Our bones are basically the structural framework of our bodies – without them we would not be able to stand up and move around. They also serve to protect other systems such as our internal organs.
A bit of bone biology
Bones are made up of connective tissue, with most also containing bone marrow where blood cells are made. The human body has over 200 bones, which together with the muscles and joints,form the musculoskeletal system.
The main skeletal areas include the skull, spine, chest, arms, hands, pelvis, legs and the feet. There are also several types of bone in our bodies – including long, short, flat and irregular.
Contrary to how it might seem, bone is not ‘fixed’ but is continuously being broken down and reformed. Peak bone mass is usually achieved by about age 30, and as we age, more bone tends to be broken down than remade.
Certain types of cells are involved in this process. Bone-forming cells are called osteoblasts. They produce a matrix that becomes mineralised, creating a new layer of bone tissue and increasing the density of the bones. Osteoclasts on the other hand dissolve bone mineral, releasing calcium into the bloodstream for use by the body. When the rate of breakdown is higher than that of formation, bone density reduces and the bones may become more brittle.
The problem of bone loss
The latest Australian Bureau of Statistics (ABS) National Health Survey reveals that around 3.5% of the population has osteoporosis (thinning of the bones). The Australian Institute of Health and Welfare (AIHW) also states that about 10% of people over 50 have the condition. Osteoporosis causes bones to become thin and fragile and prone to easily breaking and fracturing. Nearly twice as many women as men have the condition.
A fall in estrogen after menopause in particular can lead to accelerated bone loss in women. According to the Better Health Channel, other risk factors for osteoporosis include low levels of Vitamin D and dietary calcium, excess alcohol and / or caffeine, smoking, lack of physical activity, and certain conditions and medications.
How to maintain bone health
While we are more likely to lose bone as we age, there are things we can do to help keep our bones in good health. These include:
- Sufficient dietary calcium – this prevents calcium leaching from bones. Sources include dairy, almonds, seeds, salmon, green vegetables and calcium-fortified foods. If dietary levels are too low, supplements may be beneficial.
- Vitamin D – assists with the absorption of calcium. The best sources are sunshine, supplements, and Vitamin-D fortified foods. Sun exposure also needs to be balanced with taking precautions to protect against skin cancer.
- Healthy overall diet – one that includes plenty of plant food and wholegrains.
- Regular exercise – especially weight-bearing exercise and strength-training.
- Other – limiting alcohol and caffeine and quitting smoking if necessary.
According to the Better Health Channel, the best way to measure bone density is through a specialised bone-density scan.
Bone conditions such as osteoporosis can have a major impact on your health and mobility, especially as you age. But there are ways to look after your bones, so they stay healthy and strong.
Our bones are continually being broken down and rebuilt. Read about how this works and how to maintain bone health in our latest article.