National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Background: Dopamine is a chemical that the brain makes when a person expects a reward. Researchers want to learn more about how eating different types of food affects dopamine levels in the brain. Objective: To test how eating different foods affects dopamine levels in the brains of healthy people. Eligibility: Healthy people aged 18 to 45 years old. Design: Participants will be divided into 2 groups (cohorts). Both will have overnight stays in the clinic. All participants will be screened. They will talk to a dietitian about their eating habits. They will have a test of how much energy their body uses: They will lie on a table with a clear hood over their heads to measure the gases as they breathe. During the 3 weeks before participants stay at the clinic, a dietitian will call at 3 random times to ask what they ate the day before. They will complete questionnaires. Cohort 1 will wear a device to track their step count for at least 7 days; these participants will be given food to eat for 2 days before they stay in the clinic. Cohort 1 will stay in the clinic for 14 days. They will eat as much or as little as they would like on 2 different diets for 5 days each and a normal diet on the other days. They will have blood collected multiple times. They will have 2 d ifferent types of imaging scans. For 1 type, they will receive a drug through a vein to show how much dopamine is in their brains. Cohort 2 will stay in the clinic for 2 days. They will eat only the foods provided. They will have imaging scans before and after drinking a milkshake. For both scans, they will receive a drug through a vein to show how much dopamine is in their brains. They will have blood collected multiple times.
Study Description: In this single-site study, we will recruit a cohort of 32 adult volunteers to a randomized crossover diet study to investigate change in dopamine D2 receptor availability (via \[11C\]raclopride binding potential). During their participation, after a 2-day outpatient stabilization diet, participants will be admitted for a 14-day, 13-night inpatient stay at the NIH Clinical Center. Following 2 days of inpatient stabilization diet, participants will consume two ad libitum test diets with distinct proportions of ultra-processed food for 5 days each in random order separated by…
* INCLUSION CRITERIA In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Aged 18 to 45 years old 2. In good general health as evidenced by medical history 3. Weight stable (\< +/- 5% change in last 6 months), based on self-report 4. BMI 1. Cohort 1: 18.5 - 24.9 kg/m\^2 2. Cohort 2: \>= 18.5 kg/m\^2 EXCLUSION CRITERIA An individual who meets any of the following criteria will be excluded from participation in this study: 1. Body weight \> 400 lbs. (weight limit of PET scanner) 2. History or current self-report of conditions…
The drug is intended for use as a radiopharmaceutical for positron emission tomography (PET) administered at a maximum prescribed dose of 20mCi and will be administered intravenously via indwelling catheter
The \~8 oz liquid meal will be high in both dietary fat and sugar and ultra-processed designation based on ingredients and will be prepared by the NIH Clinical Center Metabolic Kitchen for participant consumption during the PET scans at the end of both test dietary intervention periods (Cohort 1) or for consumption between the PET scans (Cohort 2).
The control stimulus is a non-rewarding tasteless solution with viscosity distinct from pure water (i.e., artificial saliva). Four dilutions of 25mM potassium chloride + 2.5mM sodium bicarbonate will be prepared by NIH Clinical Center Pharmacy for participant oral stimulus taste test
The minimally processed diet will derive \~80% of calories from minimally processed foods and will contain no ultra-processed foods, (NOVA 1-3), as defined by the degree, extent, and purpose of processing according to the NOVA classification system. The minimally processed diet will be matched to the ultra-processed diet for presented macronutrients, sugar, sodium, and fiber. This diet will be low in both non-beverage energy density and hyper-palatable foods
The ultra-processed diet will derive \~80% of energy from ultra-processed foods (NOVA 4), as defined by the degree, extent, and purpose of processing according to the NOVA classification system. The ultra processed diet will be matched to the minimally processed diet for presented macronutrients, sugar, sodium, and fiber. This diet will be high in both non-beverage energy density and hyper-palatable foods.
The baseline (control) diet will be composed of 50% of energy from ultra-processed foods while matching distribution of macronutrients presented in test diets and total sugar, sodium, and fiber). Energy needs will be estimated using resting energy expenditure multiplied by an appropriate activity factor collected at screening visit to facilitate production by the NIH Metabolic Kitchen.