Which of the following is an essential amino acid?

Appeared in: AIIMS Patna NO - 2020

Explanation

Valine is one of the nine essential amino acids, which are the building blocks of protein.
Essential amino acids cannot be synthesized by the human body and must be obtained from dietary sources.
According to nutritional science, Valine is critical for muscle growth, tissue repair, and energy production.
Foods rich in Valine include soy, cheese, peanuts, mushrooms, whole grains, and vegetables.

Option A: Niacin is a nutrient, but it is classified as a B-complex vitamin (Vitamin B3), not an amino acid.
Option B: Thiamine is Vitamin B1. Like Niacin, it is a water-soluble vitamin essential for metabolism, not an amino acid.
Option C: Pyridoxine is Vitamin B6. While it is involved in amino acid metabolism, it is a vitamin itself, not a building block of protein.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Nutrients: Essential Amino Acids vs. Vitamins as background academic context rather than a clinical decision trigger.
Nurses must understand basic nutrition to assess patients, plan care, and provide education. Differentiating macronutrient components (like amino acids) from micronutrients (like vitamins) is fundamental.
In patients with conditions like severe burns, trauma, sepsis, or Protein-Energy Malnutrition (PEM), providing a diet with all essential amino acids is critical for synthesizing proteins needed for wound healing, immune function, and recovery.
What if? If a patient has a genetic metabolic disorder like Maple Syrup Urine Disease (MSUD), the context changes. In MSUD, the body cannot properly process the branched-chain amino acids (BCAAs) Leucine, Isoleucine, and Valine. In this case, intake of Valine would need to be strictly restricted, not encouraged.

How to Approach the Question

First, identify the key term in the question stem: 'essential amino acid'. This tells you the question is about a specific category of nutrients.
Next, analyze each option to determine its classification.
Recall or recognize that 'Niacin' (B3), 'Thiamine' (B1), and 'Pyridoxine' (B6) are all names of B-vitamins.
This process of elimination leaves 'Valine' as the only option that is an amino acid.
Confirm your knowledge that Valine is indeed one of the nine essential amino acids that must be obtained from the diet.

Concept Tested & Keywords

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E6 Nutrition Monika Sharma 3e p. 87-89

E6 Pharmacology Nursing Lilley 11e Part 3 p. 231-233

Practise the full AIIMS Patna NO - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.