Back to Toddler Index

Dietary Prescription

1. Estimate the recommended intake of protein, energy, and phenylalanine.
   
   
2. Evaluate the appropriateness (based on child’s age) of formula. Phenyl-Free 1* is appropriate for infants and toddlers. Phenyl-Free 2* is appropriate for children and adults.
   
   
3. Calculate the amount of formula to be given; provide 85-90 percent of the protein required for age from formula.
   
   
4. Calculate the phenylalanine, tyrosine, protein, and energy provided by the prescribed amount of formula.
   
   
5. Determine the remaining amount of phenylalanine needed to fulfill the daily phenylalanine prescription and maintain a stable blood phenylalanine level. Negotiate the source of additional phenylalanine (infant formula, e.g., Enfamil, Similac; cow’s milk e.g., whole, lowfat; phenylalanine from food).
   

Consider the amount of food consumed in one day. How much food is it reasonable to expect the toddler to eat? Will foods with high to moderate amounts of phenylalanine need to be used? Will this lead to confusion about "yes" and "no" foods for the toddler? Consider juices as an extra source of energy.

Using milk or infant formula as a source of phenylalanine has several effects on PKU management for infants and young children:

• Allows adjustments of dietary phenylalanine intake without changing the "message" about food. This can simplify many of the issues described above.
• Provides a source of protein
• Stabilizes blood phenylalanine levels


6. Determine the amount of water to mix with the formula. This will vary according to the child's age and fluid requirements. For an older child drinking other fluids, the amount of water added to the formula is relatively arbitrary. The RD should inquire as to what other fluids the child is consuming and how the child prefers the formula. Prescribe water for formula with above information considered. The child may prefer a more concentrated formula if consuming enough fluid from other sources.
   
   
7. Calculate nutrients provided by formula and food prescription to ensure the pattern provides an adequate amount of protein and energy.
   
   

Example: Dietary Calculation for Toddler or Young Child

Child:	2 ½ year old girl
Weight:	12 kg
1. Estimate the recommended intake of protein, energy, and phenylalanine:
	Protein: 25 gm
	Energy: 1000 kcal
	Phenylalanine: 300 mg
2. Evaluate the appropriateness (based on child’s age) of formula:
	This child is over 2 years of age, so Phenyl-Free 2 is appropriate.
3. Calculate the amount of formula to be given (90% of protein supplied by formula):
	25 gm x .90 = 22.5 gm protein from Phenyl-Free 2
	22.5 gm protein / 0.22 = 100 gm Phenyl-Free 2 needed
	(0.22 gm protein per gram Phenyl-Free 2 powder)
4. Calculate phenylalanine, tyrosine, protein, and energy provided by prescribed amount of formula:
	100 gm Phenyl-Free 2:	0 mg phenylalanine
		2200 mg tyrosine
		22 gm protein
		410 kcal energy
5. Determine the remaining amount of phenylalanine needed to fulfill the daily phenylalanine prescription. Negotiate the source:
	Toddler’s established phenylalanine need: 300 mg
	Phenylalanine provided by Phenyl-Free 2:  0 mg______________
	Remaining phenylalanine:                               300 mg
	This toddler generally takes in 80 mg phenylalanine from food, thus 220 mg phe should be provided by whole cow’s milk:
	1 oz milk (31 gm) = 49 mg phenylalanine
	4 ½ oz milk (140 gm) = 220 mg phenylalanine
6. Prescribe water for formula:
	Adding water to 24 oz yields a formula that is approximately 20 calories per ounce. This child typically drinks four 6 oz glasses of formula, so this volume is reasonable.
7. Calculate nutrients provided by formula and food prescription to ensure the pattern provides an adequate amount of protein and energy.
	Formula prescription: 100 gm Phenyl-Free 2, 4 ½ oz whole milk, with water added to make a total volume of 24 oz. This provides 495 kcal energy, 26.5 gm protein, 220 mg phenylalanine.
	Food prescription: 80 mg phenylalanine (will need to provide 505 kcal from food to meet estimated energy needs)