Second, hypocalcemia has to do with low levels of calcium within the blood. Whereas dietary calcium deficiency is a result of low nutritional intake, hypocalcemia is usually caused by certain medications or even medical conditions like hypoparathyroidism. Hypocalcemia is particularly concerning as the body will readily pull calcium from the bones in the event of a blood calcium deficiency in orders to support the proper function of the brain, heart, nerves, and muscles.