NUtriGenomic Analysis in Twins

Study Overview
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Brief Summary
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This is an intervention study in healthy adult twins with the aim to investigate the genetic determination of metabolic responses towards an isocaloric high carbohydrate, low fat diet versus an isocaloric low carbohydrate, high fat diet.

Detailed Description
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The impact of carbohydrates, proteins and fatty acids as major components of daily nutrition on the development of metabolic illnesses is an objective of numerous clinical studies. However, the effect of an isocaloric diet on metabolism is less investigated and not well understood. This study aims to reveal genetic determinated metabolic responses to an isocaloric high carbohydrate, low fat diet versus an isocaloric low carbohydrate, high fat diet in healthy twins. This study generates information for further detailed nutrigenomic analysis. Twins receive an isocaloric diet rich in carbohydrates (55% carbohydrates, 15% protein, 30% fat) with dietary counselling for 5 weeks and afterwards with nutrients supplied for 6 days, followed by an isocaloric diet rich in saturated fat (40% carbohydrates, 15% protein, 45% fat) for 6 days with nutrients supplied and for 4 weeks with dietary counselling and again followed by another 6 days when nutrients were supplied. Anthropometry, blood tests and energy expenditure are performed after the period of diet rich in carbohydrates (Carb), after the first 6 days (HFshort) and at the end of the period of diet rich in fat (HFlong).

Official Title
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Genetic Determinants of Metabolic Responses to Isocaloric Carbohydrate and Fat Diet Strategies

Conditions
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Metabolic Response to Dietary Modification

Intervention / Treatment
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* Other: Isocaloric high carbohydrate diet intervention
* Other: Isocaloric high fat diet intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy twins BMI 18,5-35kg/m² BMI difference < 3kg/m² within the pair of twins Stable weight during the last 3 months Willingness to comply with the assigned diets over the study period Exclusion Criteria: Consumptive diseases Intake of metabolic influence a/o anticoagulent drugs (e.g. cortisone, ASS, antibiotics) Diabetes type 1 and type 2 Pregnancy Chronic disease of heart, kidney, liver High grade anaemia High grade infection disease Relevant change of body weight(+/- 2kg)during isoenergetic 12-weeks of dietary intervention Missing data about primary outcome measures (IVGTT, MTT, data about dietary intake from food diaries or food protocols) Significant deviation from dietary targets during the monitored 12 weeks isoenergetic period Allergies including food allergies

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Diet interventions<br>Sequential dietary intervention | Other: Isocaloric high carbohydrate diet intervention<br>* Time of 6 week, the last 6 days are standardized<br>Other: Isocaloric high fat diet intervention<br>* Time of 6 weeks; the first and the last 6 days are standardized<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genetic variance of change in insulin secretion and sensitivity after sequential diets | change in insulin secretion and sensitivity measured with an intravenous glucose tolerance test (IVGTT) | 6,7,12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variance of insulin sensitivity after the sequential diets | change in insulin sensitivity measured with a meal tolerance test (MTT) allowing for the response of the intestinal hormones | 6, 7, 12 weeks | 
| Expression of inflammatory markers in blood and fat tissue | Measurement of gene expression of inflammation cytokines and clock genes | 6,7,12 weeks | 
| Development of indices for the prediction of fat mass | Change of fat fraction in liver, abdominal and in the total body fat measuring by MRI/H1-spectroscopy, DEXA | 6,7,12 weeks | 
| Changes in vessel wall thickness of the carotid artery | Vascular ultrasound | 6,7,12 weeks | 
| Measurement of activity | each over 6 days measurement: activity protocol, pedometer and activity clock | in the 6th, 7th, 12th week | 
| Detection of the gastric emptying time |  | 6,7,12 weeks | 
| Assessment of cognitive performance |  | 0,5,11 weeks | 
| Nutritional and genetic influence on the circadian rhythm | measurement of hormones in saliva and urine and of circadian gene expression in monocytes and PBMCs | 6, 7, 12 weeks | 
| Epigenetic modification of DNA | Change in adipose tissue DNA methylation pattern | 6,7,12 weeks | 
| Biometric data | Nutritional impact of the blood pressure, weight, body mass index, waist-hip ratio | 6,7,12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Twins, High carbohydrat diet, High fat diet, Isocaloric, Nutrigenomics