Which deficiency is characterized by muscle weakness or trembling and hyperactive reflexes?

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

Answer: (D)

Magnesium helps keep nerves and muscles from becoming too excitable by regulating calcium flow and supporting energy production for muscle contraction. When magnesium is low, nerve and muscle cells become more easily activated, leading to tremors, weakness, and reflexes that are unusually responsive. That combination of muscle weakness with tremors and hyperactive reflexes points to magnesium deficiency most clearly. Iron deficiency mainly causes fatigue from anemia; calcium deficiency tends to produce cramps or tingling and sometimes tetany, not the same pattern of hyperactive reflexes; vitamin D deficiency affects bone health and can cause generalized weakness but not the characteristic neuromuscular irritability seen with low magnesium.