ANSWER
Dietary protein is composed of essential and non-essential amino acids. Essential amino acids are histidine, tryptophan, lysine, methionine, phenylalanine, threonine, valine, leucine and isoleucine. Non-essential amino acids include alanine, arginine, asparagine, glutamic acid, glutamine, ornithine, selenocysteine, tyrosine, glycine, cysteine, proline, serine and aspartic acid.
Table 1 shows the essential amino acid requirement for Adults (Age>18 years old).
Table 1: Essential Amino Acid Requirements for Adults (Age>18 years old)
| Amino Acid Protein | Amino acid requirements (mg/kg per day) | *Scoring Amino acid requirements (mg/g protein) |
| Histidine | 10 | 15 |
| Isoleucine | 20 | 30 |
| Leucine | 39 | 59 |
| Lysine | 30 | 45 |
| Sulphur amino acid (Mehionine + Cysteine) | 15 | 22 |
| Aromatic amino acid (Phenylalanine + tyrosine) | 25 | 38 |
| Threonine | 15 | 23 |
| Trytophan | 4 | 6 |
| Valine | 26 | 39 |
* 0.66g protein/kg per day
(Food and Agriculture Organization of the United Nations, 2011).
Reference
Food and Agriculture Organization of the United Nations (2011). Dietary Protein Quality Evaluation in Human Nutrition. (P. 27). ISSN 0254-4725.
