A low-protein diet is the main treatment for phenylketonuria (PKU). This is because people with PKU lack an enzyme to properly process the amino acid phenylalanine, a component of protein. PKU diets generally do not contain high-protein foods such as meat, eggs, and nuts, or bread and wheat products.

The PKU diet may result in certain nutritional deficiencies. It is important that everyone with PKU see a specialist for nutritional counseling. This is especially important for those considering pregnancy.

Read food labels carefully. Phenylalanine is present in all protein foods and in some nonprotein foods, such as soda pop and artificial sweeteners (for example, aspartame [such as Nutrasweet]). All foods that contain phenylalanine should have "contains phenylalanine" on the label.

Teach siblings, grandparents, caregivers, teachers, and friends about the dietary restrictions. They need to understand that symptoms of the disease will develop if the child does not follow the diet.

As your child grows, following the diet may become more difficult. Some children may rebel against the diet, especially during the teen years, as they gain more independence and are influenced by peers. Allow your child some control by letting him or her choose what to eat from a variety of low-phenylalanine foods. Continue to stress the importance of staying with the diet. Explain how straying from the diet can cause both immediate and long-term consequences, such as lower intelligence.