Many different nutrients are required for the growth, development and maintenance of healthy bones. These nutrients include: Calcium, vitamin D, phosphorous, magnesium and protein.
Calcium is particularly important for bone development. At birth the skeleton has only 20-30 g of calcium and approximately 150 mg of calcium is deposited in the bones each day until the age of about 20.
The average adult skeleton will have an average of 1200mg of calcium within it which means that a lot of calcium is required throughout life in order to build strong bones. As the body cannot make calcium, it is essential that sufficient amounts are taken in from the diet.
If calcium intake is insufficient when bones are growing and developing, they may never reach full strength or peak bone mass which is usually reached at around 30-35 years of age.
For 11 to 18 year olds, about 1 in 17 boys and 1 in 9 girls have a calcium intake below the LRNI.
Vitamin D is also essential for bone health. We get most of our vitamin D from the action of sunlight on our skin but it is also found in oily fish, fish oils such as cod liver oil, meat (particularly liver), eggs and dairy products.
Our bodies contain a precursor of vitamin D which is converted into active vitamin D when we are exposed to sunlight.
Vitamin D increases the absorption of calcium from foods, which helps to provide more calcium for building bones.
In the past many children developed rickets as they lacked vitamin D and although the prevalence has declined, cases do still occur among some Asian groups in the UK and it is beginning to re-emerge as a problem in other population groups.
Phosphorous, magnesium and protein are also important for building the bone tissue.
What other factors are involved in good bone health?
Diet is not the only important factor in ensuring bones develop correctly.
Genetic factors are sometimes involved i.e. some ethnic groups may have stronger bones than others.
Gender is also important as women tend to have a lower bone mass than men.
Physical activity, especially weight bearing exercises such as walking and running are very important to build bone strength.
Body weight affects bone strength, as heavier people tend to have stronger bones due to the extra weight they are required to carry.
Hormones are involved as irregular menstrual periods and menpause can cause bone loss.