Child Adult. For Children and Adults with Inborn Errors of the Urea Cycle WND 2 is an iron-fortified medical food powder that is free of nonessential amino acids for children and adults with inborn errors of the urea cycle . The product provides the essential amino acids as well as carbohydrate, fat, essential fatty acids, vitamins, and minerals. Use under direct and continuing supervision of a doctor. Use under direct and continuing supervision of a doctor. Product Features: Provides essential amino acids; does not contain nonessential amino acids. 8.2.