Uniformity of Food Protein Interpretation Amongst Dietitians for Patients with Phenylketonuria (PKU): 2020 UK National Consensus Statements.

Sharon Evans ,Marjorie Dixon,Sarah Adam,Rachel Pereira,Anita Macdonald,Shirley Judd,Sarah Firman,Catherine Ashmore,Anne Grimsley,Chloe Millington,Joanna Gribben,Lucy White,Anita Emm,Alison Woodall,Moira French,Nicola Mcstravick,Janette Banks,Harriet Churchill,Rachel Skeath,Clare Dale,Kath Singleton,Joy Mcdonald,Jo Males,Charlotte Ellerton,Anne Daly,Catharine Noble,Camille Newby,Abigail Robotham,Ide Herlihy,Suzanne Ford ,J Taylor Cook ,Kathleen Ross ,Sandra Adams ,K Van Wyk ,Fiona J White ,Alex Pinto ,Barbara Cochrane ,Carolyn Dunlop ,Heather Allen ,Madeline H Meier ,Karen A Lang ,Sarah Bailey ,A Terry ,J Wildgoose ,Louise Robertson

doi:10.3390/nu12082205

Abstract

In phenylketonuria (PKU), variable dietary advice provided by health professionals and social media leads to uncertainty for patients/caregivers reliant on accurate, evidence based dietary information. Over four years, 112 consensus statements concerning the allocation of foods in a low phenylalanine diet for PKU were developed by the British Inherited Metabolic Disease Dietitians Group (BIMDG-DG) from 34 PKU treatment centres, utilising 10 rounds of Delphi consultation to gain a majority (≥75%) decision. A mean of 29 UK dietitians (range: 18–40) and 18 treatment centres (range: 13–23) contributed in each round. Statements encompassed all foods/food groups divided into four categories based on defined protein/phenylalanine content: (1) foods high in protein/phenylalanine (best avoided); (2) foods allowed without restriction including fruit/vegetables containing phenylalanine ≤75 mg/100 g and most foods containing protein ≤0.5 g/100 g; (3) foods that should be calculated/weighed as an exchange food if they contain protein exchange ingredients (categorized into foods with a protein content of: >0.1 g/100 g (milk/plant milks only), >0.5 g/100 g (bread/pasta/cereal/flours), >1 g/100 g (cook-in/table-top sauces/dressings), >1.5 g/100 g (soya sauces)); and (4) fruit/vegetables containing phenylalanine >75 mg/100 g allocated as part of the protein/phenylalanine exchange system. These statements have been endorsed and translated into practical dietary management advice by the medical advisory dietitians for the National Society for PKU (NSPKU).

Highlights

Phenylketonuria (PKU) is a rare, inherited metabolic disorder (IMD) caused by phenylalanine hydroxylase deficiency, leading to an abnormal accumulation of blood phenylalanine
All specialist UK PKU IMD centres were represented in each round except for one adult centre only able to participate in two of 10 rounds
Category 4: Fruit/vegetables containing phenylalanine >75 mg/100 g allocated as part of the protein/phenylalanine exchange system (Table 4)

Summary

Introduction

Phenylketonuria (PKU) is a rare, inherited metabolic disorder (IMD) caused by phenylalanine hydroxylase deficiency, leading to an abnormal accumulation of blood phenylalanine. Without treatment, it causes severe and irreversible intellectual disability. National newborn screening programmes detect PKU, which enables treatment to commence in early infancy with outcomes associated with a broad range of normal general ability. In the UK, the only available treatment is a rigorous, life-long dietary restriction of natural protein (i.e., meat, eggs, fish, cheese, nuts, bread, flour, pasta) in order to control blood phenylalanine levels [1,2] within the target range, as pharmacological treatments are not reimbursed by the National Health Service.

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