Calcium deficiency may cause which of the following symptoms?

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

Answer: (C)

Calcium deficiency makes nerves and muscles more easily excited, because low calcium lowers the threshold for electrical activity in cell membranes. When extracellular calcium is reduced, nerve and muscle membranes become unstable and more likely to depolarize, leading to increased neuromuscular excitability. That heightened excitability can produce tingling, muscle cramps, and muscle twitching, and in severe cases it can progress to convulsions. So convulsions are a possible consequence of calcium deficiency due to this amplified electrical activity in the nervous system.

Iron deficiency, by contrast, mainly causes anemia and fatigue. Magnesium deficiency can cause its own neuromuscular symptoms but is a separate issue from calcium deficiency. Vitamin D deficiency affects bone health and calcium metabolism, but the specific symptom listed here points to the direct consequences of low calcium on nerve and muscle excitability.