Calcium is the most abundant mineral in the body. It is well known for its important role in maintaining strong teeth and bones. Calcium requires vitamin D for absorption. It also works closely with magnesium, zinc, fluoride and phosphorus.
Calcium is also important for proper heart function, nerve transmission, and blood clotting.
Complex processes control the amount of calcium in the blood. When there is too little of it in the blood, hormones pull it from the bones to meet the body's demands. Dairy products are the most concentrated source of calcium. Dark green leafy vegetables and fish with edible bones are also good sources. Many breakfast cereals and orange juice brands are fortified with calcium.