The goal of this clinical trial is to evaluate the effect of A2 β-casein-containing milk and dairy product consumption on nutritional status, gastrointestinal symptoms, quality of life, sleep quality, and selected biochemical parameters in adolescents aged 10-18 years with celiac disease. The main questions it aims to answer are: * Does consumption of A2 β-casein-containing milk and dairy products improve gastrointestinal symptoms and quality of life in adolescents with celiac disease? * Does consumption of A2 β-casein-containing milk and dairy products affect nutritional status, body composition, and biochemical parameters compared with standard milk and dairy products? Researchers will compare adolescents consuming A2 β-casein-containing milk and dairy products with adolescents consuming standard milk and dairy products to see if A2 β-casein provides additional benefits. Participants will: * Consume the assigned milk and dairy products during the intervention period. * Attend baseline and follow-up assessments. * Complete dietary records and questionnaires related to gastrointestinal symptoms, sleep quality, and quality of life. * Undergo anthropometric, body composition, hand grip strength, and biochemical assessments.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
50
Participants consumed milk and dairy products containing A2 β-casein during the 8-week intervention period.
Participants consumed standard milk and dairy products during the 8-week intervention period.
Sariyer Hamidiye Etfal Training and Research Hospital
Istanbul, Turkey (Türkiye)
Change From Baseline in Celiac Disease-Specific Quality of Life Total Score at Week 8
Celiac disease-specific quality of life will be assessed using the Celiac Disease Dutch Questionnaire (CDDUX). The total score ranges from 0 to 100, with higher scores indicating better quality of life.
Time frame: Baseline and Week 8
Change From Baseline in Celiac Symptom Index Total Score at Week 8
Gastrointestinal symptoms will be assessed using the Celiac Symptom Index (CSI). The CSI total score ranges from 16 to 80, with higher scores indicating more severe celiac disease-related symptoms.
Time frame: Baseline and 8 weeks
Change From Baseline in Anti-tTG IgA Level at Week 8
Serum anti-tissue transglutaminase immunoglobulin A (anti-tTG IgA) level will be measured and reported as RU/mL to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Anti-tTG IgG Level at Week 8
Serum anti-tissue transglutaminase immunoglobulin G (anti-tTG IgG) level will be measured and reported as RU/mL to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Leukocyte Count at Week 8
Leukocyte count will be measured in blood samples and reported as 10⁹/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Neutrophil Count at Week 8
Absolute neutrophil count will be measured in blood samples and reported as 10⁹/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Neutrophil-to-Lymphocyte Ratio at Week 8
The neutrophil-to-lymphocyte ratio (NLR) will be calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. NLR will be reported as a unitless ratio to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Albumin Level at Week 8
Serum albumin level will be measured and reported as g/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Total Protein Level at Week 8
Serum total protein level will be measured and reported as g/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Alanine Aminotransferase Level at Week 8
Serum alanine aminotransferase (ALT) level will be measured and reported as U/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Aspartate Aminotransferase Level at Week 8
Serum aspartate aminotransferase (AST) level will be measured and reported as U/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Ferritin Level at Week 8
Serum ferritin level will be measured and reported as µg/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Folate Level at Week 8
Serum folate level will be measured and reported as µg/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Vitamin B12 Level at Week 8
Serum vitamin B12 level will be measured and reported as ng/L to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Serum Calcium Level at Week 8
Serum calcium level will be measured and reported as mg/dL to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Body Weight at Week 8
Body weight will be measured and reported in kilograms (kg) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Height at Week 8
Height will be measured and reported in centimeters (cm) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Body Mass Index at Week 8
Body mass index (BMI) will be calculated by dividing body weight in kilograms by height in meters squared and reported as kg/m² to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in BMI-for-Age Z Score at Week 8
BMI-for-age Z score will be calculated using the World Health Organization 2007 growth reference for children and adolescents aged 5-19 years to assess the change from baseline to Week 8. A score of 0 represents the median of the reference population.
Time frame: Baseline and Week 8
Change From Baseline in Height-for-Age Z Score at Week 8
Height-for-age Z score will be calculated using the World Health Organization 2007 growth reference for children and adolescents aged 5-19 years to assess the change from baseline to Week 8. A score of 0 represents the median of the reference population.
Time frame: Baseline and Week 8
Change From Baseline in Mid-Upper Arm Circumference at Week 8
Mid-upper arm circumference (MUAC) will be measured and reported in centimeters (cm) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change in Sleep Quality Assessed by the Pittsburgh Sleep Quality Index (PSQI)
Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The PSQI total score ranges from 0 to 21, with higher scores indicating poorer sleep quality.
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Time frame: Baseline and Week 8
Change in Hand Grip Strength Measured Using a TAKEI TKK-5401 Hand Dynamometer
Hand grip strength (kg) will be measured using a TAKEI TKK-5401 hand dynamometer.
Time frame: Baseline and Week 8
Change in Stool Form Assessed by the Bristol Stool Form Scale (BSFS)
Stool form will be assessed using the Bristol Stool Form Scale (BSFS). The scale classifies stool form into seven types (Types 1-7), with Types 1-2 indicating constipation, Types 3-4 indicating normal stool form, and Types 5-7 indicating loose stools or diarrhea.
Time frame: Baseline and Week 8
Change From Baseline in Trunk Fat Percentage at Week 8
Trunk fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Total Body Fat Percentage at Week 8
Total body fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Right Arm Fat Percentage at Week 8
Right arm fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Left Arm Fat Percentage at Week 8
Left arm fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Right Leg Fat Percentage at Week 8
Right leg fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Left Leg Fat Percentage at Week 8
Left leg fat percentage will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported as a percentage (%) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Body Fat Mass at Week 8
Body fat mass will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported in grams (g) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8
Change From Baseline in Fat-Free Mass at Week 8
Fat-free mass will be assessed using bioelectrical impedance analysis (Tanita BC-601) and reported in grams (g) to assess the change from baseline to Week 8.
Time frame: Baseline and Week 8