Calcium is well known as a requirement for strong bones and teeth, but what else do we need this mineral for?
Only 20% of Australians achieve the recommended intake for calcium. So, is eating calcium-rich foods enough?
Key Facts about calcium
- 2% of an adult human’s body weight is due to calcium.
- Most of this mineral is stored in bones and teeth.
- Vital for strengthening bones and teeth.
- Plays a role in muscle contraction and relaxation.
- Assists the regulation of our heartbeat.
- Aids blood clotting.
- Important for transmitting messages through our nervous system.
- Supports enzyme function.
|Food||Serve Size||Calcium (mg)*|
|Skim milk||1 Cup (250ml)||341|
|Regular milk||1 Cup (250ml)||304|
|Regular soy milk calcium fortified||1 Cup (250ml)||300|
|Rice milk calcium fortified||1 Cup (250ml)||275|
|Regular natural yoghurt||200g||386|
|Cheddar cheese||1 slice (21g)||160|
|Camembert||I wedge (25g)||121|
|Sardines in water, no added salt||90g||486|
|Pink salmon, canned in water, no added salt||90g||279|
|Snapper, grilled, with olive oil||100g||163|
|Tahini||1 tablespoon (60g)||66|
|Almonds with skin||30 almonds (36g)||90|
|Brazil nuts||10 (35g)||53|
|Curley leaf parsley, chopped||1 tablespoon (5g)||12|
|Silverbeet, boiled||½ cup (100g)||87|
|Chickpeas, canned||1 cup (200g)||90|
|2 boiled eggs||Medium||42|
*Source NUTAB 2010
- Bioavailability (efficiency of absorption) varies across foods.
- Oxalate (found in green leafy vegetables, rhubarb) and phytic acid (present in seeds, nuts, grains, raw bean) lower the absorption of calcium.
- Vegans and lactovegetarians can attain calcium balance by eating calcium-rich foods.
- Bioavailability of supplements depends on the dosage and whether they are taken with a meal.
- Once the absorption mechanism in our gut is saturated, only 5-10% of additional calcium is absorbed.
- High sodium and protein intakes, that are above the recommendations, increase calcium losses in the urine.
Vegans and lactovegetarians can attain calcium balance by eating calcium-rich foods.
Calcium requirements change during our lifetime.
Please see the recommended intakes for calcium here
Dairy foods are considered calcium-rich foods. See the recommended intakes of dairy foods for adults here.
When calcium levels are low in the blood, the body releases hormones to reduce the amount excreted in the urine.
If absorption from the gut is insufficient, calcium is removed from the bones. If calcium intake remains low for a period of time, the bones become weak and brittle.
Osteoporosis develops when the loss of minerals from the bones occurs at a great rate to their replacement. This causes the bones to become thin and fragile.
Bone health and calcium
- Bone mass increases sevenfold from birth to puberty and further threefold during adolescence.
- Bone mass is stable until about age 50.
- During peri-menopause and menopause (a 5-10 year period) women lose more bone than men.
- At menopause, less calcium may be absorbed and more may be lost via urine. An increase in calcium intake will slow down bone loss and prevent fractures.
Are calcium supplements safe?
- Calcium supplements are not required if you eat the appropriate mineral-rich foods.
- Too much supplementary calcium can cause gut upsets such as constipation and bloat.
- Supplements providing 2000mg or more may increase your risk of heart disease.
- Discuss supplementation with your healthcare provider.
Discuss your personal requirements with your healthcare provider.
Calcium is available from a wide range of foods. In Australia, dairy foods provide most of the calcium.
If you don’t think that you are eating enough calcium-rich foods, then please discuss your personal requirements with your healthcare provider.