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Phenylketonuria (PKU) | Protein metabolism | Inborn Errors of Metabolism

Phenylketonuria (PKU)

What is Phenylketonuria (PKU)?

The ‘building blocks’ of protein are called amino acids. In PKU, due to the lack of an enzyme, the body cannot properly deal with one of the amino acids, phenylalanine. People with PKU therefore need to severely restrict the amount of protein they eat.


A key element in the management of PKU is the use of protein substitutes. Protein substitutes for PKU provide all the amino acids found in protein but no phenylalanine. In combination with the small allowance of regular dietary protein, protein substitutes ensure that an individual with PKU has an adequate intake of protein. 


Vitaflo produces a range of age-specific, lifestyle-friendly and palatable protein substitutes for PKU.


Our product range for PKU


Our support product range 


Our healthcare professional resources for PKU


PKU case studies

Starting Solids and Introducing a Second Stage Protein Substitute (PKU gel™)



Prof. Anita MacDonald, Consultant Dietitian in Inherited Metabolic Disorders, Birmingham Children’s Hospital


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Use of PKU sphere® as a protein substitute during pregnancy.



Claire Nicol, Specialist Metabolic Dietitian, Great Northern Children’s Hospital (Royal Victoria Infirmary), Newcastle Upon Tyne


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Online resource for PKU patients


Inborn Errors of Metabolism