Reference protein found in?

PGIMER NO - 2020

Applied Nutrition & Dietetics

Easy

Appeared in: PGIMER NO - 2020

Explanation

Egg protein is designated as the 'reference protein' because it serves as the standard for measuring the quality of other proteins.
It possesses a Biological Value (BV) of approximately 100, indicating that nearly all of its absorbed nitrogen is retained and utilized by the body for tissue synthesis and repair.
Egg contains all nine essential amino acids in the precise proportions required for optimal human health, making it a 'biologically complete' protein.

Option B: Milk protein (casein and whey) is a high-quality, complete protein but has a slightly lower Biological Value (around 90) compared to egg protein. Therefore, it is not the primary reference standard.
Option C: Mutton (meat) is a source of complete protein, but its Biological Value is lower (around 75-80) than that of egg and milk, making it less efficient for the body to use.
Option D: Pea protein is a plant-based protein and is considered 'incomplete' because it is low in one or more essential amino acids, particularly methionine. Its Biological Value is significantly lower (50-60).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Protein Quality and Reference Protein as background academic context rather than a clinical decision trigger.
Understanding protein quality is vital for nurses when creating diet plans for patients with high protein needs, such as those recovering from surgery, burns, or severe infections, to ensure optimal healing.
For patients with conditions like chronic kidney disease, a diet with high Biological Value proteins is recommended to meet nutritional needs while minimizing the production of nitrogenous waste products, thus reducing the load on the kidneys.
What if the patient is a strict vegan and cannot consume eggs or milk? The nurse must educate the patient on protein complementation—combining different plant foods (e.g., rice and beans, or lentils and bread) in the same day to provide all essential amino acids.

How to Approach the Question

First, identify the key term in the question: 'reference protein'.
Recall the definition of a reference protein in nutrition. It is the protein source with the highest quality, used as a benchmark to evaluate other proteins.
Access your knowledge of protein sources and their quality. Remember that egg protein is the gold standard due to its perfect amino acid profile for humans and its high biological value.
Evaluate the given options. While milk, mutton, and pea are all sources of protein, only egg holds the status of the reference protein.
Select the option that matches this established nutritional fact.

Concept Tested & Keywords

QkSKx4pX6NNwmrCbQzv_lR

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) pp. 144-146, 169-171

E6 textbook of Applied Biochemistry and Nutrition & DieteticsHarbans Lal (pp 26-464 of 479) p. 268-270