Protein Intake and Satiety: a Postprandial Study
Condition: Satiety
Study type: Interventional

Summary: 
      Obesity is considered the emerging epidemic of the 21st century, becoming one of the major
      public health problems. Excessive body weight increases morbidity and mortality risk, while
      decreases the quality of life and expectance. The prevalence of obesity almost has doubled in
      the last 20 years. According to the World Health Organization, 39% of the population is
      overweight and 13% of the population is obese.

      Obesity is a multifactorial origin disease, where genetic plays an important role. However,
      lifestyle factors, such as unhealthy diets and physical inactivity are the main cause for the
      development of obesity and associated comorbidities such as hypertension, dyslipidemia,
      diabetes and even some types of cancer. The prevention and control of obesity as well as its
      comorbidities requires interventions at individual and population level.

      Intervention studies based on hypocaloric diets show poor adherence in the long term.
      Moreover, high energy density diets accompanied by snacking between meals contribute to
      weight gain. Therefore, the inclusion of bioactive compounds with satiating capacity within
      healthy and personalized dietary patterns could be a strategy to improve adherence in a
      dietary plan, and consequently reduce morbidity and mortality rates associated to obesity.

      Considering this background, the general aim of this investigation is to perform an acute
      postprandial study to evaluate the effect of a dietary protein intake on the feeling of
      hunger and satiety. To carry out this objective, different data will be analysed, such as the
      measurement of gut hormone circulating concentrations, lipid and glucose profile, energy
      compensation after the postprandial period and the total energy intake during the day.
    

Detailed description: 
      This study is designed as a crossover, randomized, three-arm postprandial study. All
      participants attend the Nutrition Intervention Unit of the Centre for Nutrition Research in
      the University of Navarra three times separated by at least one week. The day before each
      study day, participants should avoid vigorous physical exercise, alcohol consumption or
      high-fiber food consumption. Moreover, they are asked to follow a standardized dinner before
      9 pm.

      On each study day, participants visit the Nutrition Intervention Unit in fasting state. After
      5 minutes rest and having answered the first hunger / satiety visual analogue scale (VAS)
      questionnaire, blood pressure is measured. After that, participant are asked to collect a
      baseline urine sample.

      Once the cannulation is placed, first blood collection is performed in fasting state (time
      0). Then, the participant is provided with the randomly assigned standardized breakfast (250
      g of custard) with the addition of 20 g of experimental protein or 20 g of casein or 20 g of
      water. After custard consumption, volunteer is asked to drink 50 mL of water.

      When participant finishes the breakfast, the time is registered and every 15 minutes the
      participant have to complete a VAS questionnaire (15´, 30´, 45´, 60´, 75´ and 90´). Moreover,
      blood samples are drawn at different time points after breakfast intake (15´, 30´, 60´ and
      90´). The cannula is removed when the last blood sample is collected. In addition,
      participants are asked to collect the urine sample at 90 minutes postingestion and to fill a
      questionnaire about gastrointestinal symptoms.

      Finally, participant is offered an ad libitum lunch (ham and cheese sandwiches) to eat until
      feeling comfortably satiated. Once completed, participant leaves the Centre for Nutrition
      Research with the necessary material to register the food intake (solids and liquids) during
      the rest of the day. Likewise, the participant is provided with the questionnaire of
      gastrointestinal symptoms to be filled before the dinner of the same day.
    

Intervention name(s): Experimental dietary protein; Casein; Water
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Breakfast intake consisted on a 250 g custard intake mixed with 20 g of the experimental protein accompanied by a glass with 50 mL water.; Breakfast intake consisted on a 250 g custard intake mixed with 20 g of casein accompanied by a glass with 50 mL water.; Breakfast intake consisted on a 250 g custard intake mixed with 20 g of water accompanied by a glass with 50 mL water.
Intervention MeSH terms: Caseins
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Satiety; Hunger; Obesity; Ghrelin; Visual Analogue Scale; Gastrointestinal hormones; Energy compensation