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

Nutrients. 2020 Jul 24;12(8):2205. doi: 10.3390/nu12082205.


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).

Keywords: Delphi method; Phe; consensus; exchanges; food labelling; phenylalanine; phenylketonuria (PKU); protein.

MeSH terms

  • Consensus
  • Delphi Technique
  • Diet, Protein-Restricted / methods
  • Diet, Protein-Restricted / standards*
  • Dietary Proteins / analysis*
  • Dietetics / standards*
  • Food Labeling / standards
  • Humans
  • Phenylalanine / analysis*
  • Phenylketonurias / diet therapy*
  • United Kingdom


  • Dietary Proteins
  • Phenylalanine