Effects of the Dietary Inflammatory Index on Systemic Inflammation Markers and Gastrointestinal Symptoms in Individuals With Bariatric Surgery

The goal of this observational cross-sectional study is to evaluate the relationships between the Dietary Inflammatory Index (DII), systemic inflammatory markers, and gastrointestinal symptoms in adults aged 18-65 who have undergone bariatric surgery.

The main questions it aims to answer are:

Does the inflammatory potential of the diet affect systemic inflammation levels (such as SII, CRP, and WBC) in the post-operative period?

Is there an association between the DII score and gastrointestinal symptoms (e.g., bloating, gas, abdominal pain)?

Participants who are at least three months post-bariatric surgery will provide dietary intake data to calculate DII scores, undergo blood tests to measure inflammatory markers, and complete assessments regarding their gastrointestinal symptoms.

Study Overview

• Status: Enrolling by invitation
• Conditions: Systemic Inflammation; Bariatric Surgery; Bariatric Sleeve Gastrectomy; Dietary Inflammatory Index (DII); Systemic Inflammation Markers; Inflamation
• Intervention / Treatment: Other: Observational Intervention; Other: Observetional

• Study Type: Observational
• Enrollment (Estimated): 70

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Uskudar
    • Istanbul, Uskudar, Turkey (Türkiye)
      • Istanbul Bilgi University

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Aktif International Uskudar Hospital, Istanbul, Türkiye.

Description

Inclusion Criteria:

• Adult individuals between the ages of 18 and 65,
• Having undergone bariatric surgery at least 3 months prior,
• Individuals who agreed to participate voluntarily in the study and signed the informed consent form,
• Having the cognitive ability/literacy to completely complete the food consumption record and questionnaire forms,
• Individuals with no health conditions that would prevent blood tests,
• Individuals who were regularly followed up after surgery and had no postoperative complications.

Exclusion Criteria:

• Individuals diagnosed with gastrointestinal diseases such as inflammatory bowel disease, celiac disease, or short bowel syndrome before or after bariatric surgery,
• Those with a history of diseases that could affect systemic inflammation, such as autoimmune disease, active infection, or cancer,
• Individuals regularly taking medications that could affect inflammation levels, such as corticosteroids, immunosuppressants, or anti-inflammatory drugs,
• Individuals actively or recently using probiotic supplements,
• Pregnant or breastfeeding women,
• Those with a history of chronic alcohol use or substance abuse,
• Individuals who experienced serious postoperative complications after surgery (e.g., anastomotic leak, serious infection, or conditions requiring reoperation),
• Individuals with cognitive or communication disabilities that prevented them from providing the necessary information and data to the study or who were lost to follow-up,
• Individuals with chronic organ failure,
• Individuals with a psychiatric diagnosis,
• Individuals who did not consent to their data being used for scientific purposes.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Biochemical Measurements - Fasting blood glucose	Fasting blood sugar (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning the study 1 times
Biochemical Measurement - Lipid Profile	Participants' biochemical tests (total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods at the beginning of the study from blood samples taken by a nurse after at least 12 hours of fasting and without consuming alcohol for 24 hours before.	at the beginning the study 1 times
Biochemical Measurements - Liver Enzymes	Participants' liver enzymes tests (ALT, AST, and ALP) (IU) will be analyzed in the hospital biochemistry laboratory using routine methods at the beginning of the study from blood samples taken by a nurse after at least 12 hours of fasting and without consuming alcohol for 24 hours before.	at the beginning the study 1 times
Biochemical Measurements - CRP	Participants' c-reactive protein tests (CRP) (mg/L) will be analyzed in the hospital biochemistry laboratory using routine methods at the beginning of the study from blood samples taken by a nurse after at least 12 hours of fasting and without consuming alcohol for 24 hours before.	at the beginning the study 1 times
Anthropometric Measurements - Body weight (kg)	At the beginning and end of the study, body weights (kg) will be measured using a bioelectrical impedance (BIA) device with a sensitivity of 50 grams in accordance with the measurement standards.	at the beginning the study 1 times
Anthropometric Measurements - Height	Height (cm) will be measured with a stadiometer in the Frankfort plane, standing and with the head upright.	at the beginning the study 1 times
Body Mass Index	The body mass index (BMI) of the participants will calculated according to the body weight (kg) / height (m)2 formula.	at the beginning the study 1 times
Body Mass Index Classification	The body mass index (BMI) of the participants is classified according to the World Health Organization (WHO) criteria. BMI ≤ 18.5 kg/m2 is underweight, between 18.5-24.99 kg/m2 is normal, ≥ 25 kg/m2 is overweight, and ≥ 30 kg/m2 is obese.	at the beginning the study 1 times
Anthropometric Measurements - Fat Mass	At the beginning and end of the study, body fat mass (kg) analysis will be performed using a bioelectrical impedance (BIA) device, paying attention to measurement standards.	at the beginning the study 1 times
Anthropometric Measurements - Fat ratio calculation	At the beginning and end of the study, body composition analyses will be performed using a bioelectrical impedance (BIA) device with measurement standards. According to the BIA analysis, fat percentage (%) will be calculated as the ratio of total body fat weight to total body weight.	at the beginning the study 1 times
Anthropometric Measurements - Fat-free mass	At the beginning and end of the study, fat-free mass (kg) will be analyzed using a bioelectrical impedance (BIA) device, paying attention to measurement standards.	at the beginning the study 1 times
Anthropometric Measurements - Muscle mass	At the beginning and end of the study, lean muscle mass (kg) will be analyzed using a bioelectrical impedance (BIA) device, paying attention to measurement standards.	at the beginning the study 1 times
Anthropometric Measurements - Total body water	At the beginning and end of the study, total body water (kg) will be analyzed using a bioelectrical impedance (BIA) device, paying attention to measurement standards.	at the beginning the study 1 times
Biochemical Measurements - HbA1c	HbA1C will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning the study 1 times
Biochemical Measurements - Fasting Insulin	Fasting insulin levels (IU) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study
Biochemical Measurements - Urea	The blood urea (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - Serum Albumine	Serum Albumine (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - TSH	TSH (mUI/mL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - Free T4	Free T4 (ng/dl) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - Serum Electrolyte Level	Serum sodium, potassium and calcium (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - Creatinine	Creatinine levels (mg/dL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - White blood cell (WBC)	The white blood cell levels (mcL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study
Biochemical Measurements - Neutrophil count (NEU)	Neutrophil count (NEU) (mcL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study
Biochemical Measurements - Platelet (PLT)	Neutrophil count (NEU) (mL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study
Biochemical Measurements - Lymphocyte count (LYM)	Lymphocyte count (LYM) (mcL) will be analyzed in the hospital biochemistry laboratory using routine methods from blood samples taken by a nurse at the beginning of the study.	at the beginning of the study 1 times
Biochemical Measurements - Systemic Immune Inflammation Index (SII)	Systemic Immune Inflammation Index (SII) will calculates Platelet count X Neutrophil count/Lymphocyte count.	at the beginning of the study
Prognostic Inflammatory Index (PNI)	Prognostic Inflammatory Index (PNI) will calculated formula "10 × Serum Albumin (g/dL) + (0.005 × Total Lymphocyte Count (/mm³))".	at the beginning of the study
The dietary inflammatory index	The dietary inflammatory index will be calculated from individuals' 24-hour food consumption averages. The dietary inflammatory index will be calculated as a total of 1,000 calories, taking into account the dietary inflammatory load of the foods consumed. In this study, the dietary inflammatory index will be calculated for a total of 27 food items.	3 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Food Consumption Record	The food consumption record will be taken to evaluate the nutritional status of the participants. Food consumption records will be evaluated in the BeBIS (Nutrition Information System) program and the daily energy (kcal) intake will be calculated.	3 days
Food Consumption Record	The food consumption record will be taken to evaluate the nutritional status of the participants. Food consumption records will be evaluated in the BeBIS (Nutrition Information System) program and the daily carbohydrate (g), protein (g), fat (g), saturated fat (g), monounsaturated fatty acid (g), polyunsaturated fatty acid (g), omega-3 fatty acids (g), omega-6 fatty acids (g), and fiber (g) intake will be calculated.	3 days
Food Consumption Record	The food consumption record will be taken to evaluate the nutritional status of the participants. Food consumption records will be evaluated in the BeBIS (Nutrition Information System) program and the daily vitamin E (mg), thiamine (mg), riboflavine (mg), niacin (mg), vitamine B5 (mg), vitamin B6 (mg), vitamin C, sodium (mg), potassium (mg), calcium (mg), magnesium (mg), phosphor (mg), iron (mg), zinc (mg), copper (mg), cholesterol (mg) intake will be calculated.	3 days
Bristol Stool Form Scale	The Bristol Stool Form Scale, developed by Lewis and Heaton in Bristol, England, is a subjective scale used to assess an individual's stool consistency and bowel habits. This scale assesses defecation status in seven groups: Type 1 and Type 2 constipation; Type 3, Type 4, and Type 5 normal defecation; and Type 6 and Type 7 diarrhea. The form will be asked to participants.	at the beginning of the study
Gastrointestinal Symptom Assessment Scale	Developed by Revicki and colleagues and validated for Turkish by Turan et al., the GSRS is used to assess common symptoms of gastrointestinal disorders. The GSRS asks how an individual has felt about gastrointestinal issues over the past week. The scale consists of 15 questions, divided into five subscales: diarrhea (3 questions), dyspepsia (4 questions), constipation (3 questions), abdominal pain (3 questions), and reflux (2 questions). The higher the score, the more severe the gastrointestinal symptoms.	at the beginning of the study

Collaborators and Investigators

• Sponsor: Istanbul Bilgi University
• Investigators: Principal Investigator: Hande Seven Avuk, Ph.D., Istanbul Bilgi University; Principal Investigator: Gökben Anıl, Halic University

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2025
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): July 30, 2026

Study Registration Dates

• First Submitted: December 7, 2025
• First Submitted That Met QC Criteria: December 7, 2025
• First Posted (Actual): December 19, 2025

Study Record Updates

• Last Update Posted (Actual): December 19, 2025
• Last Update Submitted That Met QC Criteria: December 7, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: bariatric surgery; sleeve gastrectomy; systemic inflammation; diatary inflammation
• Other Study ID Numbers: BARINFLAMMATION

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