Red Raspberries on Insulin Action and Oxidative Stress
Condition: Insulin Resistant
Study type: Interventional

Summary: 
      The purpose of this study is to investigate the relative bioavailability and
      absorption/kinetic profile of red raspberry polyphenols consumed with a meal and further to
      determine the relationship of these findings on meal-associated metabolic- oxidative- and
      inflammatory- responses in relatively insulin sensitive and insulin resistant individuals.
    

Detailed description: 
      The proposed study is a randomized, 3-arm, diet-controlled, cross-over study using a
      multi-sampling postprandial paradigm to evaluate the relative bioavailability and
      absorption/kinetic profile of red raspberry polyphenols consumed with a typical American
      breakfast meal and further to determine the relationship of these findings on meal-associated
      metabolic- oxidative- and inflammatory- responses in relatively insulin sensitive and insulin
      resistant individuals. A planned sample size of 24 will be recruited into the study. This
      study will require one initial screening visit, 1 pre-study visit, and 3 study visits. This
      study will take 4-6 weeks per subject to complete.

      The trial will initiate with a screening visit, which will last for about 1-1.5 hours and
      include measuring subjects' height, weight, waist circumference, fasting blood glucose,
      insulin sensitivity, body temperature, blood pressure and heart rate as well as collecting
      general eating, health and exercise habits via questionnaire.

      If willing and eligible to participate, a 3-day food record (2 weekdays and 1 weekend) will
      be given to be completed over the following week to assess subject's baseline dietary intake
      patterns. Information will be used to help subjects adopt a relatively low polyphenolic diet
      over the course of the study. Prior to each postprandial study visit, a dinner meal will be
      provided the day before the study visit to help control for visit to visit variability in due
      to differences in meals the night before the study visit.

      Subjects will arrive at the center in a fasting state for at least 10 hours, well hydrated
      and rested (with normal sleep). Each study visit will require blood draws throughout the
      visit. After evaluation of subject's health status (via anthropometric, vital sign and blood
      glucose measurements and in-person interview), a qualified health professional will place a
      catheter in subject's arm for the purpose of multiple blood sample collections and take the
      initial blood draw in the fasting state. Each subject will be randomized to receive 1 of 3
      meal treatments: Control meal (0 g red raspberry), red raspberry meal 1 [~125 g fresh weight
      (1 cup equivalent)] or red raspberry meal 2 [~250 g fresh weight (2 cup equivalent)], based
      on randomization sequence on 3 Study Day Visits. At each Study visit, after the first blood
      draw (0 h), subjects will be served with the standard breakfast meal (a moderate to high
      fat/carbohydrate) along with fruit variable based on the order randomly selected by computer
      generated sequence. From this point forward, blood collection will occur at the following
      time points: 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 6.5 h, 7 h, 8 h and 24 h to test for
      polyphenol metabolites and other metabolic markers. After the 6h blood draw, a standardized
      lunch meal (polyphenol free) will be provided to subjects. After the 8 h blood draw, the
      catheter will be removed from subjects arm. Subject will be provided with a dinner meal (low
      polyphenol) to take home and asked not to consume anything else other than the provided
      dinner meal except plain water. Subject will be scheduled to come back the next morning for
      the 24 h blood sample collection.
    

Intervention name(s): Red raspberry meal 1; Red raspberry meal 2; Control meal
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): ~125 g fresh weight (1 cup equivalent); ~250 g fresh weight (2 cup equivalent); 0 g red raspberry
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Other
Keywords: insulin sensitive; insulin resistant; red raspberry; polyphenols; bioavailability