To treat PKU, we must reduce the amount of phenylalanine in the diet so that the body has just enough for growth and tissue repair but no excess. All protein foods contain considerable amounts of phenylalanine, so they must be severely restricted. Nevertheless everyone, including those with PKU, needs to eat a certain amount of protein.
In the PKU diet, special products usually called protein substitutes which have little or no phenylalanine, have been developed. These will provide the protein which a PKU child needs. Your dietitian / doctor will recommend the most appropriate one for your child. This product will contain some extra tyrosine and all of the other amino acids needed for normal growth. The amount required will be carefully tailored by the dietitians and doctors to meet your child’s specific needs.