Calcium is also used by almost every cell in the body including the heart and nerves and is necessary for muscle contraction and for the development and maintenance of bone structure and is an important component of a healthy diet. Although we imagine our bones are permanent, they are actually being constantly renewed throughout our life and replaced with new bone tissue. In fact, our entire skeleton is renewed approximately every seven years. If we do not consume enough calcium in our diet, our body takes the necessary calcium from our bones to use for other essential functions. This can result in brittle or porous bones, broken bones, low bone density and weakness - especially in later life.