The prevalence of obesity is one of the main public health problems worldwide, reaching 18% among young people between 5 and 19 years of age in 2016. One possibility of effective treatment can be the Mediterranean diet (MD). Therefore, it is proposed to carry out a nutritional intervention based on this diet to more effectively reduce obesity in adolescents. The main purpose of this multicentre study is to assess whether an energy-restricted Mediterranean-style diet (MD) intervention including healthy products from the Mediterranean basin (mixed nuts, pomegranate and hummus) and sourdough bread is more effective against obesity and associated CVD risk factors than a conventional low-fat diet carrying out a multicentre nutritional and clinical intervention study specifically targeting obese/overweight adolescents (13-17y) from different Mediterranean countries; all combined with an educational web-application designed to encourage healthy behaviours. It is a multicenter, randomized, controlled intervention study conducted with adolescents with obesity/overweight ≥90 percentile who do not suffer from any chronic disease. 240 subjects will be recruited from three Mediterranean countries: Italy (Parma), Portugal (Coimbra) and Spain (Reus), specifically 80 participants per country, 40 adolescents as an intervention group and 40 as a control group, in Reus. The intervention study is scheduled to begin in January 2021. The intervention group will receive a diet based on the characteristics of MD, and will be reinforced with satisfying and healthy Mediterranean foods such as sourdough bread (2 servings of 50-60g / day), squeezed pomegranate (4 servings of 200ml / week), hummus/chickpeas (2 portions of chickpeas of 150-200g / week, one in hummus format) and mixed nuts (4 servings of 30g / week); and the control group will receive a recommended diet based on the consumption of low-fat foods. A caloric restriction of 20% of the total energy requirements will be applied to both groups in adolescents with BMI ≥95 percentile (obesity) and a caloric restriction \<20% of the total energy requirements will be applied in adolescents with BMI ≥90 to \<95th percentile according to overweight (gender/age / physical activity). The diet will be applied for 4 months in both groups. Adolescents from both groups will be given a motivational interview and will be provided with an educational website that will be used during the intervention, through which they will learn.
The principal outcome is BMI z-score, a standardized measure of BMI based on the specific age and gender norms. The effectiveness of the intervention will be evaluated by comparing the BMI z-score between the control (low-fat diet) and intervention (MD) groups. The secondary outcomes are: Adherence to the DM, KidMed questionnaire; Level of physical activity, PAQ-A questionnaire; Habit/food intake: 3-day dietary record, Helena study food frequency questionnaire, Knowledge about food and nutrition, a questionnaire from Helena's study; Quality of life, kid screen-27 Index; Sociodemographic data of the parents; Anthropometric data: weight, height, BMI, body composition, waist circumference, waist-hip ratio; Clinical variables: blood pressure, Biochemical variables and omic determinations: in urine, blood and feces. In total, the adolescents will receive 5 visits: * 1 pre-selection visit (to check inclusion / exclusion criteria in the study) (V0) * 1 inclusion visit (V1) in which stool, urine, and blood samples will be collected, anthropometric measurements (such as weight and waist circumference) and blood pressure will be taken, and questionnaires and records will be answered dietary. * 1 follow-up visit (V2), at 2 months, in which anthropometric and blood pressure measurements will be taken and questionnaires and dietary records will be answered. * 1 final visit (V3), at 4 months, in which stool, urine, and blood samples will be collected, anthropometric and blood pressure measurements will be made, and questionnaires and dietary records will be answered. * 1 post-intervention follow-up visit (V4), 4 months after the end of the intervention, in which anthropometric and blood pressure measurements will be taken and questionnaires and dietary records will be answered.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
240
Intervention will receive a specific diet designed following the characteristics of Mediterranean Diet
Control group will receive a specific diet designed following the characteristics of Low fat Diet.
Eurecat
Reus, Spain
Change from baseline BMI z-score at 4 months and 8 months
The principal outcome is BMI z-score, a standardized measure of BMI based on the specific age and gender norms. The effectiveness of the intervention will be evaluated by comparing the BMI z-score between the control (low-fat diet) and intervention (MD) groups.
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Adherence to the Mediterranean Diet at 4 and 8 months
Change of Adherence to the Mediterranean Diet using KIDMED test by comparing control between the intervention group Scores: =\<3 points: Very low-quality diet 4 to 7 points: Need to improve the eating pattern to fit the model Mediterranean. =\>8 points: Optimal Mediterranean diet
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Level of physical activity at 4 and 8 months
Change of Physical Activity using the Physical Activity Questionnaire test by comparing control between the intervention group A score 1 indicates low physical activity whereas a score of 5 indicates high physical activity
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Habit/food intake at 4 and 8 months
Change of Habit/food intake using 3-day dietary record, Helena study food frequency questionnaire by comparing control between intervention group
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Knowledge about food and nutrition intake at 4 and 8 months
Change of Knowledge about food and nutrition intake using Helena's study knowledge questionnaire by comparing control between intervention group
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Life quality at 4 and 8 months
Change of life quality using kidscreen-27 Index by comparing control between intervention group
Time frame: "4 months" and "4 months after study cessation"
Sociodemographic data of the parents one time frame
Sociodemographic data of the parents will be assessed at baseline of study using Healthy Behaviour in School Age Children. Sociodemographic data will be divided by low, medium or high socioeconomic level.
Time frame: 1 time frame
Change from baseline BMI data at 4 and 8 months
BMI will be assessed by weight (kg) / height (m2), and using Centers for Disease Control and Prevention (CDC) BMI percentiles and will be compared between control and intervention group.
Time frame: "4 months" and "4 months after study cessation"
Change from baseline waist circumference data at 4 and 8 months
Waist circumference (cm) will be evaluated and will be compared between control and intervention group.
Time frame: "4 months" and "4 months after study cessation"
Change from baseline Waist-hip ratio data at 4 and 8 months
Waist-hip ratio will be evaluated by waist and hip circumference and will be compared between control and intervention group.
Time frame: "4 months" and "4 months after study cessation"
Change of Gut-derived metabolites (LPS, SCFAs, lactate, bile acids)
Gut-derived metabolites of both groups will be evaluated by Faeces and/or plasma using NMR /GC-MS
Time frame: 4 months
Change of biomarkers of oxidative stress (8-OHdG, F2-isoprostanes)
Biomarkers of oxidative stres of both groups will be evaluated by urine using ELISA
Time frame: 4 months
Change of biomarkers of inflammation (IL-6, CRP, TNFα, MCP1, IL-8)
Biomarkers of inflammation of both groups will be evaluated by plasma using Magnetic bead-based multiplex assays Homeostatic Model Assessment for insulin resistance
Time frame: 4 months
Change of biomarkers of adipose tissue function (adiponectin, leptin, resistin)
Biomarkers of adipose tissue function of both groups will be evaluated by plasma using Magnetic bead-based multiplex assays Homeostatic Model Assessment for insulin resistance
Time frame: 4 months
Change of Biomarkers of insulin resistance
Biomarkers of insulin resistance of both groups will be evaluated by plasma using Magnetic bead-based multiplex assays Homeostatic Model Assessment for insulin resistance
Time frame: 4 months
Change of biomarkers of cardiovascular risk (TMAO)
Biomarkers of cardiovascular risk of both groups will be evaluated by plasma and urine using UHPLC MS
Time frame: 4 months
Change of circulating levels of glucose and blood lipid profile
Circulating levels of glucose and blood lipid profile of both groups will be evaluated using Enzymatic assays
Time frame: 4 months
Change of Food Intake biomarkers
Food Intake biomarkers of both groups will be evaluated by urine using Metabolomics (UHPLC MS)
Time frame: 4 months
Change of Advanced glycation end products (AGEs) related analyses
Advanced glycation end products will be assessed by plasma or erythrocytes using ELISA / enzymatic assays
Time frame: 4 months
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