Osteoporosis: Understanding Bone Loss

A balanced system supports the body

The body is always losing (resorbing) and making bone. This process is called remodeling. Bone-resorbing cells take bone apart. They do this so the minerals can be used to repair an injury or make new bone. Bone-making cells form new bone using calcium and other minerals. These minerals come from the food you eat. When this bone-making system is in balance, the same amount of bone is built and resorbed.

Diagram of normal bone growth showing three different types of bone cells.

A balanced system keeps building and resorbing bone.

An unbalanced system can't give support

Changes in hormone levels, activity, medicines, or diet can affect the bone-making system. When the system gets out of balance, the amount of bone lost is greater than the amount of bone made. This can cause osteopenia. It is when bone starts to become less dense. Left untreated, bone loss gets worse, leading to osteoporosis. Weak bones can’t support the body. In fact, they can break (fracture) just from the weight of your body. This often happens in bones of the spine (vertebrae). When vertebrae fracture, parts of the spine compress. This causes the back to bend or hump over, and it can also cause back pain.