Amino acid deficient in wheat is?

Appeared in: HPSSC Staff Nurse - 2021

Explanation

Wheat is a staple cereal grain.
Cereal proteins are generally considered incomplete because they are deficient in the essential amino acid Lysine.
This deficiency makes Lysine the 'limiting' amino acid, meaning its scarcity limits the body's ability to synthesize new proteins, even if other amino acids are plentiful.
The protein content of wheat has Lysine and Threonine as its limiting amino acids.

Option A: Leucine is a branched-chain amino acid that is generally abundant in cereals like wheat. In fact, some cereals like maize can have an excess of leucine.
Option B: Methionine, a sulfur-containing amino acid, is typically the limiting amino acid in pulses (legumes), not in cereals like wheat. Cereals are a relatively good source of methionine.
Option D: Cystine is another sulfur-containing amino acid. Like methionine, it is more commonly deficient in pulses and legumes, not in cereals.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Limiting amino acids in staple foods as background academic context rather than a clinical decision trigger.
Understanding limiting amino acids is crucial for providing dietary advice, especially for vegetarian or vegan patients, to prevent protein-energy malnutrition.
Nurses can educate patients on the importance of combining foods, like cereals and pulses (e.g., roti and dal), to achieve a complete protein profile for tissue growth and repair.
This knowledge is vital in community health for planning nutritional programs and addressing dietary deficiencies in populations reliant on staple grains.

How to Approach the Question

First, identify the food item in the question: 'wheat'.
Classify the food item into its major food group. Wheat is a 'cereal'.
Recall the nutritional characteristics of that food group. Specifically, remember the concept of 'limiting amino acids' for major staples.
Recall that cereals are generally deficient in the essential amino acid Lysine.
Evaluate the options. Lysine is present as an option. The other options (Methionine, Cystine) are limiting in pulses, and Leucine is abundant in cereals. Therefore, Lysine is the correct answer.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 162-164

Practise the full HPSSC Staff Nurse - 2021

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