Sunshine! Vitamin D, calcium and bone health

Bone mass starts to build up from birth until the mid-twenties when the peak mass is reached. Thereafter it levels out and then declines with age. The rate of decline is also dependant on diet, smoking, physical activity and hormonal changes, such as post-menopause where the decline in oestrogen levels causes bone loss.

Vitamin D supports the absorption of calcium and helps to maintain the right ratio of minerals in the blood. Calcium is an essential mineral for giving bones strength; both Calcium and Vitamin D work together and are considered to have the strongest effect on bone health when used in combination. Although these are the two most researched nutrients for bone health, phosphorus, zinc, magnesium, manganese and Vitamin K are also important for bone health - hence a varied diet is required to ensure these nutrients are also included.

The recent National Diet and Nutrition Survey found that just under 4% of men and 8% of women (mainly teenagers) had inadequate calcium intake and that Vitamin D intake was inadequate in around 19% of women and 17% of men.

Most Vitamin D is sourced from the summer sunshine and about 15 minutes exposure to the sunshine (during summer months) is about the time needed to receive enough Vitamin D for the skin to make. However the use of sun creams, long working hours indoors and being overweight or obese hinders the exposure or the ability for the skin to respond.

Foods rich in calcium such as dairy foods are also rich in Vitamin D and other nutrients for bone health, particularly protein and phosphorus, so the combination of these nutrients provides an ideal recipe. However eating foods that are rich in Vitamin D such as oily fish and eggs and combining these with calcium rich foods such as green leafy vegetables, nuts, seeds and dried fruit (particularly figs) are useful for people who don't or are unable to eat dairy foods.

In addition, fortified foods are handy to top up requirements. Dairy alternatives are often fortified with calcium and Vitamin D - check the label and particularly look out for Vitamin D3 rather than Vitamin D2. Vitamin D3 being the active form and more effective.

Although regular summer sun exposure is key to topping up on Vitamin D levels (after 15 minutes precautions should be taken to prevent sunburn), incorporating natural sources of Vitamin D and calcium - which can also provide other nutrients for bone health - fortified foods can also help contribute bridging the gap.

In addition, weight bearing exercises can also support bone health and other positive lifestyle factors such as not smoking or limiting alcohol, that is, not beyond the recommended limits (14 units for women and 21 units for men a week).