Whey Protein Study - Identification of Sustainable Satiety

Study Overview
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Brief Summary
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This study will have the primary aim to investigate within-day changes in appetite after consumption of high-protein (HP, 30% of calories) and normal, or low, protein (LP, 15% of calories) whey protein meal, in solid and liquid form, on appetite and ad libitum food intake. Secondary objective will be to assess the statistical relationship between plasma concentrations of gut hormones and visual analogue scales (subjective hunger and fullness) and transit time. In order to investigate the interaction of food structure and protein content on appetite, this requires, in practice, either a differing amount (g) or calorie (kJ) load as a function of energy density (defined as kJ/100g). Delivering the test meal as a solid and liquid form gives an easy solution to achieve this manipulation without compromising the nutritional profile. Following on from this decision, it is easier to produce different preloads using whey protein (rather than meat protein), since it is easily incorporated into test meals.

Detailed Description
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A randomized crossover design in 10 overweight/obese (BMI 26-40) men and 10 lean men (BMI 18.5-25). The control will be water. Each subject will attend the HNU on six separate occasions. The five test meal challenges will involve subjects attending the Human Nutrition Unit (HNU) in the morning, after an overnight fast. The total time of test meal visits will be approximately 4½hours. They will be provided with a standardised meal, after which blood samples will be collected for the first 2hrs. The following five treatments will be tested: Treatment 1 Control - Water + Egg Yolk Mixture + 13C Octanoic Acid Treatment 2 HPL (High Protein Liquid): 30% protein; 30% fat and 40% carbohydrate (CHO) Treatment 3 LPL (Low Protein Liquid): 15% protein; 30% fat and 55% CHO Treatment 4 HPS (High Protein Solid): 30% protein; 30% fat and 40% CHO Treatment 5 LPS (Low Protein Solid): 15% protein; 30% fat and 55% CHO Test meals will be of fixed nutritional composition for all participants. The liquid meal will be a milk/fruit smoothie mixture and the 'solid' will be in a milk jelly (set) form. Ad libitum pasta meal: 15% protein; 30% fat and 55% CHO as a homogenous mix and energy density of around 400kJ/100g - served in excess as a individual 600g portion to 'help-yourself'. Subjective average appetite will be measured (every 30 min by visual analogue scales) over 4hr and ad libitum food intake will measured 4hr after treatment consumption. Ad libitum lunch will be a homogenous pasta meal with tomato sauce and a bottle of water. Blood samples will be collected every 10 min for the first half hour, every 15 min for the second half hour and every 30mins subsequently. The breath gastric emptying measurement will be assessed using the 13Carbon (13C) Octanoic Acid stable isotopic technique19. This involves mixing the tracer into food and taking breath samples and measured by isotope ratio mass spectrometry. 13C Octanoic acid is a medium chain fatty acid which is rapidly absorbed in the duodenum and metabolised in the liver. Following oxidation, the resulting Carbon Dioxide (CO2) is excreted into breath (12 samples will be collected during the 4hr test day).

Official Title
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Whey Protein Study - Identification of Sustainable Satiety

Conditions
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Satiety

Intervention / Treatment
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* Dietary Supplement: Control
* Dietary Supplement: HPL
* Dietary Supplement: LPL
* Dietary Supplement: HPS
* Dietary Supplement: LPS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI = 18.5-40kg/m2 Exclusion Criteria: Diabetes Severe gastrointestinal disorders Kidney disease Thromboembolic or coagulation disease Hepatic disease Alcohol or any other substance abuse Gout Eating disorders Food allergy Unregulated thyroid disease Psychiatric disorders (including severe depression, lithium treatment, schizophrenia, severe behavioural disorders) Vegetarians & Vegans Medication Exclusion Criteria: Orlistat (Xenical) Oral antidiabetics, insulin Rimonabant (Acomplia) Digoxin, anti-arrhythmics Sibutramine (Reductil) Tricyclic antidepressants, neuroleptics

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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Male

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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Treatment 1 - Control<br>Water, Toast & Egg (Yolk only) + 0.1g 13C Octanoic Acid | Dietary Supplement: Control<br>* Water, Toast & Egg (Yolk only) + 0.1g 13C Octanoic Acid<br>|
| Active Comparator: Treatment 2 - HPL<br>High Protein Smoothie (Liquid): 30% protein; 30% fat and 40% CHO + 0.1g 13C Octanoic Acid | Dietary Supplement: HPL<br>* High Protein Smoothie (Liquid): 30% protein; 30% fat and 40% CHO + 0.1g 13C Octanoic Acid<br>|
| Active Comparator: Treatment 3 - LPL<br>Low Protein Smoothie (Liquid): 15% protein; 30% fat and 55% CHO + 0.1g 13C Octanoic Acid | Dietary Supplement: LPL<br>* Low Protein Smoothie (Liquid): 15% protein; 30% fat and 55% CHO + 0.1g 13C Octanoic Acid<br>|
| Active Comparator: Treatment 4 - HPS<br>High Protein Milk Jelly (Solid): 30% protein; 30% fat and 40% CHO + 0.1g 13C Octanoic Acid | Dietary Supplement: HPS<br>* High Protein Milk Jelly (Solid): 30% protein; 30% fat and 40% CHO + 0.1g 13C Octanoic Acid<br>|
| Active Comparator: Treatment 5 - LPS<br>Low Protein Milk Jelly (Solid): 15% protein; 30% fat and 55% CHO + 0.1g 13C Octanoic Acid | Dietary Supplement: LPS<br>* Low Protein Milk Jelly (Solid): 15% protein; 30% fat and 55% CHO + 0.1g 13C Octanoic Acid<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in postprandial biomarkers of satiety as measured by gut-related hormones | The biomarkers to be measured on the Luminex system are Ghrelin (active), Glucagon-like peptide (GLP1), Peptide YY (PYY), Amylin, Leptin & Insulin Biomarkers of Cardiovascular Disease (CVD) risk including total cholesterol, Low Density Lipoprotein Cholesterol (LDL), High Density Lipoprotein (HDL), triglycerides, nonesterified fatty acids (NEFA) will also be measured along with assessment of peripheral glycaemic control, fasting glucose, area under the curve combined with insulin data. | On each test day blood samples are collected every 10 min for the first half hour, every 15 min for the second half hour and every 30mins subsequently. (Eight samples are therefore collected for 2hours at T0, T10, T20, T30, T45, T60, T90 and T120mins) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in postprandial gastric emptying, measured using breath samples | This is assessed using the 13C Octanoic Acid stable isotopic technique. A tracer is mixed into food and breath samples are collected which are analysed by isotope ratio mass spectrometry. 13C Octanoic acid is a medium chain fatty acid which is rapidly absorbed in the duodenum and metabolised in the liver. Following oxidation, the resulting CO2 is excreted into breath (12 samples will be collected during the 4hr test day). | On each test day samples are collected every 15mins for the first 2½hrs then every 30mins for the last ½hr. Therefore samples are collected for a total of 3hours at T0, T15, T30, T45, T60, T75, T90, T105, T120, T135, T150 and T180mins. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Appetite, Gut Hormones, Protein, Energy Density, Gastric Emptying