supplement Users (Kolajen Kullananlar) Description: Participants who, based on their own preference, use a collagen-containing supplement product following sleeve gastrectomy, without any intervention or recommendation from the study team.

Dietary Supplement: Collagen-containing supplement

2. Grup

Group/Cohort Label: Non-Users of Collagen Supplement (Kolajen Kullanmayanlar) Description: Participants who do not use any collagen-containing supplement product following sleeve gastrectomy, followed under routine clinical care.

Interventions

Collagen-containing supplement DIETARY_SUPPLEMENT

Collagen-containing supplement products used at the participants' own discretion following sleeve gastrectomy. The type of product, daily dosage, and duration of use were self-reported by participants

1. Grup

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adult patients aged 18-65 years who underwent sleeve gastrectomy and are under routine postoperative follow-up at the General Surgery outpatient clinic of a private hospital in Bursa, Türkiye. Eligible patients meet current ASMBS/IFSO criteria for metabolic and bariatric surgery (BMI ≥ 35 kg/m², or BMI 30-34.9 kg/m² with an obesity-related metabolic comorbidity). Participants are naturally grouped according to their own preference to use or not use a collagen-containing supplement following surgery.

You may qualify if:

• Patients with a BMI ≥ 35 kg/m², regardless of the presence of comorbidities
• Patients with a BMI of 30-34.9 kg/m² who have an obesity-related metabolic disease and are considered eligible for surgical treatment
• Patients who have undergone metabolic and bariatric surgery (MBS) in accordance with current ASMBS/IFSO guidelines (Eisenberg et al., 2022)
• Patients under regular postoperative follow-up
• Age 18-65 years

You may not qualify if:

• Inflammatory bowel disease
• History of upper gastrointestinal bleeding
• Severe psychiatric disorders
• Active cancer diagnosis
• Pregnancy or breastfeeding
• Alcohol or substance dependence
• Physical limitations preventing participation in exercise

Sponsors & Collaborators

• Mudanya University: lead

Study Sites (1)

Yıldırım Doruk Hastanesi

Bursa, Yıldırım, Turkey (Türkiye)

RECRUITING

MeSH Terms

Conditions

Obesity; Overweight

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Seher Şen, Assistant Professor

CONTACT

+905393919700; seherdalli@gmail.com

Emre Şen, Master's degree graduate

CONTACT

0 532 163 30 87

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assist. Prof. Dr.

Study Record Dates

• First Submitted: July 29, 2026
• First Posted: September 9, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): January 10, 2027
• Study Completion (Estimated): February 10, 2027
• Last Updated: September 9, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)