Net protein utilization
The net protein utilization (NPU) is the percentage of ingested nitrogen that is retained in the body.
Rating
[edit]It is used to determine the nutritional efficiency of protein in the diet,[1]: 11 that is, it is used as a measure of "protein quality" for human nutritional purposes.[2]
As a value, NPU can range from 0 to 1 (or 100), with a value of 1 (or 100) indicating 100% utilization of dietary nitrogen as protein and a value of 0 an indication that none of the nitrogen supplied was converted to protein.
Certain foodstuffs, such as eggs or milk, rate as 1 on an NPU chart.
Experimentally, this value can be determined by determining dietary protein intake and then measuring nitrogen excretion. One formula for apparent NPU is:[3]
- NPU = {0.16 × (24 hour protein intake in grams)} - {(24 hour urinary urea nitrogen) + 2} - {0.1 × (ideal body weight in kilograms)} / {0.16 × (24 hour protein intake in grams)}
NPU and biological value (BV) both measure nitrogen retention; the difference is that biological value is calculated from nitrogen absorbed, whereas net protein utilization is from nitrogen ingested.[4] Another closely related quantity is the net postprandial protein utilization (NPPU), which is the maximum potential NPU of a dietary protein source under ideal conditions.[1]: 12
The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is a more modern rating for determining protein quality, and the current ranking standard used by the FDA.
The Digestible Indispensable Amino Acid Score (DIAAS) is a protein quality method, proposed in March 2013 by the Food and Agriculture Organization[5] to replace the current protein ranking standard, the Protein Digestibility Corrected Amino Acid Score (PDCAAS). The proposition is contested, however, due to lack of data.[6]
See also
[edit]References
[edit]- ^ a b "Scientific Opinion on Dietary Reference Values for protein: Dietary Reference Values for protein". EFSA Journal. 10 (2): 2557. February 2012. doi:10.2903/j.efsa.2012.2557. hdl:2434/257730. S2CID 139100064.
- ^ Protein Quality–The 4 Most Important Metrics
- ^ Blackburn, GL; Bistrian, BR; Maini, BS; Schlamm, HT; Smith, MF (1977). "Nutritional and metabolic assessment of the hospitalized patient". Journal of Parenteral and Enteral Nutrition. 1 (1): 11–22. doi:10.1177/014860717700100101. PMID 98649.
- ^ Hoffman, JR; Falvo, MJ (September 2004). "Protein - Which is Best?". Journal of Sports Science & Medicine. 3 (3): 118–30. PMC 3905294. PMID 24482589.
- ^ "FAO proposes new protein quality measurement - IFT.org". 2017-05-19. Archived from the original on 2017-05-19. Retrieved 2020-11-03.
- ^ "Potential impact of the digestible indispensable amino acid score as a measure of protein quality on dietary regulations and health". ResearchGate. Retrieved 2020-11-03.