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Mediterranean Diet and Oxidative Stress in Type 1 Diabetes (MEDOX-T1D)

The Relationship Between Adherence to the Mediterranean Diet and Oxidative Stress in Children With Type 1 Diabetes

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07544368
Acronym
MEDOX-T1D
Enrollment
54
Registered
2026-04-22
Start date
2026-04-01
Completion date
2027-03-01
Last updated
2026-04-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Continuous Glucose Monitoring System, Oxidative Stress, Type 1 Diabetes (Juvenile Onset)

Keywords

Type 1 Diabetes, Mediterranean Diet, Oxidative Stress

Brief summary

Achieving optimal glycemic control in type 1 diabetes requires a holistic approach that includes individualized medical nutrition therapy in addition to appropriate insulin therapy. When diabetes is poorly managed, metabolic control is impaired. Hyperglycemic events increase oxidative stress in the body and can lead to complications. The aim of this study is to examine the effect of a 12-week Mediterranean diet on oxidative stress markers in children with type 1 diabetes who do not meet the metabolic target (HbA1c \> 7%) and whose adherence to the Mediterranean diet is "poor" and "needs improvement". The study, planned between March 2026 and March 2027, will be conducted with girls aged 10-18 years with type 1 diabetes who are followed up at the Department of Pediatric Endocrinology, Istanbul Faculty of Medicine, Istanbul University. In the first phase, participants were divided into groups based on their HbA1c levels: those with HbA1c ≤ 7 met the metabolic target (Group A); Those with HbA1c \> 7 will be divided into two groups: those not meeting the metabolic target (Group B). In the second stage, the intervention group will be determined according to the results of the KIDMED, the pediatric Mediterranean diet adherence scale. Those in Group B who did not meet the metabolic targets and those with "poor" and "need improvement" KIDMED results will form the intervention group (Group C). Adolescents in Group C will receive a 12-week Mediterranean diet intervention. Information will be collected from participants using questionnaires, scales, and experimental methods. This includes completing the 'Personal Information Form', 'Biochemical Parameters Form', '3-Day Nutrition Questionnaire', 'KIDMED scale', and 'Sensor Data Form'. The obtained data will be analyzed both individually and before-and-after using SPSS 26. The findings are expected to show improvement in OS markers in the intervention group. Improvement in glycemic control markers is also predicted. A decrease in HbA1c levels, a reduction in blood sugar fluctuations, and an increase in the duration of staying within the target range are expected. This study is expected to contribute to the literature by revealing the effects of the Mediterranean diet on oxidative stress and metabolic control parameters in type 1 diabetes. It is anticipated that the findings will support the potential role of dietary approaches with antioxidant properties not only in glycemic control but also in oxidative stress levels and long-term complication risks.

Detailed description

Type 1 diabetes is an autoimmune disease that primarily occurs in childhood and is characterized by insufficient insulin secretion due to damage to the beta cells of the pancreas. While the incidence of Type 1 diabetes is increasing, the age of onset is also decreasing. Diabetes management is crucial for maintaining and protecting health. When glycemic control is not achieved, the number of hypoglycemic and hyperglycemic events increases. HbA1c levels rise. This situation results in poor metabolic control. Oxidative stress in the body increases. Oxidative stress can play a role in the pathogenesis of diabetes, and if the disease is not controlled, it leads to the development and rapid progression of complications (retinopathy, nephropathy, neuropathy, etc.). Many studies conducted on diabetic children have shown that their oxidative stress levels are high and antioxidant levels are low compared to healthy controls. Nutrition, the foods we consume, are modifiable determinants of oxidative stress. The antioxidant and polyphenol content of the diet is particularly important. The Mediterranean diet; Foods rich in antioxidants, such as vegetables, fruits, legumes, fish, olive oil, nuts, and fermented foods, have been shown in many studies to have a protective effect. In the first phase of the study, participants will be divided into two groups based on their HbA1c levels: those with HbA1c ≤7 (meeting the metabolic target) (Group A); and those with HbA1c \>7 (not meeting the metabolic target) (Group B). Information will be collected from participants using questionnaires, scales, and experimental methods. This includes completing a Personal Information Form, a Biochemical Parameters Form, a 3-Day Food Intake Record, the KIDMED scale, and a continuous glucose monitoring sensor data form. Disease-specific information will be obtained from patient files, while biochemical data will include routine follow-up measurements such as complete blood count, CRP, CK, HbA1c%, lipid profile (HDL, LDL, total cholesterol, triglycerides), liver function tests (AST, ALT), kidney function tests (BUN, urea, creatinine), TSH, ST4, and vitamin D. Oxidative stress markers FASN, G6PD, GST, GR, and 6-PGD will be measured in venous blood. Blood samples will be taken in the outpatient clinic by a diabetes nurse. Anthropometric measurements will be taken as part of the personal information form. Body weight and height measurements will be taken in the outpatient clinic by a nutritionist (the same person). Height measurements will be taken with a stadiometer with 0.1 cm accuracy, while the patient is in an upright position with the head in the Frankfort plane (the ear canal and the lower boundary of the orbit/eye socket are aligned, and the gaze is parallel to the ground). Body weight measurements will be taken with a scale with 0.1 gram accuracy. Anthropometric data (body mass index, weight, height, and standard deviation scores) will be evaluated according to the standards developed by Neyzi et al. for Turkish children. To ensure accurate food consumption records, the nutritionist will provide training on correctly expressing portion sizes using spoons, bowls, ladles, cups, etc., and the patients will be asked to keep a record using a form for 2 weekdays and 1 weekend. In the evaluation of three-day food consumption, the Nutrition Information System (BEBIS) software package containing food compositions specific to Turkey will be used, and the analysis results will be compared with the dietary reference intakes in the recommendations of the Turkish Nutrition Guide. In the second stage, the intervention group will be determined according to the results of the KIDMED (Mediterranean Diet Quality) scale, which is a pediatric Mediterranean diet adherence scale. The KIDMED scale (Mediterranean Diet Quality) was developed by Serra Majem et al. in 2004. The Turkish validity and reliability study of the scale was conducted by Şahingöz et al. in 2019. The scale consists of 16 questions. The questions are answered with yes (1) and no (2). Items 6, 12, 14, and 16 are scored as -1, and the remaining 12 items are scored as +1. In the evaluation of the scale, ≤ 3 is considered low adherence, 4-7 is considered moderate adherence, and ≥ 8 is considered high adherence. In our study, those in Group B who did not meet metabolic targets, and those with KIDMED results deemed "poor" and "needing improvement," will form the intervention group (Group C). Adolescents in Group C will be scheduled for a 12-week Mediterranean diet intervention. The Mediterranean Diet training is planned as a 30-45 minute face-to-face meeting, and the brochure to be used in the training is available in Appendix 1. Visits will be made by phone between weeks 2-3 and weeks 7-9, and diet compliance will be monitored with dietitian consultations, with additional motivational consultations provided if necessary. A face-to-face meeting will be held in week 12, and anthropometric measurements will be repeated. Three-day food consumption records will be taken. Biochemical data obtained during routine 3-month follow-up will be retrieved from file information. Oxidative stress markers will be repeated. If there are cases in Group A that are poor or needing improvement, these individuals will also receive Mediterranean Diet training, and their follow-up will continue with the dietitian of the department they are being monitored by. Participants in group B who received a 'good' KIDMED score will continue with standard medical nutritional therapy under the guidance of a dietitian.

Interventions

Participants will follow a Mediterranean diet rich in plant-based foods, olive oil as the main fat source, moderate consumption of fish and dairy products, and limited intake of red and processed meats. Dietary adherence will be assessed using food records, and participants will be monitored throughout the study period to ensure compliance.

Sponsors

Istanbul University
Lead SponsorOTHER

Study design

Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
SUPPORTIVE_CARE
Masking
SINGLE (Subject)

Intervention model description

Before-after, prospective

Eligibility

Sex/Gender
FEMALE
Age
10 Years to 18 Years
Healthy volunteers
No

Inclusion criteria

* Ages 10-18 years * BMI between the 5th and 95th percentile (normal to overweight) * Diagnosis of Type 1 Diabetes for ≥1.5 years * Users of a continuous glucose monitoring (CGM) system * No other comorbidities and not taking medications * Non-smokers and non-alcohol users (including e-cigarettes) * Written informed consent provided by the participant and their parent/guardian

Exclusion criteria

* Presence of any acute or chronic disease other than Type 1 Diabetes * Current use of any medications * BMI ≥ 95th percentile (obese) * Presence of an eating disorder * Use of tobacco, e-cigarettes, or alcohol

Design outcomes

Primary

MeasureTime frameDescription
HbA1c12 weeks compared to baselineHbA1c
Mediterranean Diet Quality (KIDMED) Scale12 weeks compared to baselineMediterranean Diet Quality (KIDMED) Score: Accordingly, the scores derived from the checklist are classified into three categories: low adherence (≤3), moderate adherence (4-7), and high adherence (≥8).
6-PGD12 weeks compared to baseline6-phosphogluconate dehydrogenase
GR12 weeks compared to baselineU/L, glutathione reductase
GST12 weeks compared to baselineglutathione S-transferase
G6PD12 weeks compared to baselineglucose-6-phosphate dehydrogenase
FASN12 weeks compared to baselineng/mL, fatty acid synthase

Secondary

MeasureTime frameDescription
Vitamin D12 weeks compared to baselinevitamin D
TSH12 weeks compared to baselineThyroid stimulated hormone
ST412 weeks compared to baselineserum free thyroxine
CRP12 weeks compared to baselinemg/L, C-Reactive Protein
CK12 weeks compared to baselineU/L, Creatine Kinase
Total Cholesterol12 weeks compared to baselineSerum Total Cholesterol
LDL-C12 weeks compared to baselinemg/dl, LDL cholesterol
HDL-C12 weeks compared to baselinemg/dl, HDL cholesterol
Triglycerides12 weeks compared to baselinemg/dL
ALT12 weeks compared to baselineU/L, Alanine Aminotransferase
AST12 weeks compared to baselineU/L, Aspartate Aminotransferase
BUN12 weeks compared to baselinemg/dL, Blood Urea Nitrogen
Creatinine12 weeks compared to baselinemg/dL
Fasting Plasma Glucose12 weeks compared to baselineFPG mg/dl
Weight12 weeks compared to baselineBody weight, kg
Body Mass Index12 weeks compared to baselineBMI kg/m2
Carbohydrate12 weeks compared to baselineCarbohydrate intake, gram
Protein12 weeks compared to baselineProtein intake, gram
Fat12 weeks compared to baselineFat intake, gram
Energy12 weeks compared to baselineEnergy intake, kcal
Dietary Fiber12 weeks compared to baselineDietary Fiber intake, gram
TIR12 weeks compared to baselineTime in Range (%70-180 mg/dL), CGM metric
TAR12 weeks compared to baselineTime Above Range (%181-250), CGM metric
TBR12 weeks compared to baselineTime Below Range (%54-69 mg/dL), CGM metric
CV12 weeks compared to baselineCoefficient of Variation (%), CGM metric
SD12 weeks compared to baselineStandard Deviation (mg/dL), CGM metric
Mean Glucose Levels12 weeks compared to baselinemg/dL, CGM metric
GMI12 weeks compared to baselineGlucose Management Indicator (%), CGM metric
Nighttime TIR12 weeks compared to baselineNighttime Time in Range (%), CGM metric
Dietary Cholesterol12 weeks compared to baselineDietary Cholesterol intake, mg
Vitamin A12 weeks compared to baselineVitamin A intake, µg
Vitamin E12 weeks compared to baselineVitamin E inatke, mg
Vitamin B112 weeks compared to baselineVitamin B1 intake, mg
Vitamin B212 weeks compared to baselineVitamin B2 intake, mg
Vitamin B312 weeks compared to baselineVitamin B3 intake, mg
Vitamin B512 weeks compared to baselineVitami B5 intake, mg
Vitamin B612 weeks compared to baselineVitamin B6 intake, mg
Vitamin B1212 weeks compared to baselineVitamin B12 intake, µg
Folate12 weeks compared to baselineFolate intake, µg
Vitamin C12 weeks compared to baselineVitamin C intake, mg
Calcium12 weeks compared to baselineCalcium İntake, mg
Magnesium12 weeks compared to baselineMagnesium intake,mg
Potassium12 weeks compared to baselinePotassium intake, mg
Phosphorus12 weeks compared to baselinePhosphorus intake, mg
Iron (Fe)12 weeks compared to baselineIron intake, mg
Zinc12 weeks compared to baselineZinc intake, mg
Height12 weeks compared to baselineBody Height, cm

Contacts

CONTACTBeyza Eliuz Tipici
beliuz@istanbul.edu.tr+90 554 624 57 68

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Apr 30, 2026