The RepEAT Study: Individual Differences in Postprandial Glucose Responses and the Relation With Diet and Phenotype
Condition: Postprandial Glucose Responses; Glucose Metabolism
Study type: Interventional

Summary: 
      Postprandial glucose responses are related to an increased risk of developing cardiometabolic
      diseases. Existing research recognizes the presence of inter-individual variation in
      postprandial glucose responses to the same meal or food product. However, the role of diet
      and phenotype in postprandial glucose responses is unclear.

      The primary objective of this study is to determine the variation in postprandial glucose
      responses to the same meals/food products and how this relates to the variation in
      postprandial glucose responses over a 9-week fully controlled dietary intervention within and
      between individuals. Our secondary objectives are to investigate the difference between
      postprandial glucose responses to original products and postprandial glucose responses to
      reformulated products, and to examine the relation between postprandial glucose responses and
      short-term well-being. In addition, we aim to study the relation between variation in
      postprandial glucose and phenotype, including immune function, cognitive performance, and
      microbiota composition.

      63 apparently healthy men and women with a BMI of 25-40 kg/m2, aged 45-75 years will be
      included in the study, comprising a characterization period of 3 weeks and a completely
      controlled dietary intervention of 9 weeks. During these 9 weeks, glucose will be
      continuously monitored to measure postprandial glucose responses to standard foods/meals.

      There are minor risks for the research subjects of this study. Research subjects will invest
      approximately 85 hours in the study. During the characterization week, subjects will visit
      the Wageningen University 3 times and Hospital Gelderse Vallei (Ede, The Netherlands) once.
      During the controlled dietary intervention, subjects will visit the Wageningen University 2-3
      times a week.
    

Detailed description: 
      Postprandial glucose responses are related to an increased risk of developing cardiometabolic
      diseases. Existing research recognizes the presence of inter-individual variation in
      postprandial glucose responses to the same meal or food product. However, the role of diet,
      i.e. the other consumed food products and meals, and phenotype in postprandial glucose
      responses is unclear. A repetitive design and a standardized diet are necessary to determine
      the variation in postprandial glucose responses to a meal or food product irrespective of the
      diet.

      The primary objective of this study is to determine the variation in postprandial glucose
      responses to the same meals/food products and how this relates to the variation in
      postprandial glucose responses over a 9-week fully controlled dietary intervention within and
      between individuals. Our secondary objectives are to investigate the difference between
      postprandial glucose responses to original products and postprandial glucose responses to
      reformulated products, and to examine the relation between postprandial glucose responses and
      short-term well-being. In addition, we aim to study the relation between variation in
      postprandial glucose and phenotype, including immune function, cognitive performance, and
      microbiota composition.

      The study population consists of 63 apparently healthy men and women with a BMI of 25-40
      kg/m2, aged 45-75 years, and who are weight stable (± <3 kg) for at least three months prior
      to inclusion.

      The study comprises a characterization period of three weeks, followed by a fully controlled
      dietary intervention trial of nine weeks. In the characterization period, the phenotype of
      participants will be determined by measures on anthropometrics, immune function, oxidative
      stress, advanced glycation end-products, cognitive performance, microbiota and gut health,
      amylase, genetics, and circulating metabolites. The dietary intervention consists of three
      repetitive rounds of three weeks, in which we test food products in a cross-over setting.
      Participants will consume test products that fall in the same food category, but differ in
      glycaemic index/carbohydrate content. Part of these products is provided by industrial
      partners, of which the original products are reformulated to be reduced in glycaemic
      index/carbohydrate content. During the 9-week dietary intervention all foods are provided,
      giving us a complete and detailed picture of food and nutrient intake during this period. The
      standardized diet follows the average consumption pattern of the study population. Throughout
      the intervention, interstitial glucose concentrations will be measured using continuous
      glucose monitoring (CGM) and physical activity will be monitored with an accelerometer.

      This study is related to a broad general population. There are minor risks for the research
      subjects of this study. Placing a continuous glucose sensor generally does not cause pain,
      but could result in the loss of a drop of blood, or slight skin irritation after wearing.
      Blood sampling will be performed via a cannula or venapunction and the insertion can be a bit
      painful and may cause a bruise. During the characterization period, in total 215 mL of blood
      will be collected in a 3-week timespan. In the following 9 weeks 108 mL, and at the end of
      the intervention 34 mL blood will be collected. Research subjects will invest approximately
      85 hours in the study. During the characterization week, subjects will visit the Wageningen
      University 3 times and Hospital Gelderse Vallei (Ede, The Netherlands) once. During the
      controlled dietary intervention, subjects will visit the Wageningen University 2-3 times a
      week.
    

Intervention name(s): Standardized diet
Intervention type(s): Other
Intervention description(s): During 9 weeks all food products will be standardized and provided by the Research Unit. The standardized diet is based on the average food composition in the Netherlands.
Other intervention name(s): 9-week fully controlled dietary intervention
Intervention model: Single Group Assignment
Intervention model description: Investigational products will be provided in a standardized environment.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Postprandial; Glucose; Standardized diet; Continuous monitoring