Phenylketonuria Treatment

Treatments for Phenylketonuria (PKU)

Treatments for Phenylketonuria (PKU)

Phenylketonuria (PKU) is a rare genetic disorder that impacts the body’s ability to metabolize an amino acid known as phenylalanine. This condition, if left untreated, can lead to severe health complications, including intellectual disabilities and developmental delays. However, with proper management and treatment, individuals with PKU can lead healthy and fulfilling lives. The Special Olympics AZ team is breaking down the various treatment options available for individuals who are diagnosed with PKY, including dietary management, medication, and regular monitoring of blood phenylalanine levels. 

How Is Phenylketonuria (PKU) Treated?

Before exploring the various treatment options that are available for individuals with PKU, it’s important to have a basic understanding of phenylketonuria. This genetic disorder is caused by a deficiency in the enzyme phenylalanine hydroxylase, which is responsible for breaking down phenylalanine. As a result, phenylalanine levels can accumulate in the body, leading to toxicity and neurological damage if not properly managed. Most individuals with PKU will be diagnosed very early in life, many as newborns, when undergoing routine PKU screenings that are required in the United States. Treatment will begin immediately upon diagnosis in order to avoid serious health complications that can occur from an untreated buildup of phenylalanine in the body.

Treatment for PKU aims to maintain these phenylalanine levels within a safe range to prevent neurological damage and other complications. The primary treatment modalities for PKU include dietary management, medication, and regular monitoring through blood tests.


Dietary management is the cornerstone of PKU treatment and involves strict adherence to a low-phenylalanine diet. Phenylalanine is an amino acid and a building block of protein, which is also found in foods or drinks that contain aspartame. Adhering to a low-phenylalanine diet means avoiding foods that are high in protein, particularly those rich in phenylalanine, as well as anything containing aspartame, such as diet sodas.

Foods to Avoid

Common foods that individuals who are on a low-phenylalanine diet must avoid include: 

  • Meat and Poultry: Beef, pork, chicken, and other high-protein animal products should be limited or avoided.
  • Fish and Seafood: Fish and seafood are also rich sources of protein and should be restricted in the PKU diet.
  • Dairy Products: Milk, cheese, yogurt, and other dairy products contain phenylalanine and should be avoided.
  • Eggs: Eggs are high in protein and phenylalanine and should not be consumed by individuals with PKU.
  • Legumes and Nuts: Beans, lentils, peanuts, and other legumes are rich sources of protein and should be limited.
  • Grains: Certain grains, such as wheat, oats, and rice, contain moderate levels of phenylalanine and should be consumed in moderation.

In addition to avoiding high-protein foods, individuals with PKU must also steer clear of products containing the artificial sweetener aspartame, as it contains phenylalanine. Many diet sodas or artificially sweetened low sugar or diet beverages contain aspartame and, as such, should be avoided. 

PKU Medication

In addition to dietary management, some individuals with PKU may benefit from medication to help control phenylalanine levels. Individuals with PKU will often work with a team of doctors and dieticians who will closely monitor their condition and their needs, and they may be prescribed certain medicines to aid in the treatment of PKU. A common medicine that is prescribed for individuals is Sapropterin.


Sapropterin, also known as Kuvan, is a medication approved for the treatment of PKU. It works by increasing the activity of the enzyme phenylalanine hydroxylase, thereby reducing phenylalanine levels in the blood. Sapropterin is typically prescribed in conjunction with a low-phenylalanine diet and may be effective in certain individuals with PKU.

Formula for People With PKU

Specialized medical foods and formulas are essential for individuals with PKU to meet their nutritional needs while maintaining strict control over phenylalanine intake. A doctor or dietician can provide more guidance on what formula may be best for your child to consume when dealing with a PKU diagnosis.

Formula for Babies and Toddlers

Infants diagnosed with PKU require a special infant formula that is low in phenylalanine. These formulas are specially formulated to provide essential nutrients while minimizing phenylalanine intake, supporting proper growth and development during the critical early years.

Formula for Older Children and Adults

As individuals with PKU grow older, they may transition to specialized medical foods and formulas designed for older children and adults. These products are tailored to meet the nutritional needs of individuals with PKU while minimizing phenylalanine intake. They may come in various forms, including powders, liquids, and bars, providing flexibility and convenience for individuals managing PKU. Some foods are designed to provide low-protein alternatives to foods that individuals with PKU must avoid, such as PKU approved bread or oats.

Blood Tests

Regular monitoring of blood phenylalanine levels is crucial for managing PKU effectively. Blood tests are typically performed frequently, especially during infancy and childhood, when growth and development are rapid. These tests help healthcare providers assess the effectiveness of treatment and make adjustments to dietary management, medication, and other interventions as needed to maintain phenylalanine levels within the target range.

Phenylketonuria (PKU) is a complex genetic disorder that requires lifelong management and treatment. While there is currently no cure for PKU, appropriate treatment can effectively control phenylalanine levels and prevent neurological damage and other complications associated with the condition. A multidisciplinary approach to PKU management, involving healthcare providers such as metabolic specialists, dietitians, and genetic counselors, is essential for optimizing outcomes and improving the quality of life for individuals with PKU. By following a strict low-phenylalanine diet, utilizing medication when necessary, and undergoing regular monitoring through blood tests, individuals with PKU can minimize the impact of this condition and live healthy, fulfilling lives.

Special Olympics Arizona Back to Top