Stable Isotope Method to Assess Dietary Protein Quality
Condition: Biological Availability
Study type: Interventional

Summary: 
      The evaluation of protein quality has been identified as the top priority question by the
      Food and Agricultural Organization (FAO) of the United Nations. However, the current
      available methods do not precisely estimate protein quality, or need invasive procedures. The
      proposed 'dual tracer approach' is a non-invasive method to evaluate protein quality in
      humans.

      The present project characterizes the use of 15N-intrinsically-labelled milk protein as a
      reference-protein for development a non-invasive method that can be used to assess protein
      quality in human subjects
    

Detailed description: 
      Rationale: The evaluation of protein quality has been identified as the top priority question
      by the Food and Agricultural Organization (FAO) of the United Nations. However, the current
      available methods do not precisely estimate protein quality, or need invasive procedures. The
      proposed 'dual tracer approach' is a minimal invasive method to evaluate protein quality in
      humans.

      Objective: The present project characterizes the use of 15N-intrinsically-labelled milk
      protein as a reference-protein for development a minimal invasive method that can be used to
      assess protein quality in human subjects. For this purpose, our primary objectives are to
      define the digestive and metabolic behaviour and distribution of the
      15N-intrinsically-labelled milk protein compared to the internal standard 13C-spirulina.

      Study design: Randomized cross-over trial with two experimental meals. Study population:
      Healthy male and female, age 18-35y Intervention (if applicable): On two separate test days,
      subjects will receive a semi liquid meal (pudding) divided in 9 portions, (meal 1: 27 En%
      Protein,10 En% fat, 62 En% carbohydrates; meal 2: 14 En% Protein,10 En% fat, 75 En%
      carbohydrates), with intrinsically labelled 15N protein powder. Furthermore, the meal will
      contain a trace amount of 13C-labelled algae protein as an internal standard. Meals will
      differ in the amount (e.g. 50g or 25g) of 15N-labelled milk protein.

      Main study parameters/endpoints: The ratio of isotopic enrichment (15N/13C) of (total) amino
      acids of the test meal and the blood plasma as determined by (gas chromatography-) isotope
      ratio mass spectrometry ((GC)-IRMS).

      Nature and extent of the burden and risks associated with participation, benefit and group
      relatedness: A meal challenge with intrinsically labelled protein and addition of stable
      isotope tracer is frequently used in postprandial studies. Stable isotopes are naturally
      occurring isotopes and are not harmful for subjects, as there is no decay. Furthermore,
      placing venous catheters and blood sampling can occasionally cause a local haematoma or
      bruise and some participants may report pain or discomfort. Subjects have to come to the
      research facility three times, a screening visit of 1 hour, and 2 experimental days of 7
      hours. Subjects will be financially compensated for participation.
    

Intervention name(s): intrinsically labeled milk protein
Intervention type(s): Dietary Supplement
Intervention MeSH terms: Caseins
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science