Up to early adulthood your body is building up the calcium in your bones. As you grow older, gradual calcium loss from your bones is inevitable - but there are things you can do to slow it down.
Women are behind the eight-ball in terms of calcium loss. They start out with less bone mass than men, and during and after menopause they produce less of the hormone oestrogen, which normally helps to keep calcium in their bones.
That's why women are much more at risk later in life of developing osteoporosis - thin, weak bones which fracture more easily. It's estimated that half of all women and a third of all men over 60 will suffer a bone fracture due to osteoporosis.
Please note: this information was current as of April 2005 but is still a useful guide today.
The amount of calcium you should aim for depends on your sex and the stage you're at in life. Children and teenagers need more to build up their calcium stores and strengthen growing bones. Women during pregnancy and when breastfeeding need extra calcium to provide for the needs of their child.
The National Health and Medical Research Council (NHMRC) has set recommended daily intakes - a daily target - for calcium. These were last revised in 1985 and are being looked at again now. Some scientists are suggesting they should include a much higher calcium intake for women, especially after menopause. For these women, a higher calcium intake, from both food and supplements, has been shown to slow the rate of bone loss and reduce the risk of fractures.
According to a 1996 Consensus Conference of Australian experts on the prevention of osteoporosis, a woman should aim for about 1500 mg of calcium per day after menopause (unless she's taking hormone replacement therapy (HRT) or some other therapy to reduce bone loss).