All are true regarding vitamin A, except?

NCL (MP) Nursing Officer - 2019

Applied Nutrition & Dietetics

Hard

Appeared in: NCL (MP) Nursing Officer - 2019

Explanation

The statement that vitamin A supplementation reduces mortality in diarrhea is the exception.
While vitamin A deficiency is linked to an increased risk of death from diarrhea, and supplementation can reduce the incidence and severity of diarrheal episodes, the evidence for a direct reduction in mortality is less consistent compared to its effect on measles.
The impact on measles mortality is a cornerstone of public health policy, whereas the benefit for diarrhea mortality is considered part of a broader improvement in child health rather than a specific, standalone effect of the same magnitude.

Option A: This statement is true. Green leafy vegetables are a primary source of provitamin A carotenoids, which the body converts to vitamin A.
Option B: This statement is true. High doses of preformed vitamin A (retinol), especially during the first trimester of pregnancy, are known to be teratogenic, causing potential birth defects.
Option C: This statement is true. High-dose vitamin A supplementation is a standard and highly effective WHO-recommended treatment for children with measles to significantly reduce mortality and complications.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The question tests knowledge of the physiological roles, sources, and clinical applications of Vitamin A, specifically focusing on identifying a statement that is not universally accepted as true as background academic context rather than a clinical decision trigger.
Nurses play a vital role in nutritional counseling and administering supplements. Understanding the nuances of vitamin A is critical for patient education, especially for pregnant women (risk of teratogenicity) and in pediatric care (measles treatment).
A key nursing responsibility is to differentiate between dietary sources. A nurse would reassure a patient that eating plenty of carrots and spinach is safe, but taking high-dose vitamin A pills without medical advice can be dangerous.
What if? If a child with measles also has clinical signs of vitamin A deficiency (like Bitot's spots on the eyes), a third dose of vitamin A is administered 4 to 6 weeks later, in addition to the initial two doses, to replenish their stores.

How to Approach the Question

First, identify the question type. This is a negative-framed question using the keyword 'except', which means you must find the one false or least accurate statement among the four options.
Read each option carefully and evaluate its factual accuracy based on your knowledge of vitamin A.
Option A: Recall the dietary sources of vitamin A. Green leafy vegetables are known sources of beta-carotene (provitamin A). This is likely true.
Option B: Consider the safety of vitamins in pregnancy. High doses of fat-soluble vitamins, particularly vitamin A, are known teratogens. This is likely true.
Option C: Think about public health interventions for childhood diseases. Vitamin A for measles is a classic, highly effective intervention to reduce mortality. This is likely true.
Option D: Evaluate the role of vitamin A in diarrhea. While it supports gut immunity, compare the strength of evidence for reducing mortality from diarrhea versus measles. The effect on measles is more direct and pronounced.

Concept Tested & Keywords

Concept Tested: The question tests knowledge of the physiological roles, sources, and clinical applications of Vitamin A, specifically focusing on identifying a statement that is not universally accepted as true.
Stem keywords: vitamin A, true, except
Lead-in keywords: except
Negative lead-in flag: except

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E6 Medicine Harrison 22e Part 2 pp. 516-518, 515-517

E6 Obstetrics Williams p. 81-95