Bone health and HIV disease

February 2008     View PDF     En español

What is bone?

Bone is living tissue and is in constant change during your life. It’s made of several materials, mainly collagen and minerals. Collagen gives your bones a soft flexible framework. The minerals, like calcium and phosphorus, help harden the framework for strength. Vitamin D is also important, as it helps the body absorb calcium and slows the kidneys from removing it. Together these materials help bones withstand stress. Bone also has an outer layer of nerves and small blood vessels.

To keep bones healthy, your body removes old bone (bone resorption) as it adds new bone (bone formation). The peak bone mass usually occurs around age 30. After that, bone density naturally declines over time. The ageing process can remove more bone tissue than it replaces—making it less dense, weaker and more prone to injury. Having the right amount of minerals in your body as well as good bone formation and resorption will help maintain healthy bones.