Impact of Phenylketonuria-type Diet on Appetite, Appetite Hormones and Diet Induced Thermogenesis

Not Applicable

Completed

• Conditions: Phenylketonuria (PKU)
• Interventions: Dietary Supplement: Phenylketonuria-type diet; Other: Normal (control) diet

• Registration Number: NCT02440932
• Lead Sponsor: University of Glasgow

Brief Summary

Low-phenylalanine diets are commonly prescribed to people with phenylketonuria (PKU), an inborn disease which causes accumulation of amino acid phenylalanine (Phe) in the blood. High blood Phe levels can cause mental, behavioural, neurological, and physical problems. Thus, low-phenylalanine diets help patients to manage their condition but it is not clear whether they have an impact on appetite, energy intake and changes in body weight. This is important to explore as prevalence of obesity in this population is rising high. This study aims to find out the effect of PKU-type meals on appetite, appetite biomarkers, and post-meal energy expenditure. The investigators will recruit 26 healthy adults and ask them to participate in two experimental trials. On one occasion the participants will be asked to consume a PKU-supplemented drink followed by a PKU type-lunch and on another occasion the supplement and lunch will be based on normally consumed foods. Series of blood samples will be taken and appetite will be assessed during both experiments. Both experimental trials will finish with consuming an "all-you-can-eat" buffet.

Detailed Description

Not available

Study Timeline

• Study Start: 2014-11
• Study First Submitted: 2015-04-30
• Study First Submitted QC: 2015-05-07
• Study First Posted: 2015-05-12
• Primary Completion: 2016-03
• Study Completion: 2016-03
• Status Verified: 2016-05
• Last Update Submitted: 2016-05-20
• Last Update Posted: 2016-05-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 26

Inclusion Criteria

1. Healthy adult
2. Body weight stable for previous 4 months
3. Regular menstrual cycle (females)

Exclusion Criteria

1. Pregnancy or lactation (females)
2. History of eating disorder
3. History of gastrointestinal problems or surgery
4. History of allergy
5. History of chronic illness
6. On any medication
7. Smoking
8. On nutritional supplements
9. Following specific diet
10. Currently taking part in other research

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Phenylketonuria-type diet	Phenylketonuria-type diet	Breakfast: one pouch of amino acid supplement (174 mls supplemented drink PKU cooler 20, Vitaflo®; 20 g protein, 9.4 g carbohydrates, 0.7 g Fat) Lunch: cheese sandwich \[low protein bread (Juvela, UK), no protein vegan cheese (Viotros, UK)\], low protein crackers (Vitaflo, UK), and low protein cookies (Juvela, UK). Dinner: ad libitum buffet meal
Phenylketonuria-type diet	Normal (control) diet	Breakfast: one pouch of amino acid supplement (174 mls supplemented drink PKU cooler 20, Vitaflo®; 20 g protein, 9.4 g carbohydrates, 0.7 g Fat) Lunch: cheese sandwich \[low protein bread (Juvela, UK), no protein vegan cheese (Viotros, UK)\], low protein crackers (Vitaflo, UK), and low protein cookies (Juvela, UK). Dinner: ad libitum buffet meal
Normal diet	Normal (control) diet	Breakfast: 174 ml of milk (20 g protein, 9.4 g carbohydrates, 0.7 g Fat) Lunch: cheese sandwich, crackers, and cookies (regular foods) Dinner: ad libitum buffet meal
Normal diet	Phenylketonuria-type diet	Breakfast: 174 ml of milk (20 g protein, 9.4 g carbohydrates, 0.7 g Fat) Lunch: cheese sandwich, crackers, and cookies (regular foods) Dinner: ad libitum buffet meal

Primary Outcome Measures

Name	Time	Method
Appetite hormone: peptide YY (PYY)	300 minutes	Plasma concentration at baseline (0 minute) and after ingestion of supplement (at 30, 60 and 90 minutes) and lunch (at 120, 150,180, 210, 240, 270 and 300 minutes)
Appetite hormone: glucagon-like peptide-1 (GLP-1)	300 minutes	Plasma concentration at baseline (0 minute) and after ingestion of supplement (at 30, 60 and 90 minutes) and lunch (at 120, 150,180, 210, 240, 270 and 300 minutes)
Appetite hormone: ghrelin	300 minutes	Plasma concentration at baseline (0 minute) and after ingestion of supplement (at 30, 60 and 90 minutes) and lunch (at 120, 150,180, 210, 240, 270 and 300 minutes)
Subjective appetite score	300 minutes	Visual analogue scale (VAS) collected at baseline and after each blood sample collection
Appetite hormone: insulin	300 minutes	Plasma concentration at baseline (0 minute) and after ingestion of supplement (at 30, 60 and 90 minutes) and lunch (at 120, 150,180, 210, 240, 270 and 300 minutes)
Diet induced thermogenesis	300 minutes	Metabolic rate by means of computerised open-circuit ventilated hood system collected at baseline and after each blood sample collection for the duration of 20 minutes
Appetite hormone: cholecystokinin (CCK)	300 minutes	Plasma concentration at baseline (0 minute) and after ingestion of supplement (at 30, 60 and 90 minutes) and lunch (at 120, 150,180, 210, 240, 270 and 300 minutes)

Secondary Outcome Measures

Name	Time	Method
Taste perception of PKU supplements/foods	10 minutes	Immediately after supplement ingestion and lunch consumption
Consumption time for PKU supplements/foods	20 minutes	Maximum 5 minutes for supplement ingestion and maximum 20 minutes for lunch consumption

Trial Locations

Locations (1)

Human Nutrition, School of Medicine, University of Glasgow; 🇬🇧 Glasgow, United Kingdom