Impact of Fruit and Vegetables in PKU

Study Overview
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Brief Summary
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In the UK, some fruits and vegetables are permitted without measurement in the diets of people with phenylketonuria (PKU). It is proven that fruits and vegetables containing phenylalanine (Phe) up to 75mg/100g (e.g. carrots, sweet potato, tomatoes) do not affect blood Phe control but it is unknown to what extent fruits and vegetables containing Phe from 76-100mg/100g (e.g. cauliflower, broccoli, beansprouts and asparagus) increase blood Phe levels. In addition, there is very little information about how differently animal and vegetable protein affect blood Phe levels. It is believed that plant protein may have less bioavailability and therefore have less impact on blood Phe control. The investigators aim is to perform a randomized controlled study over 21 weeks in children (5-12y) with PKU. Children will be studied during five different time periods, examining the effect on blood Phe control when increasing Phe intake from vegetables/fruits containing Phe from 76-100 mg/100g vs. animal sources. At the end of the study, fruits and vegetables containing 76- 100mg Phe/100g will continue to be given as exchange-free for 6 months. This is a practical, cost effective study and should bring benefit to all people with PKU following a very restrictive diet both within the UK and throughout the world.

Official Title
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Impact of Fruits and Vegetables on Metabolic Control in Children With PKU

Conditions
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Phenylketonurias

Intervention / Treatment
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* Other: Phase B - Extra 1 Phe exchange from fruits/vegetables containing Phe from 76-100mg/100g
* Other: Phase C - Extra 2 Phe exchanges from fruits/vegetables containing Phe from 76-100mg/100g
* Other: Phase D - Extra 1 Phe exchange from milk or yoghurt
* Other: Phase E - Extra 2 Phe exchanges from milk or yoghurt


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: PKU patients diagnosed by NBS and BH4 deficiencies; Early and continuously treated; Adherent to their prescribed PKU diet consisting of a protein-restricted diet and Phe-free amino acid based protein substitute; In good general health as evidenced by medical history; Able to provide written informed consent/assent (parent/child); Able to comply with the study protocol and take study product according to the opinion of the PI; Patients with good metabolic control (age 5-12y, 120-360μmol/L) with 3 out of 4 levels within range prior to consent (if 2 of 4 above target range but one close to the upper limit, PI to decide if patient can enter the study). Exclusion Criteria: Concomitant diseases / disorders such as renal or gut disease / disorders and diabetes; Dislikes fruits and vegetables containing 76-100 mg of Phe/100g e.g.brocolli or cauliflower; Treated with BH4 (sapropterin); Presence of intercurrent infection; Patients with poor metabolic control (age 5-12y, >360μmol/L).

Ages Eligible for Study
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Minimum Age: 5 Years
Maximum Age: 12 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This is a prospective, randomised controlled study over 21 weeks in children to assess how Phe intake from fruits and vegetables (containing 76-100 mg Phe/100g) vs. animal sources will impact on blood Phe control. This will be followed by a 6 months extension study examining the 'unlimited' use of fruits and vegetables containing Phe 76-100 mg/100g on blood Phe control.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group starting intervention with vegetable protein<br>Phase A followed by Phases B, C, D, E. | Other: Phase B - Extra 1 Phe exchange from fruits/vegetables containing Phe from 76-100mg/100g<br>* Usual low Phe diet + 60g fruits/vegetables containing Phe from 76-100mg/100g<br>Other: Phase C - Extra 2 Phe exchanges from fruits/vegetables containing Phe from 76-100mg/100g<br>* Usual low Phe diet + 120g fruits/vegetables containing Phe from 76-100mg/100g<br>Other: Phase D - Extra 1 Phe exchange from milk or yoghurt<br>* Usual low Phe diet but 1 x 50 mg extra Phe exchange from milk or yoghurt<br>Other: Phase E - Extra 2 Phe exchanges from milk or yoghurt<br>* Usual low Phe diet but 2 x 50 mg extra Phe exchange from milk or yoghurt eaten daily<br>|
| Active Comparator: Group starting intervention with animal protein<br>Phase A followed by Phases D, E, B, C. | Other: Phase B - Extra 1 Phe exchange from fruits/vegetables containing Phe from 76-100mg/100g<br>* Usual low Phe diet + 60g fruits/vegetables containing Phe from 76-100mg/100g<br>Other: Phase C - Extra 2 Phe exchanges from fruits/vegetables containing Phe from 76-100mg/100g<br>* Usual low Phe diet + 120g fruits/vegetables containing Phe from 76-100mg/100g<br>Other: Phase D - Extra 1 Phe exchange from milk or yoghurt<br>* Usual low Phe diet but 1 x 50 mg extra Phe exchange from milk or yoghurt<br>Other: Phase E - Extra 2 Phe exchanges from milk or yoghurt<br>* Usual low Phe diet but 2 x 50 mg extra Phe exchange from milk or yoghurt eaten daily<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Phe levels three times a week of patients with PKU taking extra 1 or 2 exchanges of fruits and vegetables containing 76-100mg of Phe/100g during 4 weeks each. |  | 8 weeks | 
| Blood Phe levels three times a week of patients with PKU taking extra 1 or 2 exchanges of animal protein during 4 weeks each. |  | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood Phe levels three times a week with PKU taking fruits and vegetables containing 76-100mg of Phe/100g without measurement during 6 months. |  | 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fruit and vegetables, Phenylalanine, Animal protein, Vegetable protein