Net Protein Utilization (NPU)
Net Protein Utilization (NPU) and Biological Value (BV) are quantities used to evaluate certain foods in terms of their protein value and the proportion of protein absorbed into the body from the food type and retained for use in the body. These quantities are included in some courses as part of the study of the human digestive system. They are also useful when considering diets and dieting, e.g. for weight loss or muscle gain.
What is Net Protein Utilization (NPU) ?
Definition of Net Protein Utilization:
The Net Protein Utilization (NPU) of a food is the percentage of protein contained in that food which is retained by the body after the food has been eaten.
Net Protein Utilization (NPU) is used to describe the value or usefulness of certain proteins in a diet.
Equations for Net Protein Utilization (NPU):
Simple equation for NPU:
This is equivalent to Biological Value (BV) x Digestibility.
Compare Net Protein Utilization (NPU) with Biological Value (BV)
To compare biological value with net protein utilization it helps to look at the equations side-by-side:
Obviously (from the "x 100" in the equations), the above are expressions of NPU and BV as percentages.
It is useful to be aware of these terms and their meanings but in practise both of these quantities are difficult to evaluate meaningfully because they do not depend only on the foodstuff they relate to but also, at least in part, on the person/organism eating that food and the efficiency of his/her/its digestive system.
Some texts explain the relationship between Net Protein Utilization (NPU) and Biological Value (BV) as:
Net Protein Utilization (NPU) = Biological Value (BV) x Digestibility
according to the above:
See also the digestive system, what are proteins?, amino acids, biological value and related pages on this website.