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.

Lifestage	Age	Recommended Intake	Guidance
Children	1-3 years	500 mg per day	Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Children	4-8 years	700 mg per day	Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Girls & Boys	9-11 years	1,000 mg per day	Growing bones require daily calcium intake. Daily dietary recommendations increase as children grow.
Teenagers Girls & Boys	12-18 years	1,300 mg per day	The daily recommendation increases as calcium is less effectively absorbed from the intestine, and more can be lost through the kidneys.
Adults	19 years +	1,000 mg per day	Adequate calcium intake maintains bone strength.
Older Adults	Women 50 years +	1,300 mg per day	Calcium is essential during the growth spurt. Peak bone mass is achieved by the early twenties, and 40% is acquired during puberty.
Older Adults	Men 70 years +	1,300 mg per day	Calcium is essential during the growth spurt. Peak bone mass is achieved by early twenties, and 40% is acquired during puberty.

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.

Food type	Examples	Calcium range (mg per serve)
Dairy	Milk, cheese, yogurt	150 – 305 mg per serve
Seafood	Trout, snapper, mussels, oysters, prawns, canned sardines or salmon	35 – 300 mg per serve
Vegetables	Cucumber, kale, silverbeet, Chinese cabbage, broccoli rocket, watercress, bok choy, leeks	59 – 250 mg per serve
Nuts & seed	Almonds, brazil nuts, hazelnuts, walnuts, sesame seeds, tahini paste	28 – 75 mg per serve
Fruits	Orange, strawberries, figs, kiwi fruit, dates	16 – 95 mg per serve
Other	Eggs, calcium-set tofu, canned chickpeas or soybean	21 – 105 mg per serve
Meat	Pork chop, chicken	21 – 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.