Special Diet
Normal protein requirements vary with age. In early infancy requirements can exceed 2g/kg/day, but these needs will decline as the baby gets older. Teen-age boys require about 0.81 g/kg/day and teen-age girls 0.77 g/kg/day. Urea production and excretion are linearly related to protein intake, hence lowering the protein intake will decrease the burden on the urea cycle. In childhood, the goal is to provide enough protein to maintain the child in at least the 50th percentile for height and weight.
Because protein requirements vary throughout infancy and childhood, parents and physicians should work closely with a metabolically trained dietitian in managing the child’s diet. Guidance is needed on basic nutrition and meal planning, preparing school lunches, appropriate snacks, and learning to handle social situations. Adults who are newly diagnosed with urea cycle disorders generally need dietary guidance to learn how to live on a reduced protein intake.
The variability and severity of urea cycle disorders means that each patient’s diet should be customized to meet their specific protein requirements. Dietary resources for low protein formulas, foods, and recipes are available to help parents and patients with meal planning.
| Recommended Ranges for Nutrient Treatment for Urea Cycle Disorders |
|---|
Defective Enzyme |
Age years |
Total |
Protein |
Natural |
Energy |
Free Base |
L-Citrulline |
|
|
|
|
|
|
|
|
| 1-7 | 1.0-1.2 | 0.6-0.7 | 0.4-0.5 | 100-120 | |||
| 7-19 | 0.7-1.4 | 0.4-0.7 | 0.3-0.7 | 80-110 | |||
>19 |
0.5-1.0 |
0.3-0.5 |
0.2-0.5 |
35-65 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Ornithine |
0<1 |
1.2-2.2 |
0.6-1.1 |
0.6-1.1 |
120-145 |
100-500 |
150-500 |
| 1-7 | 1.0-1.2 | 0.6-0.7 | 0.4-0.5 | 100-120 | |||
| 7-19 | 0.7-1.4 | 0.4-0.7 | 0.3-0.7 | 80-110 | |||
| >19 | 0.5-1.0 | 0.3-0.5 | 0.2-0.5 | 35-65 | |||
|
|
|
|
|
|
|
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|
|
|
|||||
Argininosuccinate |
0<1 |
1.2-2.2 |
0.0-0.5 |
0.9-1.7 |
120-145 |
400-600 |
none |
1-7 |
1.0-1.2 |
0.0-0.3 |
0.7-0.9 |
100-120 |
|
|
|
7-19 |
0.7-1.4 |
0.0-0.3 |
0.4-1.1 |
80-110 |
|
|
|
|
>19 |
0.5-1.0 |
0.0-0.2 |
0.3-0.8 |
35-65 |
|
|
|
|
|
|
|
|
|
|
Argininosuccinate |
0<1 |
1.2-2.2 |
0.0-0.5 |
0.9-1.7 |
120-145 |
400-600 |
none |
1-7 |
1.0-1.2 |
0.0-0.3 |
0.7-0.9 |
100-120 |
|
|
|
7-19 |
0.7-1.4 |
0.0-0.3 |
0.4-1.1 |
80-110 |
|
|
|
|
>19 |
0.5-1.0 |
0.0-0.2 |
0.3-0.8 |
35-65 |
|
|
|
|
|
|
|
|
|
|
Arginine |
0<1 |
1.2-2.2 |
0.0-0.5 |
0.9-1.7 |
120-145 |
none |
none |
1-7 |
1.0-1.2 |
0.0-0.3 |
0.7-0.9 |
100-120 |
|
|
|
7-19 |
0.7-1.4 |
0.0-0.3 |
0.4-1.1 |
80-110 |
|
|
|
|
>19 |
0.5-1.0 |
0.0-0.2 |
0.3-0.8 |
35-65 |
|
|
1. Total protein= EAA (essential amino acid mix) + natural protein
2. The high end of the range is for younger children
Reference: Singh, Rani H. and Elsas, Louis J., Nutrition support of patients with disorders of the urea cycle. Metabolic Currents (C308) 1994 produced by Ross Laboratories
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