Water and Coffee Intervention in Humans
Condition: Excess Intake of Macronutrients; Excess Intake of Micronutrients; Vasopressin Low
Study type: Interventional

Summary: 
      39 healthy subjects without medication (except oral contraceptives) aged 20-70 years are
      recruited via advertisements or through telephone contacts with individuals that had
      previously participated in population-based cohort studies in Malmö. All subjects are exposed
      to three different intervention procedures; water and coffee loads (acutely and chronically),
      or no change from usual fluid intake (as a time-control), respectively in randomized order.
      The daily intake of coffee or water will amount to 3 L of water and 1 L of coffee,
      respectively for one week each. The three interventions (water, coffee and control), are
      separated by three weeks of normal fluid intake as a wash-out period.

      By testing if simple life style interventions, i.e., increased water or coffee intake, may
      affect vasopressin secretion, evaluated as copeptin, we will increase the knowledge as to
      whether such life style induced changes of copeptin may in turn lead to effects on glucose
      tolerance as well as on other cardiometabolic risk factors previously shown to be associated
      with high copeptin level. Thus, the study will lead to further understanding about
      vasopressin and copeptin release and how life style manipulation of the vasopressin system
      may influence glucose metabolism and other cardiometabolic risk factors in healthy
      individuals.
    

Detailed description: 
      Day 1: The initial examination consists of medical history, clinical examination including
      office blood pressure, and blood sampling (overnight fasting plasma copeptin (a marker of
      vasopressin), osmolality, insulin, glucagon, glucose, creatinine, hsCRP and OGTT), and start
      of 24-h urine collection and 24-h ambulatory blood pressure measurement.

      Day 2: After completion of the 24-h urine collection and ABPM, in the fasting state in the
      morning, office blood pressure will be measured and blood sampling for plasma copeptin,
      osmolality insulin, glucagon, glucose, creatinine and hsCRP measurement will be performed.
      Then, during a maximum time period of 20 minutes, subjects will ingest either 1L of water or
      4 dL of coffee, or just 10 ml of water (time control). To map the acute coffee or water
      effect on copeptin, the experiment proceeds with repeated blood sampling every 30 minutes for
      4 hours after the first coffee or water intake. Day 1 then continues with the rest of the
      daily intake, i.e., 2 L of water or 6 dL of coffee in addition to normal food and fluid
      intakes.

      Day 3 to 7: 3 L water per day or 1 L of coffee per day are ingested (or nothing, in the
      control intervention) in addition to each subject's own food and fluid intake. On days 4 and
      6, blood sampling for electrolyte and urea measurement and osmolality will be carried out for
      reasons of safety and compliance check.

      Day 8: Fasting in the morning, office blood pressure, blood sampling (copeptin, osmolality,
      insulin, glucagon, glucose, creatinine, hsCRP) will be performed and a 24-h urine collection
      and ABPM will be started.

      Day 9: The final examination will consist of clinical examination including office blood
      pressure and blood sampling (overnight fasting plasma copeptin, osmolality, insulin,
      glucagon, glucose, creatinine, hsCRP and OGTT), and end of 24-h urine collection and ABPM.
    

Intervention name(s): Water; Coffee; Control
Intervention type(s): Other; Other; Other
Intervention description(s): Please see the associated arm description; Please see the associated arm description; Please see the associated arm description
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: All subjects will be exposed to three different intervention procedures; water and coffee loads (acutely and chronically), or no change from usual fluid intake (as a time-control), respectively in randomized order. The daily intake of coffee or water will amount to 3 L of water and 1 L of coffee, respectively for one week each. 3 weeks of wash-out between each intervention week.
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: copeptin, water, coffee