What is PKU?

PKU (Phenylketonuria) is an inherited treatable condition where the body has problems breaking down a particular building block of protein (amino acid) called phenylalanine (Phe). Phe is found in all foods containing protein and can build up in the blood causing harm to the brain. By following a special low phenylalanine (low protein) diet, Phe levels can be kept within the recommended range to avoid/minimise harm.

Apart from needing a special diet, a person with PKU is perfectly healthy. If they eat the wrong foods, they will not be sick straight away, however problems are likely/can occur over the long term. As a person cannot outgrow PKU, maintaining a low protein diet for life is important for good health.

What is a low Phenylalanine Diet?

The low Phenylalanine (Phe) diet consists of four parts. (Your dietitian will recommend the amounts of each of these four parts that a person should have and how often they should have it).

1. Foods low in protein/Phe

Low protein foods can be split into 2 groups:

i. Those naturally low in protein such as:

• Fruits and some vegetables
• Fats and oils and
• Some sweet sugary foods

ii. Specially manufactured low protein food.

• These special foods include low protein mixes, pastas, rice, milk replacers and breads, such as those found in our Loprofin Range.

These foods can be eaten in normal quantities.

2. Foods containing small amounts of protein/Phe

Some foods contain a small amount of protein (and therefore Phe) and may be allowed in the PKU diet. A dietitian can advise if this is safe and how much a person should eat. When including these foods in a PKU diet, it is common to need to count the protein eaten throughout the day.

3. Phe-free Protein Supplement

The remainder of a person’s nutrition will come from specially made Phe-free protein supplements, also known as protein substitutes. These supplements provide all the Phe free protein a person needs for healthy living. It also contains vitamins, minerals and trace elements. Your dietitian will recommend the amount of protein substitute/supplement a person should have and how often they should have it.

4. Foods high in protein/Phe

Foods such as red meat, chicken, fish, eggs, milk, yogurt, cheese, nuts, soybeans, tofu, tempeh and beans are too high in protein to include in a PKU diet, except when the dietary restriction required is minimal. Foods such as regular pasta, bread, rice and starchy vegetables (potatoes, kumera, peas, corn etc.) will likely be limited in the diet as well. This is where the specially made low protein options can be handy.


If you have a child with PKU:


How will PKU affect my child and I?

Discovering that your baby has been diagnosed with PKU can be an emotional time for parents however you should remember that children with PKU treated from early infancy are able to live happy, healthy lives. Learning about the condition and speaking to other PKU families can be a great support and a very useful source of information.

Many parents find that they need support from other families who have children with PKU to feel reassured that their child will be fine. You may find it useful to talk with parents of older children with PKU about how they prepare the special foods and what it is like living with the diet. Seeing other children with PKU who are growing and developing well is reassuring. Speak to your dietitian who may be able to assist you in contacting another family who has been in your position and can show you the excellent outcome that is possible for children with PKU. Patient events are also a great opportunity to meet other families.

How will PKU affect the rest of our family?

It is important for non-PKU siblings to become familiar with the PKU diet too. You can involve your children in meal preparation and encourage them to help prepare foods for their sibling with PKU so that they learn about foods that are part of the PKU diet. When siblings understand that a special diet is necessary for their sibling’s health, their behaviour and positive attitudes can help a child with PKU accept his or her diet.
It is helpful to try and make your child with PKU feel part of family mealtimes. This can be done by basing your child’s PKU meal on the vegetables or grains the rest of the family will be eating. For example, if your family is having pasta with meat sauce for dinner, you can prepare low protein pasta with tomato sauce for your child with PKU.

Please Note: The dietary treatment for PKU varies for each person so all information presented here is for guidance only. Your own dietitian and/or doctor will advise you on all aspects relating to management of PKU for you and your family.