Ghrelin Regulation and Structure: Effect of Diet Composition on Ghrelin

Study Overview
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Brief Summary
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The purpose of this study is to learn more about how diet affects the hormone ghrelin. Ghrelin is made in the stomach and causes appetite to increase. Learning about ghrelin will help the investigators understand more about obesity.

Detailed Description
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Control subjects will be provided 3 different diets for 2 weeks each. At the end of each diet period participants will be admitted to OHSU Clinical Translation Research Center (CTRC) for blood sampling every 30 minutes for 13.5 hours, to measure levels of hormones. Participants will also have a DXA scan to measure body composition. PWS subjects will have one admission after eating a standardized diet prepared by caregivers for 2 weeks.

Official Title
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Ghrelin Regulation and Structure: Effect of Diet Composition on Ghrelin

Conditions
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Obesity

Intervention / Treatment
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* Dietary Supplement: Low fat diet
* Dietary Supplement: High fat diet
* Dietary Supplement: MCT diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18 or older. Weight stable for at least 3 months. At lifetime maximal body weight. Exclusion Criteria: Actively losing weight by diet or exercise. Smokers. Alcohol consumption > 2 drinks per day. Exercise > 30 minutes 3 times a week. Prescription drug use (except birth control pills, vitamins, or minerals). Type 2 diabetes. Heart disease, cancer, malabsorptive states, or chronic infections that would affect body weight. Weight > 300 lbs (exceeds the weight limit of the DEXA machine). Hemoglobin < 12.0 g/dL for women, < 13.5 g/dL for men

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: 1<br>low fat diet for two weeks. | Dietary Supplement: Low fat diet<br>* 20% fat diet<br>|
| Active Comparator: 2<br>High fat diet for two weeks followed by blood sampling. | Dietary Supplement: High fat diet<br>* 40% fat diet<br>|
| Active Comparator: 3<br>Medium Chain Triglyceride diet | Dietary Supplement: MCT diet<br>* Medium chain triglyceride diet<br>* Other names: Medium chain triglyceride diet;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The primary outcomes for aim 1 are the suppression of total and acylated ghrelin from peak fasting (highest value) level to nadir (lowest level) during the 4 hours after each meal, comparing the obese to the lean subjects. |  | every 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Area-under-the-curve measurements during the 12 ½ hours of testing for ghrelin and other nutrient and gut-peptides, including glucose, insulin, PYY3-36, and active GLP-1. |  | Every 8 weeks |