A low-protein diet is the main treatment for phenylketonuria (PKU). This is because people who have PKU lack an enzyme to properly process the amino acid phenylalanine, a part of protein.

Phenylalanine is present in all foods that contain protein. PKU diets typically do not contain high-protein foods such as:

• Meat, eggs, and fish.
• Nuts, peas, and beans (and products made from these foods).
• Milk and cheese.

Phenylalanine is also found in some nonprotein foods, such as the artificial sweetener aspartame and foods and drinks made with aspartame.

Read food labels carefully. All foods that contain phenylalanine should have "contains phenylalanine" on the label.

The PKU diet may result in certain nutritional deficiencies that can slow a person's growth. People who follow this diet need to use a special medical drink, or formula, to help meet their nutrition needs. It is important that everyone with PKU sees a specialist for nutritional counseling.

Teach siblings, grandparents, caregivers, teachers, and friends about the dietary restrictions. They need to understand that symptoms of the disease will develop if your 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. Give your child some control by letting them 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.