Our bones are complex living tissue comprised of a thick outer shell (known as the cortex) and a strong inner honeycomb mesh of tiny cross-members (known as the trabeculae). This structure enables our bones to be strong, lightweight and somewhat flexible. These properties are important because they allow our skeletons to support us while being able to cope with the stresses and strains that we impose upon them in the course of day-to-day life. During the first two decades of life our skeleton grows, reaching what is termed Peak Bone Mass – the point when our bones are at their most dense – in our early 20s mentions. In the middle period of life, a continual process of repair is ongoing which ensures that old worn-out bone is replaced by fresh new bone. In later life or when specific medical conditions occur in people in their middle years – the balance between old bone being broken down (known as resorption) and new bone being made (known as formation) can be lost. When there is more resorption than formation, the total amount of bone in the skeleton begins to decline and bones become more fragile. This is particularly common for women who have experienced the menopause because oestrogen plays an important role in maintaining the balancing act of this process known as bone remodeling. For significant numbers of men it should be noted that, after 70 years of age, loss of bone density is also an issue. When a person’s bone density drops below a specific level a diagnosis of osteoporosis will be made. Treatment of osteoporosis Calcium Calcium is an important component of bone. Therefore, it is important that we eat sufficient calcium to maintain our skeletons, but there is no evidence that taking more than this is helpful. There is controversy regarding what is an adequate intake, recent evidence suggesting that as little as 500 mg/day (2 servings of dairy products) is sufficient in adults, though some experts still recommend 1000 mg/day, or more. Many older people find it difficult to take 1000 mg/day in their diets, so use supplements. However, there are now several safety concerns related to calcium supplements, and the consensus is that calcium from the diet is to be preferred. People ingesting at least 2 servings of dairy products daily are likely to be receiving enough calcium. Vitamin D Vitamin D is a substance made in the skin as a result of sunlight exposure. It facilitates absorption of calcium from the diet. When vitamin D levels are very low, mineralisation of bone is impaired. Individuals who never go outside (e.g. frail elderly), those who are veiled, and those who have dark skin are at risk of vitamin D deficiency, so might benefit from a vitamin D supplement. The use of supplements by those who are not deficient does not improve bone health. Most healthy European New Zealand adults living independently do not require vitamin D supplements.