Calcium has several important functions - including helping to build strong bones and teeth and making sure blood clots normally. It is also thought that calcium may help lower high blood pressure and protect against colon and breast cancer.

Good sources of calcium include:

• milk, cheese and other dairy foods
• green leafy vegetables, such as broccoli, cabbage and okra (but not spinach)
• soya beans
• tofu
• soya drinks with added calcium
• nuts
• bread and anything made with fortified flour
• fish where you eat the bones (such as sardines and pilchards)

Adults need 700mg of calcium a day.

You should be able to get all the calcium you need from your daily diet.

Taking high doses of calcium could lead to stomach pain and diarrhoea.