Calcium rarely makes headlines until something goes wrong — a fracture from a minor fall, nagging muscle cramps, or a bone-density scan that comes back low. Yet calcium quietly underpins your bones, teeth, muscles and nerves every single day, and a long-running shortfall can do real damage before you notice. It's one of the key minerals in our vitamin and mineral deficiencies guide.
Why your body needs calcium
About 99% of your body's calcium is stored in your bones and teeth, giving them strength. The rest plays a vital role in muscle contraction, nerve signalling, and blood clotting. Here's the catch: if your diet runs short, your body pulls calcium out of your bones to keep blood levels steady — so your blood test can look normal while your bones slowly weaken. That's why calcium deficiency is often silent until osteoporosis shows up years later.
Symptoms of calcium deficiency
Early on there may be no symptoms. As it progresses, watch for: