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NCT Number: NCT02440932

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.

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Key information

Conditions

Phenylketonuria (PKU) Amino Acid Metabolism, Inborn Errors Body Weight Brain Diseases Brain Diseases, Metabolic Brain Diseases, Metabolic, Inborn Central Nervous System Diseases Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Metabolic Diseases Metabolism, Inborn Errors Nervous System Diseases Nutritional and Metabolic Diseases Pathological Conditions, Signs and Symptoms Phenylketonurias Signs and Symptoms

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Human Nutrition, School of Medicine, University of Glasgow

Glasgow, G31 2ER, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy adult
  • Body weight stable for previous 4 months
  • Regular menstrual cycle (females)

Exclusion criteria

  • Pregnancy or lactation (females)
  • History of eating disorder
  • History of gastrointestinal problems or surgery
  • History of allergy
  • History of chronic illness
  • On any medication
  • Smoking
  • On nutritional supplements
  • Following specific diet
  • Currently taking part in other research

Treatment and study plan

Phenylketonuria-type diet

Dietary Supplement

Breakfast, lunch and open buffet dinner

Normal (control) diet

Other

Breakfast, lunch and open buffet dinner

Primary outcomes

  1. Appetite hormone: peptide YY (PYY)

    Time frame: 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)

  2. Appetite hormone: glucagon-like peptide-1 (GLP-1)

    Time frame: 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)

  3. Appetite hormone: cholecystokinin (CCK)

    Time frame: 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)

  4. Appetite hormone: insulin

    Time frame: 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)

  5. Appetite hormone: ghrelin

    Time frame: 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)

  6. Subjective appetite score

    Time frame: 300 minutes

    Visual analogue scale (VAS) collected at baseline and after each blood sample collection

  7. Diet induced thermogenesis

    Time frame: 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

Secondary outcomes

  1. Taste perception of PKU supplements/foods

    Time frame: 10 minutes

    Immediately after supplement ingestion and lunch consumption

  2. Consumption time for PKU supplements/foods

    Time frame: 20 minutes

    Maximum 5 minutes for supplement ingestion and maximum 20 minutes for lunch consumption

Sponsors and collaborators

Lead sponsor

University of Glasgow

Other

Registry information

Important dates

Study start
2014
Primary completion
2016
Study completion
2016
First posted
May 12, 2015
Registry last updated
May 23, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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