How are bones strengthened?

The bones of the skeleton provide structural support for the body, allow for movement and protect our internal organs. Each bone is made from living tissue and is continuously being rebuilt throughout life. This includes the removal of old, damaged bone tissue and its replacement with new, stronger bone.1 So, if bone is constantly being remade, what are the factors involved in making them strong and healthy?

Bone reacts to mechanical stress (weight bearing movement) by changing size and shape. Bone tissue is added in areas of high mechanical stress, which increases the strength of bone and therefore its resistance to fractures.2 This is why exercise is such an important part of maintaining healthy, strong bones. Weight bearing exercises such as walking, jogging, dancing, and muscle strength training such as lifting weights, place mechanical stress on the bones, causing them to become stronger. During childhood and adolescence, exercise helps build up maximum bone strength. In adulthood, it promotes the maintenance of muscle and bone strength and in older adults it reduces bone loss.3

A healthy well‐balanced diet is also needed. The amount of minerals such as calcium and phosphorous4 found in bone is another important factor in their strength. Other nutrients that play important roles in supporting bone health include vitamin D, vitamin K, boron, magnesium and manganese.

In addition to nutritional status and exercise levels, the degree of bone mineralisation in an individual also depends on hormonal factors and age. As we age, our bones tend to lose mass, making them more likely to fracture. Women tend to have a lower bone mineral content than men and this gap widens with aging. Women also tend to lose more bone mass after menopause, due to a lack of oestrogen.5 Reaching maximum bone density during our adolescence and maintaining it during adulthood is beneficial in our later years when some bone loss is inevitable.