Effect of Amino Acids and Sugar Alcohols on Satiation Peptides and Activation of Specific Brain Regions

Study Overview
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Brief Summary
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With this study the investigators investigate the effects of amino acids (tryptophan, leucin) and sugar alcohols (xylitol, erythritol) on satiety mechanisms and brain activation.

Official Title
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Effect of Amino Acids and Sugar Alcohols on Release of Satiation Peptides and Activation of Specific Brain Regions in Normal Weight and Obese Subjects

Conditions
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Endocrine System Diseases

Intervention / Treatment
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* Dietary Supplement: 1.56 g L-Tryptophan
* Dietary Supplement: 1.56 g L-Leucine
* Dietary Supplement: 50 g Xylitol
* Dietary Supplement: 75 g Erythritol
* Dietary Supplement: 75 g Glucose
* Dietary Supplement: Tap water
* Dietary Supplement: Mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate)
* Device: Nasogastric Tube


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy normal weight subjects with a body-mass index of 19.0-24.9 Healthy obese subjects with a body-mass index of > 30 Normal eating habits (no diets; no dietary changes; no special dietary habits such as vegetarian/vegan) Age 18-40 years Stable body weight for at least three months Exclusion Criteria: Smoking Substance abuse Regular intake of medications (except for oral contraceptives) Medical or psychiatric illness History of gastrointestinal disorders Food allergies Pregnancy, breast feeding Body piercings that cannot be removed History of claustrophobia Left-hander

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 1.56 g L-Tryptophan<br>1.56 g L-Tryptophan in 300 mL tap water given via nasogastric tube + after 60 min: 500ml of a mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate) given via nasogastric tube | Dietary Supplement: 1.56 g L-Tryptophan<br> <br> Dietary Supplement: Tap water<br> <br> Dietary Supplement: Mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate)<br> <br> Device: Nasogastric Tube<br> <br> |
| Active Comparator: 1.56 g L-Leucine<br>1.56 g L-Leucine in 300 mL tap water given via nasogastric tube + after 60 min: 500ml of a mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate) given via nasogastric tube | Dietary Supplement: 1.56 g L-Leucine<br> <br> Dietary Supplement: Tap water<br> <br> Dietary Supplement: Mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate)<br> <br> Device: Nasogastric Tube<br> <br> |
| Active Comparator: 50 g Xylitol<br>50 g Xylitol in 300 mL tap water given via nasogastric tube | Dietary Supplement: 50 g Xylitol<br> <br> Dietary Supplement: Tap water<br> <br> Device: Nasogastric Tube<br> <br> |
| Active Comparator: 75 g Erythritol<br>75 g Erythritol in 300 mL tap water given via nasogastric tube | Dietary Supplement: 75 g Erythritol<br> <br> Dietary Supplement: Tap water<br> <br> Device: Nasogastric Tube<br> <br> |
| Placebo Comparator: 75 g Glucose and mixed liquid meal<br>75 g Glucose in 300 mL tap water given via nasogastric tube + after 60 min: 500ml of a mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate) given via nasogastric tube | Dietary Supplement: 75 g Glucose<br> <br> Dietary Supplement: Tap water<br> <br> Dietary Supplement: Mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate)<br> <br> Device: Nasogastric Tube<br> <br> |
| Placebo Comparator: Tap water and mixed liquid meal<br>300 mL tap water given via nasogastric tube + after 60 min: 500ml of a mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate) given via nasogastric tube | Dietary Supplement: Tap water<br> <br> Dietary Supplement: Mixed liquid meal (Ensure Plus®; 17% protein, 29% fat and 54% carbohydrate)<br> <br> Device: Nasogastric Tube<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of aminoacids on cerebral blood flow measured by functional brain MRI |  | changes from baseline to one hour after treatment | 
| Effect of sugar alcohols on cerebral blood flow measured by functional brain MRI |  | changes from baseline to one hour after treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of Plasma Glucose concentrations |  | changes from baseline to three hours after treatment | 
| Measurement of Plasma Insulin concentrations |  | changes from baseline to three hours after treatment | 
| Measurement of Plasma cholecystokinin concentrations |  | changes from baseline to three hours after treatment | 
| Measurement of Plasma Glucagon-like Peptide (GLP-1) concentrations |  | changes from baseline to three hours after treatment | 
| Measurement of Plasma PYY concentrations |  | changes from baseline to three hours after treatment | 
| Measurement of Plasma ghrelin concentrations |  | changes from baseline to three hours after treatment |