Which statement correctly describes the primary roles of vitamin A and common deficiency signs?

Which statement correctly describes the primary roles of vitamin A and common deficiency signs?

• A. Vitamin A is primarily involved in bone formation and calcium regulation.
• B. Vision (retina), immune function, and cell differentiation; deficiency can cause night blindness and conjunctival xerosis.
• C. Vitamin A is only involved in energy metabolism.
• D. Vitamin A deficiency never affects the eyes.

Answer: (B)

Vitamin A has key roles in maintaining vision, supporting immune function, and guiding the differentiation of epithelial cells. In the retina, the active form of vitamin A is part of visual pigments like rhodopsin, which is essential for adapting to low light. This links directly to night vision: when vitamin A is deficient, night blindness is one of the first signs. Vitamin A also helps keep mucosal and epithelial surfaces healthy, which is why deficiency can compromise immunity and surface tissues, including the conjunctiva of the eye. Conjunctival xerosis, a dryness and roughening of the conjunctiva, is another classic sign of deficiency, along with other ocular changes that can progress if the deficiency isn’t corrected. In contrast, bones and calcium regulation are mainly influenced by vitamin D and related minerals, so stating that vitamin A is primarily involved in bone formation misplaces its major roles. Saying vitamin A is only involved in energy metabolism ignores its critical non-energy functions in vision and tissue differentiation. And asserting that vitamin A deficiency never affects the eyes contradicts well-established signs like night blindness and conjunctival changes.

Vitamin A has key roles in maintaining vision, supporting immune function, and guiding the differentiation of epithelial cells. In the retina, the active form of vitamin A is part of visual pigments like rhodopsin, which is essential for adapting to low light. This links directly to night vision: when vitamin A is deficient, night blindness is one of the first signs. Vitamin A also helps keep mucosal and epithelial surfaces healthy, which is why deficiency can compromise immunity and surface tissues, including the conjunctiva of the eye. Conjunctival xerosis, a dryness and roughening of the conjunctiva, is another classic sign of deficiency, along with other ocular changes that can progress if the deficiency isn’t corrected.

In contrast, bones and calcium regulation are mainly influenced by vitamin D and related minerals, so stating that vitamin A is primarily involved in bone formation misplaces its major roles. Saying vitamin A is only involved in energy metabolism ignores its critical non-energy functions in vision and tissue differentiation. And asserting that vitamin A deficiency never affects the eyes contradicts well-established signs like night blindness and conjunctival changes.