In children with PKU the protein food cannot be used properly. Foods which supply most of the protein in our diet include meat, fish, poultry, egg, milk and cheese but reasonable amounts of protein are found in certain cereals and vegetables such as wheat, rice, peas, beans and lentils. All of these proteins are made up of substances or ‘building blocks’ called amino acids.
There are many different types of amino acid and each protein food contains these in varying amounts. This is why each protein food looks and tastes different from another eg milk does not look and taste like meat.
Phenylalanine is one of these amino acids and it is this particular one which the PKU child cannot deal with properly.