Core Services: Human Phenotyping: Dietary Analysis through Metabolomics (MEAL)

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Dietary assessment through metabolomics (IRB# HUM00110543)

Background: Current methods of determining dietary intake (what someone has eaten) rely heavily upon memory and an individual’s willingness and ability to correctly record all food. These methods are highly subject to recall error, require subjective entry of related information and are often time intensive, hence expensive. A potential new method called metabolomics, which identifies small molecules within the blood, may be able to determine dietary intake from a blood sample, and therefore provide an objective method of dietary assessment.

Purpose: Current methods of determining dietary intake (what someone has eaten) rely heavily upon memory and an individual’s willingness and ability to correctly record all food. These methods are highly subject to recall error, require subjective entry of related information and are often time intensive, hence expensive. A potential new method called metabolomics, which identifies small molecules within the blood, may be able to determine dietary intake from a blood sample, and therefore provide an objective method of dietary assessment.

Eligibility: Healthy men and women can participate in this study. Study participants must not be taking medication that affects metabolism. Healthy men and women participating in this study must be…

  • 18 – 45 years of age at the start of the study
  • BMI 18.5-27 kg·m-2
  • Willing to eat only provided meals for the 24 days of the study.
  • Free from cardiovascular, metabolic disease, and diabetes
  • Non-smoker for at least 6 months
  • Weight stable for at least 6 months (gain/loss of up to 5 pounds acceptable)

Study protocol: This study lasts 24 days and consists of three consecutive components. All assessments and food pick-up will occur in the Michigan Clinical Research Unit (MCRU) Suite, located in the lower level of the Cardiovascular Center at the University of Michigan.

Prior to every blood draw, you must fast from 10pm the previous evening until the blood draw. This is to ensure that accurate results are obtained. Fasting means nothing to eat or drink other than water. All blood draws will be scheduled in the morning.

  1. Baseline Assessments:  These assessments will take about 2 hours to complete.
    • We will measure your height and weight. 
    • A small amount (4 teaspoons) of blood will be taken from a vein in your arm.  This will be used to establish your baseline (i.e. typical/normal) metabolite levels.  This will also be used to assess your genes (DNA) and to determine if there is a relationship between your genes and the food that you eat. 
    • Your body composition will be measured via dual energy X-ray absorptiometry (DXA).  This involves lying down on a table while a full-body scan is taken.  This painless procedure usually takes around 10 minutes.
    • We are interested in the types of foods you usually eat. 
      • Dietary recall:  A team member will ask you questions about your food intake in the previous 24 hours.  This will occur in-person or on the phone and will last about 20-30 minutes. 
      • Food frequency questionnaire:  You will complete a survey that assesses the types of foods you typically eat.  This survey takes around 20 minutes.
    • Pending your schedule, you will be given food for the next three days (standard diet).
  2. Standard Diet:  For three days, all study participants will be provided the same diet.  This diet will be composed of 15% protein, 35% fat and 50% carbohydrates and was chosen because it matches the ‘typical’ American diet.  You will be given the amount of food you need to maintain body weight. 
    • The morning after you have completed this diet, you will return to MCRU for about 30 minutes. 
      • A small amount of blood (2 teaspoons) will be drawn from a vein in your arm. 
      • Your body weight will be measured.
      • You will pick-up food for the next few days.
    • Dietary recall:  1x during standard diet
  3. Experimental Diet:  You will be randomly assigned to consume either a high carbohydrate or a high fat diet for 21 days.  You have an equal chance of being assigned to either group.  These diets were chosen because they are distinct from each other and will influence blood metabolites in very different ways – i.e. if our hypothesis is correct, we should be able to determine which diet you ate based upon the metabolites in your blood. 
    • Diets:  The high fat diet is composed of 15% protein, and 60% fat, 25% carbohydrates.  The high carbohydrate diet is composed of 15% protein, and 10% fat, 75% carbohydrates.  The fat portion for both diets will be composed of 50% saturated fats and 50% unsaturated fats. 
    • You will return to MCRU 4x for blood draws. 
      • A small amount (2 teaspoons) of blood will be drawn from a vein in your arm at each visit. 
      • Your weight will also be measured at this time. 
      • Each visit will last about 30 minutes. 
    • You will return to MCRU to pick-up prepared food every 2-3 days. 
      • Your weight will be measured each time you come to MCRU.
      • You will pick-up food after blood draws and will also come to MCRU a few other times for this purpose.  The exact number of times will vary based upon your schedule. 
    • Dietary recall:  3x during the experimental diet

    All participants will maintain body weight during this study:  Every time you come to MCRU your body weight will be measured.  If you gain or lose a significant amount of weight (≥5 pounds), the amount of food you are given will be adjusted so that your body weight returns to baseline. 

    All meals and snacks will be provided to you.

  • You will be expected to eat everything that is provided and only what is provided.  You will be asked to return all containers and any uneaten food to the study team. 
  • You may consume water and non-caloric beverages of your choice (i.e. coffee, tea, diet drinks).  If you would like milk/creamer/sugar/etc. for your coffee or tea, alert the study team ahead of time and we will include these in the foods we provide. 
  • You may not consume alcohol during this study. 

Total blood volume:  20mL (4 teaspoons) of blood will be collected during baseline assessments, 10mL (2 teaspoons) will be collected during the standard diet, and 40mL (2 2/3 tablespoons) will be collected during the experimental diet (4 blood draws x 2 teaspoons each). If you complete the entire study, 70mL (4 2/3 tablespoons) of blood will be collected.  The amount of blood collected during this 24-day study is far less than the amount of blood given during a typical blood donation. 

A portion of these samples may be stored for future analysis. The label on these stored samples will not have any personal identification and they will not be able to be linked to you.

How much of my time will be needed to take part in this study?  The entire study will take 24 days.  This will involve 6 MCRU visits.  The baseline visit will last approximately 2 hours, with subsequent visits lasting approximately 15 or 30 minutes.  Pickup of food with a blood draw (5x) should take 30 minutes.  Pickup of food only (5x) should take 15 minutes.  Each subject will also be asked to do 5 dietary recalls, one on the first visit and the next 4 over the phone.  These will take approximately 30 minutes each.  The entire study will be completed in 24 days.

When will my participation in the study be over?  The study will be completed within 24 days.

Compensation:  You will be compensated $35 after completing baseline assessments and the standard diet, and $135 after completing the experimental diet ($200 total).

Contact:  To sign-up for this study, complete the screening questionnaire (will highlight link to this questionnaire).  If you are eligible to participate, we will contact you.  If you have questions for us, contact us:  INTMED-MMOC-PAL-RESEARCH@med.umich.edu (include MEAL in subject of email).