Night blindness and poor growth are symptoms of deficiency in which nutrient?

• A. Vitamin A deficiency
• B. Vitamin D deficiency
• C. Iron deficiency
• D. Calcium deficiency

Answer: (A)

Night vision functioning and growth rely on vitamin A. In the retina, vitamin A is converted to retinal, a component of rhodopsin, which is essential for sensing light and adjusting to low-light conditions. When vitamin A is deficient, rhodopsin can't be regenerated quickly enough, leading to night blindness. In children, vitamin A also supports healthy epithelial tissues and overall growth, so deficiency often shows up as poor growth. The other deficiencies affect different systems—Vitamin D mainly causes bone problems like rickets, iron deficiency leads to anemia and fatigue, and calcium deficiency affects bones and muscles—so night blindness is not a typical sign of those.