Those with PKU, or phenylketonuria, must avoid or limit their consumption of all foods containing phenylalanine, as they lack the enzyme to convert this amino acid into another, called tyrosine. A buildup of phenylalanine can then cause mental retardation or other neurological problems. This condition can make obtaining proper nutrition very difficult.
This makes the role of the metabolic dietitian crucial. Because of their vast knowledge in diet and physiology, this professional can suggest and modify diets for and with those with PKU and their families. Regular recommendations may include: consuming foods high in tyrosine, getting creative with meals, and planning ahead for vacations, school lunches, and special events, among other things.
If you or someone you know was diagnosed with phenylketonuria, it is important to continue to consult with such a dietitian on this condition, as many of their suggestions and modifications will prove to be extremely helpful to the health of the PKU individual.
This information and more can be found at: http://www.eatright.org/resource/health/allergies-and-intolerances/food-intolerances-and-sensitivities/feeding-the-child-with-pku.