Milk. Udderly important for your health. 

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.

How much should I take?

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).

What are the sources of calcium?

In Australia, the major food sources of calcium are dairy products — milk, yoghurt, cheese and ice cream. Generally speaking, low-fat dairy products have just as much calcium as regular versions, so you don't miss out on calcium if you're cutting back on fat. Dairy products are the best calcium source, but not the only one. If you need to avoid or prefer not to eat them, there are calcium-enriched non-dairy alternatives.

If you're concerned about how much calcium you eat, you may find it useful to talk to a dietitian about ways to increase calcium in your diet, and check out tips for boosting your calcium intake.

Is there anything I should avoid?

Some substances can reduce your body's ability to make use of calcium. To get the most from calcium in food (or supplements) it's best to avoid having the following things at the same time as food rich in calcium. This won't always be possible, especially if you're vegetarian:

• Oxalates - in spinach, rhubarb, peanuts.
• Phytates - in beans, peas and lentils, and in minimally processed wholegrain and wholemeal cereals.
• Large amounts of fibre.
• Some medications, such as cholestryramine (for treating high cholesterol) and antacids that contain aluminium, can interfere with calcium absorption if taken at the same time. Conversely, taking calcium supplements or eating calcium-rich foods at the same time as some other medications can reduce the effectiveness of the medication -- for example, tetracycline for infections, beta blockers for heart conditions and even the common aspirin tablet.
• Some other minerals (such as iron) tend to compete with calcium for absorption. If you need both iron and calcium supplements it's best to take them at different times of the day.
• Caffeine can also increase your body's calcium needs - but if you get lots of calcium from your diet, caffeine may only have a minor effect. Adding milk to coffee may go part or all of the way to balancing out the effects of the caffeine it contains. 

What are some useful tips to boost my calcium intake?

• Include at least 3 serves of dairy products in your diet each day. This could include milk on your cereal or as a smoothie, a tub of yoghurt and a piece of cheese.
• Snack on almonds during the day - not only will it boost your calcium intake but nuts have many other proven health benefits, including being good for your heart.
• Have a salmon sandwich for lunch a few times a week with salad.
• Choose calcium-enriched foods where possible.
• Stay active, with regular weight bearing exercise.
• Maintain a healthy weight, rather than aiming to be too thin.
• Limit the amount of salt you eat, particularly from highly salted processed foods.
• Don't smoke.
• Avoid too much alcohol.
• Consider a calcium supplement if it's not feasible to get the calcium you need from your diet.
• If you're a woman who is experiencing menopause, you may want to consider discussing hormone replacement therapy with your doctor.