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

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.

Study Overview

• Status: Completed
• Conditions: Phenylketonuria (PKU)
• Intervention / Treatment: Dietary supplement: Phenylketonuria-type diet; Other: Normal (control) diet

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Glasgow, United Kingdom, G31 2ER
    • Human Nutrition, School of Medicine, University of Glasgow

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 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	Dietary supplement: Phenylketonuria-type diet; Breakfast, lunch and open buffet dinner; Other: Normal (control) diet; Breakfast, lunch and open buffet dinner
Other: Normal 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	Dietary supplement: Phenylketonuria-type diet; Breakfast, lunch and open buffet dinner; Other: Normal (control) diet; Breakfast, lunch and open buffet dinner

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Appetite hormone: peptide YY (PYY)	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)	300 minutes
Appetite hormone: glucagon-like peptide-1 (GLP-1)	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)	300 minutes
Appetite hormone: cholecystokinin (CCK)	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)	300 minutes
Appetite hormone: insulin	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)	300 minutes
Appetite hormone: ghrelin	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)	300 minutes
Subjective appetite score	Visual analogue scale (VAS) collected at baseline and after each blood sample collection	300 minutes
Diet induced thermogenesis	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	300 minutes

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: University of Glasgow

Publications and helpful links

General Publications

• Alfheeaid H, Gerasimidis K, Nastase AM, Elhauge M, Cochrane B, Malkova D. Impact of phenylketonuria type meal on appetite, thermic effect of feeding and postprandial fat oxidation. Clin Nutr. 2018 Jun;37(3):851-857. doi: 10.1016/j.clnu.2017.03.005. Epub 2017 Mar 8.

Study record dates

Study Major Dates

• Study Start: November 1, 2014
• Primary Completion (Actual): March 1, 2016
• Study Completion (Actual): March 1, 2016

Study Registration Dates

• First Submitted: April 30, 2015
• First Submitted That Met QC Criteria: May 7, 2015
• First Posted (Estimate): May 12, 2015

Study Record Updates

• Last Update Posted (Estimate): May 23, 2016
• Last Update Submitted That Met QC Criteria: May 20, 2016
• Last Verified: May 1, 2016

More Information

Terms related to this study

• Keywords: appetite; body weight; low Phenylalanine diet; PKU supplements; diet induced thermogenesis
• Additional Relevant MeSH Terms: Metabolic Diseases; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Genetic Diseases, Inborn; Metabolism, Inborn Errors; Brain Diseases, Metabolic; Brain Diseases, Metabolic, Inborn; Amino Acid Metabolism, Inborn Errors; Phenylketonurias
• Other Study ID Numbers: 200130139