Can phenylketonuria be treated? Yes, it can be treated, and treatment should begin immediately once diagnosed. The younger the age at which treatment begins, the better the prognosis. Infants are generally treated with low-phenylalanine formula milk. Once the blood phenylalanine concentration drops to an ideal level, natural foods can gradually be added in small amounts, with a preference for adding breast milk, since it contains only one-third the phenylalanine content of cow's milk.

Older infants and children can add foods like milk, porridge, noodles, and eggs. Added foods should follow the principle of being low in protein and phenylalanine. The amount and frequency of these foods should be determined based on the blood phenylalanine concentration. Concentrations that are too high or too low can affect the growth and development of the child. As each child's tolerance to phenylalanine concentration differs, it is necessary to regularly measure the blood phenylalanine concentration during dietary treatment and adjust the diet according to the specific situation of the child, avoiding increased phenylalanine levels or deficiency.