| Biological Value (%) is calculated as retained nitrogen/ | | | | gain/protein intake and, although a useful measure |
| absorbed nitrogen X 100. To illustrate how this | | | | when used in growing animals, has little value for |
| provides an evaluation of protein quality, consider a | | | | humans for two reasons. First, this method is not used |
| scenario in which all amino acids in a protein are used | | | | in human experiments because, ethically, human |
| for protein synthesis. Here, retained and absorbed | | | | subjects cannot be deprived of necessary nutrients. |
| nitrogen would be equal and the biological value would | | | | Second, the difference in species growth rates, Le., |
| equal 100%. | | | | lower in humans versus rats, results in errors when |
| Conversely, if some indispensable amino acids are not | | | | animal data are used to estimate human needs. |
| available in the protein source, protein synthesis is | | | | Protein Digestibility-Corrected Amino Acid Score is |
| impaired and some unused nitrogen is excreted from | | | | based on the amino acid content of a food corrected |
| the body, Le., retained nitrogen decreases relative to | | | | for digestibility. The score reflects the limiting |
| absorbed and the biological value drops below 100%. | | | | indispensable amino acids (those amino acids that |
| Consequently, some foods such as complete protein | | | | humans cannot synthesize) in a food. The reference |
| foods (e.g., milk) have high biological values (95%), while | | | | value used is the requirement for a 2-5-year-old |
| incomplete protein foods are much lower (Le., corn | | | | individual. This provides a built-in safety buffer because |
| [60%1). It is not possible to have a biological value > 1 | | | | protein needs of this age group are greater than for |
| 00%. Net Protein Utilization is a similar measure but | | | | adults. |
| involves a direct measure of retained nitrogen, Le., | | | | About information on bodybuilding & fitness . Also did |
| destruction and analysis of the body, and therefore is | | | | you know about conditions & diseases and types of |
| only used with animal studies. | | | | natural supplement . |
| Protein Efficiency Ratio is determined as body mass | | | | |