What is the Net Protein Utilisation (NPU) value of egg?

NIA - 29 January 2023

Applied Nutrition & Dietetics

Easy

Appeared in: NIA - 29 January 2023

Explanation

Egg protein is considered the 'gold standard' or 'reference protein' because it has a nearly perfect essential amino acid profile and high digestibility.
For comparative purposes in nutrition, the reference protein is assigned a benchmark value of 100.
While the directly measured Net Protein Utilisation (NPU) for an egg is around 91, its Chemical Score is 100, and it is conventionally referred to with the value of 100 in multiple-choice questions to represent this standard.
Among the given options, 100 is the most appropriate answer, reflecting the egg's status as the reference standard for protein quality.

Option A: An NPU of 25 is extremely low and would be characteristic of a very poor-quality or incomplete protein source, which is not the case for eggs.
Option B: An NPU of 50 is incorrect for eggs. This value is more representative of plant-based proteins like wheat (NPU 47) or Bengal gram (NPU 47), which have lower protein quality than eggs.
Option C: An NPU of 75 is incorrect for eggs. This value is closer to the NPU of other high-quality animal proteins like milk (NPU 75) or meat (NPU 76), but still lower than that of eggs.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The concept tested is the Net Protein Utilisation (NPU) value of egg protein, which is a key topic in nutritional science as background academic context rather than a clinical decision trigger.
Understanding protein quality is crucial for nurses when planning diets for patients with increased metabolic needs, such as those recovering from surgery, burns, or severe infections.
High NPU foods like eggs are recommended to ensure efficient tissue repair and synthesis of essential body proteins (e.g., albumin, antibodies).
A nurse might advise a vegetarian patient to combine different plant proteins (e.g., cereals and pulses) to improve the overall protein quality of their diet, a concept known as mutual supplementation.

How to Approach the Question

First, identify the key terms in the question: 'Net Protein Utilisation (NPU)' and 'egg'.
Recall that NPU is a measure of protein quality.
Remember from nutritional science that egg protein is used as the 'reference protein' or the standard against which other proteins are compared.
Recognize that the standard or reference is typically assigned a value of 100 for scoring and comparison purposes.
Evaluate the options. Even if you recall the exact measured NPU is slightly less than 100 (e.g., 91), the value '100' is the conventional answer in this context, representing its role as the benchmark. Select 100 as the best fit.

Concept Tested & Keywords

Concept Tested: The concept tested is the Net Protein Utilisation (NPU) value of egg protein, which is a key topic in nutritional science.
Stem keywords: Net Protein Utilisation, NPU, egg
Lead-in keywords: What is

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