Calcium & Bone Health

Why is calcium important?

Calcium is essential for building and maintaining healthy bones throughout life. Calcium combines with other minerals to form hard crystals giving bones strength and structure. Almost 99% of the body’s calcium is found in the bones.

A small amount of calcium is absorbed into the blood and used for the healthy functioning of the heart, muscles, blood and nerves. Bones act like a calcium bank. If there is not enough calcium in your diet, the body will take what is needed from your bones for use in other parts of the body. If this happens, your bone density (bone strength) will gradually decline, and you may be at risk of developing osteoporosis.

How much calcium is recommended?

Australian dietary calcium recommendations vary according to age.

LifestageAgeRecommended IntakeGuidance
Children1-3 years500 mg per dayGrowing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Children4-8 years700 mg per dayGrowing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Girls & Boys9-11 years1,000 mg per dayGrowing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Teenagers Girls & Boys12-18 years1,300 mg per dayAdequate calcium intake maintains bone strength.
Adults19 years +1,000 mg per dayAdequate calcium intake maintains bone strength.
Older AdultsWomen 50 years +1,300 mg per dayThe daily recommendation increases as calcium is less effectively absorbed from the intestine, and more can be lost through the kidneys..
Older AdultsMen 70 years +1,300 mg per dayThe daily recommendation increases as calcium is less effectively absorbed from the intestine, and more can be lost through the kidneys.

Excessive calcium intake is not recommended. If calcium supplementation is used, it should only form part of daily requirements.

Calcium and food

Eating a calcium-rich diet is the best way to achieve recommended calcium intake. Calcium content in food varies, so it is important to consume ‘calcium-rich’ foods. Half of all Australian adults do not achieve their daily recommended calcium intake. Adding calcium to your diet is easy by focusing on food groups with higher calcium levels.

Calcium-rich foods examples including leafy veg, dairy, fish, grains & nuts.
Calcium-rich foods examples
Food typeExamplesCalcium range (mg per serve)
DairyMilk, cheese, yogurt150 – 305 mg per serve
SeafoodTrout, snapper, mussels, oysters, prawns, canned sardines or salmon35 – 300 mg per serve
VegetablesCucumber, kale, silverbeet, Chinese cabbage, broccoli rocket, watercress, bok choy, leeks59 – 250 mg per serve
Nuts & seedAlmonds, brazil nuts, hazelnuts, walnuts, sesame seeds, tahini paste28 – 75 mg per serve
FruitsOrange, strawberries, figs, kiwi fruit, dates16 – 95 mg per serve
OtherEggs, calcium-set tofu, canned chickpeas or soybean21 – 105 mg per serve
MeatPork chop, chicken21 – 105 mg per serve

Do we absorb all the calcium we eat?

Not all the calcium we consume is absorbed. A small amount of calcium will be lost and excreted from the normal body. This is factored into the recommended intake for your age.

Other factors can impact calcium absorption and should be discussed with your doctor, for example:

  • Low vitamin D levels
  • Excessive caffeine and alcohol intake
  • Certain medical conditions (for example, coeliac disease, kidney disease)

Calcium supplements

It is best to obtain calcium from your diet. However, when adequate calcium intake is not possible, a supplement may be required as directed by your doctor or pharmacist. Healthy Bones Australia recommends 500-600 mg of supplement doses daily when required. This is considered safe and effective.

The most common calcium supplements are calcium carbonate, calcium citrate or hydroxyapatite. Supplements are available as oral tablets, effervescent tablets or soluble powder. Calcium supplements are usually well tolerated.

Calcium supplements are sometimes combined with vitamin D, as adequate vitamin D levels are important to assist the absorption of calcium in the body. Take supplements as directed, and talk to your doctor or pharmacist if you have any queries.

Diagnosed osteoporosis and calcium.

Calcium is essential for supporting your bone health. For people with diagnosed osteoporosis, calcium alone is not sufficient. Osteoporosis medication is generally required as directed by your doctor. It is common practice for doctors to prescribe calcium supplementation to accompany osteoporosis medication. Adequate calcium intake throughout adult life helps support bone health but may not prevent osteoporosis, as other factors can negatively impact bone health. See risk factors.

Questions and answers about calcium.

Why is calcium important for bones? How does it help my bones?

Calcium is stored in bones and helps give bone strength. Your body also needs calcium for other functions, so you will take calcium from the bones when your calcium intake is low. Adults unable to eat enough calcium may require a limited supplement to help top up calcium levels.

Why am I losing calcium? Can I rebuild bone strength?

You can lose calcium if you are not consuming enough daily calcium in your diet and your body takes what it needs from your bone storage. Also, when your vitamin D is low, you are not absorbing the calcium you eat.
You can rebuild bone strength by improving your diet, exercising and stopping negative factors.

What foods are high in calcium, and which are best for bones?

The foods high in calcium and best for bones include dairy (milk, cheese, yogurt), vegetables cucumber, kale, silverbeet, Chinese cabbage, broccoli, rocket, watercress, bok choy, leeks), seafood (trout, snapper, mussels, oysters, prawns, canned sardines or salmon) nuts & seeds (almonds, brazil nuts, hazelnuts, walnuts, sesame seeds, tahini paste) fruits (orange, strawberries, figs, kiwi fruit, dates) and other items such as eggs, calcium set tofu, canned chickpeas, soybeans. Even some meat (pork chop, chicken).