The Dose Response of Calcium Co-ingested With Protein on GLP-1 Concentrations
Condition: GLP-1 Concentration
Study type: Interventional

Summary: 
      Hormones that are produced by our stomach and intestines play a role in regulating our
      appetite and health. One of the most important hormones is called GLP-1. The food we eat
      influences the release of this hormone and evidence suggests that protein and calcium are key
      nutrients that stimulate the secretion of GLP-1. We want to know if there is a dose related
      response by increasing the amount of calcium ingested with a constant amount of protein on
      the release of this hormone. We hypothesise that with increasing calcium dose we will see an
      increase in GLP-1 concentrations in a curvilinear pattern. This may have benefits for
      prescribing an optimal dose of calcium for weight maintenance and health.
    

Detailed description: 
      Recent work at the University of Bath has shown that when ingested with 50 g whey protein
      hydrolysate, Capolac® (milk minerals high in calcium) potently stimulates availability of the
      important hormone glucagon-like peptide-1 (GLP-1). However, it is currently unknown as to
      whether there is a dose dependent response to calcium co-ingestion with protein. Therefore we
      aim to perform a study on the effect of co-ingesting different doses of Capolac® with 25 g
      whey protein hydrolysate on GLP-1 availability. This project will help identify the calcium
      dose required with a moderate amount of protein to optimise GLP-1 availability and also
      provide insight into whether this may affect food intake and appetite.

      Twenty metabolically healthy men and women, age 18-65 years, BMI between 25 and 34.9 kg/m2
      will be recruited to participate in a randomised crossover study. Each participant will
      undergo 4 trials. Each trial will last ~4 hours and will be separated by a minimum of 48h:

        1. CONTROL - 25 g whey protein hydrolysate (227 mg of total calcium ingested)

        2. DOSE 1 - 25 g whey protein hydrolysate + 3179 mg Capolac (984 mg of total calcium
           ingested)

        3. DOSE 2 - 25 g whey protein hydrolysate + 6363 mg Capolac (1742 mg of total calcium
           ingested)

        4. DOSE 3 - 25 g whey protein hydrolysate + 9547 mg Capolac (2500 mg of total calcium
           ingested) Each of these drinks will also contain 500 mL of water and low calorie
           sweetener (80 mg sucralose).

      Participants will be asked to arrive to the laboratory between 08:00 and 9:00 am after not
      eating for between 10-14 hours i.e. in a fasted state (water intake is permitted and
      encouraged). Upon arrival at the laboratory a trained phlebotomist staff member will insert a
      cannula (a small plastic tube) into a vein in the back of the hand. Participants will then be
      given one of the four test drinks, which once ingested will initiate the trial. Just after
      the ingestion of the test drink we will ask you to fill out a palatability scale.

      Blood samples will be taken at baseline, and at 15, 30, 45, 60, 90, 120 and 180 minutes after
      ingestion of the test drink. An appetite questionnaire will also be completed at baseline and
      every 60 minutes after ingestion of the test drink to assess appetite sensations. After the
      180-minute time point participants will be asked to consume a lunch meal until they are
      comfortably full. Once satisfied with the lunch meal they will fill out the final appetite
      questionnaire. The trial day will then be complete. Following study completion participants
      will be asked to complete a restrained eating questionnaire.
    

Intervention name(s): Dose response of Capolac®
Intervention type(s): Dietary Supplement
Intervention description(s): Capolac® (milk minerals high in calcium) dose is manipulated
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: There are 4 conditions where participants will ingest differing amounts of calcium in a randomised order
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science