Vitamin D helps in the absorption of?

Appeared in: DSSSB - 29 August 2019 (Shift-2)

Explanation

Vitamin D is essential for regulating calcium and phosphate metabolism.
Its active form, calcitriol [1,25(OH)₂D], directly promotes the absorption of calcium from the small intestine.
Calcitriol achieves this by stimulating the production of calcium-binding proteins (like calbindin) within intestinal cells, which actively transport calcium into the blood.
This mechanism is vital for maintaining adequate serum calcium levels, which are necessary for bone mineralization, nerve function, and muscle contraction.

Option A: Sodium absorption and balance are primarily regulated by the renin-angiotensin-aldosterone system (RAAS) and renal function, not by vitamin D.
Option C: Potassium balance is mainly controlled by the kidneys under the influence of aldosterone. Its absorption in the gut is largely passive and not dependent on vitamin D.
Option D: Manganese is a trace mineral, and its absorption is not directly regulated by vitamin D. Its uptake can be influenced by the presence of other minerals like iron and calcium.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Role of Vitamin D in mineral absorption as background academic context rather than a clinical decision trigger.
Nurses play a key role in educating patients about sources of Vitamin D, including sensible sun exposure, fortified foods (milk, cereals), and fatty fish, to prevent deficiency.
At-risk populations for Vitamin D deficiency include the elderly, individuals with limited sun exposure, people with darker skin pigmentation, and patients with malabsorption syndromes or chronic kidney disease.
Monitoring serum 25(OH)D levels is crucial in at-risk patients to guide supplementation and prevent complications like osteomalacia and osteoporosis.

How to Approach the Question

First, identify the core of the question. It asks about the primary function of Vitamin D in relation to mineral absorption.
Recall the major physiological roles of key vitamins. Vitamin D is widely known for its connection to bone health.
Connect bone health to its primary mineral component, which is calcium.
Evaluate the options. Vitamin D's main endocrine function is to regulate calcium and phosphate homeostasis. The other minerals listed (sodium, potassium, manganese) are regulated by different pathways.
Select the option that represents the most direct and significant role of Vitamin D in mineral metabolism.

Concept Tested & Keywords

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E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 2188-2190

E6 Harper's Illustrated Biochemistry2023 (pp 26-793 of 813) p. 532-534

E6 Medicine Harrison 22e Part 2 p. 1205-1207

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