To give students feedback on their efforts at evaluating the normal nutritional requirements in infancy and childhood. These fundamentals will be reinforced by comparing and contrasting the dietary requirements of children with PKU.
Fundamental to an understanding of the dietary treatment of phenylketonuria, is a comprehension of normal nutritional requirements in health, and how this is affected in sickness. Published recommended daily allowances give a guide to the macro- and micronutrient requirements needed to promote growth and health in normal children. Food composition tables allow the construction of diets to meet these requirements. For individuals who have a genetic defect affecting metabolism, these charts can also be used to manipulate the diet to limit the consumption of the nutrients for which the metabolic pathways are interrupted (for example phenylalanine in the case of PKU).
Special diets of this complexity are usually designed by the paediatric dietitian and are beyond the scope of this theme session. Equally important is an understanding of the nutritional requirements of the healthy child and how these vary with age. Also important for PKU is an understanding of the mechanisms by which phenylalanine homeostasis may be impaired, and principles which can be employed to correct these metabolic imbalances.
To reinforce the nutritional foundations learnt in the preceding case, the principles of a balanced diet will be reviewed, with particular emphasis on how the body uses protein and amino acids in food. The concepts of nitrogen balance, essential and non-essential amino acids, variation of quality and quantity of protein in food. PKU will be used as an example of how an understanding of these fundamental principles can be practically employed.