These figures below is an estimate of the required dietary allowance (RDA) of essential amino acids - that being those amino acids that can not be synthesized by the body.
When consuming an adequate amount of essential amino acids, the person will be classed as being in "nitrogen equilibrium", since nitrogen balance studies are conducted to determine the amounts of these essential amino acids required by various people, and this balance is reached when the intake of nitrogen from protein is approximately equal to the nitrogen lost in the feces and urine.
| Requirement - mg. per kg. of body weight | |||
|---|---|---|---|
| infant | child | adults | |
| AMINO ACID | 3 - 6 mo. | 10 - 12 yr. | |
| Histidine | 33 | not known | not known |
| Isoleucine | 80 | 28 | 12 |
| Leucine | 128 | 42 | 16 |
| Lysine | 97 | 44 | 12 |
| S-containing amino acids | 45 | 22 | 10 |
| Aromatic amino acids | 132 | 22 | 16 |
| Threonine | 63 | 28 | 8 |
| Tryptophan | 19 | 4 | 3 |
| Valine | 89 | 25 | 14 |