| Requirements, mg/kg per day, by age group | ||||
|---|---|---|---|---|
| Amino Acid | Infants, Age 3–4 mo b | Children, Age ∼2 yr c | Children, Age 10–12 yr d | Adults e |
| Histidine | 28 | ? | ? | 8–12 |
| Isoleucine | 70 | 31 | 28 | 10 |
| Leucine | 161 | 73 | 42 | 14 |
| Lysine | 103 | 64 | 44 | 12 |
| Methionine plus cystine | 58 | 27 | 22 | 13 |
| Phenylalanine plus tyrosine | 125 | 69 | 22 | 14 |
| Threonine | 87 | 37 | 28 | 7 |
| Tryptophan | 17 | 12.5 | 3.3 | 3.5 |
| Valine | 93 | 38 | 25 | 10 |
| Total without histidine | 714 | 352 | 214 | 84 |
From WHO (1985).
Based on amounts of amino acids in human milk or cow's milk formulas fed at levels that supported good growth. Data from Fomon and Filer (1967).
Based on achievement of nitrogen balance sufficient to support adequate lean tissue gain (16 mg N/kg per day). Data from Pineda et al. (1981).
Based on upper range of requirement for positive nitrogen balance. Recalculated by Williams et al. (1974) from data of Nakagawa et al. (1964).
Based on highest estimate of requirement to achieve nitrogen balance. Data from several investigators (reviewed in FAO/WHO, 1973).
From: 6, Protein and Amino Acids
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