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.
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).
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
120
Time of 6 week, the last 6 days are standardized
Time of 6 weeks; the first and the last 6 days are standardized
German Institute of Human Nutrition
Potsdam-Rehbruecke, Nuthetal, Germany
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)
Time frame: 6,7,12 weeks
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
Time frame: 6, 7, 12 weeks
Expression of inflammatory markers in blood and fat tissue
Measurement of gene expression of inflammation cytokines and clock genes
Time frame: 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
Time frame: 6,7,12 weeks
Changes in vessel wall thickness of the carotid artery
Vascular ultrasound
Time frame: 6,7,12 weeks
Measurement of activity
each over 6 days measurement: activity protocol, pedometer and activity clock
Time frame: in the 6th, 7th, 12th week
Detection of the gastric emptying time
Time frame: 6,7,12 weeks
Assessment of cognitive performance
Time frame: 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
Time frame: 6, 7, 12 weeks
Epigenetic modification of DNA
Change in adipose tissue DNA methylation pattern
Time frame: 6,7,12 weeks
Biometric data
Nutritional impact of the blood pressure, weight, body mass index, waist-hip ratio
Time frame: 6,7,12 weeks
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