Effects of Fruit Juices on Hormone Metabolism

Study Overview
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Brief Summary
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The purpose of this study is to determine whether grapefruit juice alters the metabolism of cortisol following intense exercise.

Official Title
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Effect of Grapefruit Juice and Exercise on Cortisol Levels

Conditions
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Cortisol

Intervention / Treatment
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* Other: Grapefruit juice
* Other: Apple juice


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Young men and women, not taking medications known to alter glucocorticoid metabolism Exclusion Criteria: Diabetes, uncontrolled hypertension, obesity, any medication known to interact with grapefruit juice

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Grapefruit juice<br>12.5 OZ Grapefruit juice: Subject will ingest grapefruit juice 12.5 OZ twice on the day of their scheduled laboratory visit. Once in the morning and once in the afternoon prior to their evening visit | Other: Grapefruit juice<br>* Volunteers participate in two visits at least 5 days apart. The day of their visit they ingest 12.5 oz of grapefruit juice in the morning and 12.5 oz of grapefruit juice ingested in the afternoon, 3h before reporting to the laboratory. The order of the visits is randomized, one visit volunteers ingest apple juice only, the other visit grapefruit juice only<br>|
| Placebo Comparator: Apple juice<br>10.5 OZ Apple juice: Subject will ingest apple juice 10.5 OZ twice on the day of their scheduled laboratory visit. Once in the morning and once in the afternoon 3 hours prior to their evening visit. | Other: Apple juice<br>* Volunteers participate in two visits at least 5 days apart. The day of their visit they ingest 12.5 oz of grapefruit juice or Apple juice ingested in the morning and 12.5 oz of grapefruit juice ingested in the afternoon, 3h before reporting to the laboratory. The order of the visits is randomized, one visit volunteers ingest apple juice only, the other visit grapefruit juice only<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma cortisol change from baseline at 45 minutes | Plasma cortisol levels will be collected at baseline and 45 minutes post-exercise for the Grapefruit visit intervention and for the Apple juice intervention. The interventions are acute ( 1 day), there is no follow up. The interventions are at least 1 week apart. For a given subject, the estimated time for study completion for the 2 treatments is 14 to 30 days. | Baseline, 45 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in plasma cortisol from 15 minutes to baseline | Plasma cortisol levels will be collected at baseline and 15 minutes post-exercise for the Grapefruit visit intervention and for the Apple juice intervention. The interventions are acute ( 1 day), there is no follow up. The interventions are at least 1 week apart. For a given subject, the estimated time for study completion for the 2 treatments is 14 to 30 days. | baseline, 15 minutes |