Developing Biomarkers of Dietary Intake
Condition: Diet Therapy; Healthy Volunteers
Study type: Interventional
Phase: Phase 1

Summary: 
      Background:

      - Researchers who study health and nutrition are interested in developing more accurate
      methods of determining what people eat from day to day and how it affects their general
      health. In particular, better methods are needed to determine if people are accurately
      remembering what they ate. One possible method involves the use of biomarkers, or indicators
      in urine, blood, saliva, fat, and hair, which are related to the intake of a particular food
      in a consistent way. One set of biomarkers in blood samples and hair may be used to determine
      the relative amount of meat, fish, and soda (corn/sugar cane) in a person s diet. However,
      more research is needed to study the effectiveness of using these biomarkers to accurately
      track dietary intake.

      Objectives:

      - To validate the use of biomarkers as representative of specific dietary intake patterns
      (meat/fish/soda).

      Eligibility:

      - Healthy, nondiabetic men between 18 and 65 years of age.

      Design:

        -  This study involves an initial screening visit and a 12-13 week inpatient dietary study
           period.

        -  Participants will be screened with a medical history and physical examination, as well
           as blood and urine samples and a glucose tolerance test to exclude individuals who have
           diabetes.

        -  After 3 days of a standard weight-maintaining diet, participants will have a glucose
           tolerance test and a body fat scan; provide hair, blood, and fat tissue samples; and
           complete questionnaires and performance tests.

        -  Participants will spend one day in a metabolic chamber to measure their energy
           expenditure and general metabolism.

        -  Participants will then be randomized into one of eight carefully designed diets for 12
           weeks. The diets will differ in the amount of meat, fish, and soda, including one diet
           where none of the three biomarker-related foods will be permitted. Blood samples will be
           collected throughout the study diet period.

        -  At the end of the 12-week study diet period, participants will provide additional hair,
           blood, and fat tissue samples, and will have a second metabolism assessment in the
           metabolic chamber.
    

Detailed description: 
      Studies of health and nutrition use a variety of tools to determine what people eat from day
      to day. Unfortunately, most of the methods used are not accurate for a variety of reasons and
      do not provide solid information on which to base health recommendations or public policy. In
      general, when people are asked to keep track of what they eat or recall what they have eaten
      in the past, they make mistakes in estimating both amounts and specifics of what was eaten.
      New tools that can help determine if people are accurately remembering what they ate are
      desperately needed.

      Biomarkers are things that can be measured (in urine, blood, hair, etc.) which are related to
      the intake of a particular food in a consistent way and may therefore be more accurate than a
      food record. One set of biomarkers that may be used are naturally occurring (present in all
      foods) stable isotopes of carbon and nitrogen to determine the relative amount of meat, fish,
      and soda (corn/sugar cane) in a person s diet. These isotopes can be measured in blood
      samples and hair.

      The aim of this study is to validate the use of stable isotope biomarkers as representative
      of specific dietary intake patterns (meat/fish/soda). This study will be an inpatient study
      in which highly specific diets will be fed to volunteers for ~12 weeks and stable isotopes
      will be measured in blood and hair. The ultimate goal is to develop biomarkers to be used to
      validate food intake patterns in outpatient clinical and epidemiological studies.
    

Intervention name(s): 1. Meat, no fish or soda; 2. Meat and soda, no fish; 3. Meat and fish, no soda; 4. Meat and fish and soda; 5. Fish, no meat or soda; 6. Fish and soda, no meat; 7. No meat, fish or soda; 8. Soda, no meat or fish
Intervention type(s): Other; Other; Other; Other; Other; Other; Other; Other
Intervention description(s): weight maintaining diet with meat but no fish or soda; weight maintaining diet with meat and soda but no fish; weight maintaining diet with meat and fish but no soda; weight maintaining diet with meat, fish and soda; weight maintaining diet with fish but no meat or soda; weight maintaining diet with fish and soda but no meat; weight maintaining diet with no meat, no fish, and no soda (vegetarian); weight maintaining diet with soda but no meat or fish (vegetarian + soda)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Fish Diet; Meat Diet; Biomarkers; Stable Isotopes; Dietary Intake