Calcium is a mineral. About three-quarters of the calcium we eat comes from dairy products and grains. Some foods have calcium added to them, such as cereals or soy milk. This is helpful for people who may not be able to eat dairy food.
About 99% of the body’s calcium is stored and used in our bones and teeth, but it helps out elsewhere too. We need to get enough in our food to keep us healthy. Too little calcium (a deficiency) can lead to poor growth, weak bones and bad teeth. People who are growing bones (like teenagers or pregnant women) need more calcium. The NZ Ministry of Health estimates that about one-third of our 12 to 18 year olds may not be getting enough.
Calcium is a mineral. We get most of our calcium from the fluids of plants and animals. It is also found naturally in our environment, such as in rocks like limestone.
About three-quarters of the calcium we eat comes from dairy products and grains, and most of the rest from vegetables, protein-rich foods, sugars, and fruits. Leafy vegetables, dairy, canned fish, legumes, dried fruits, nuts and seeds are great sources. If someone can’t eat dairy foods they can also get calcium from fortified cereals or plant milks (e.g. soy, almond). If a food is fortified with calcium it means that calcium has been added to it.
Yes. Vitamin D helps with absorbing (absorb means to soak up or take in) calcium from food in the gut, and getting it into our bones so it’s very important to make sure we also get enough of it. Some foods including spinach and rhubarb – and some legumes, grains and seeds – contain substances (oxalates and phytates) which make it harder to absorb their calcium, but they don’t generally get in the way with absorbing calcium from other foods eaten at the same time.
Calcium is necessary for healthy bones and teeth. We also need it for nerve signalling (messages sent from the brain) and muscular contractions (when we tighten our muscles). And it’s involved in balancing the strength of acid in our blood, the release of certain hormones and enzymes, and blood clotting. We need a daily supply because we’re constantly recycling and replacing the calcium in our bones and losing it in our sweat and urine (pee). People who are growing bones (like teenagers or pregnant women) or less able to absorb calcium (like older people) need more calcium. The NZ Ministry of Health estimates that about one-third of our 12 to 18 year olds may not be getting enough calcium.
Too little calcium (a deficiency) can lead to poor growth, weak bones and bad teeth. In older people a deficiency may lead to the condition called osteoporosis (a bone disease). A lesser deficiency may show up as tingling, twitches, numbness or muscle cramps. We’re unlikely to get too much calcium naturally, but overdoing the calcium supplements for a long time might lead to constipation, kidney stones or an increased risk of heart attack from stiffened arteries.
Calcium is the most plentiful metal in the human body). About 1.5% of our bodyweight is calcium: there’s 750 g of it (the weight of a large block of cheese) in a 12-yr-old who weighs 50 kg!
|
Food – and serve size |
Calcium (mg/100 g or 100 mL) |
Calcium (mg/ per serve) |
|
Sesame seeds – 1 tablespoon |
980 |
84 |
|
NZ cheddar cheese – 2 cm cube |
850 |
68 |
|
Low fat cottage cheese – 250 g pottle |
86 |
215 |
|
Fortified Special K cereal – 1 cup |
780 |
320 |
|
Canned sardines – 5 sardines |
550 |
330 |
|
Canned salmon – 210 g serve |
270 |
567 |
|
Dried figs – 1 fig |
200 |
32 |
|
Raw kale – 1 cup |
280 |
120 |
|
Mesclun salad leaves – 1 cup |
150 |
56 |
|
Raw spinach – 1 cup leaves |
69 |
30 |
|
Canned kidney beans – 1 cup, drained |
50 |
110 |
|
Fortified fruit yoghurt (standard or lite) – 125 g pottle |
190 |
238 |
|
Milk, yellow top Calci+ trim (0.2% fat) – 250 mL cup |
190 |
475 |
|
Milk, standard blue top (3.3% fat) – 250 mL cup |
120 |
310 |
|
Fortified soy milk – 250 mL cup |
110 |
290 |
|
White or wheatmeal sandwich bread – 2 slices |
85-86 |
52-54 |
|
A milligram is one thousandth of a gram (g). |
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The NZ Nutrition Foundation recommends a daily dietary intake (RDI) of calcium of 1000 mg for 9- to 11-year-olds, and 1300 mg for 12- to 18-year-olds. Adults also need 1000 mg –increasing to 1300 mg for men over 70, and women who are over 50 or pregnant. Manufacturers use a RDI value of 800 mg when calculating the % RDI values on packaging.
Kid’s Health, September 2014. “Calcium”. Retrieved from: http://kidshealth.org/en/teens/calcium.html# 17 August 2017.
Ministry of Health, July 2012. “Food and Nutrition Guidelines for Healthy Children and Young People (Aged 2–18 years): a Background Paper. Partial Revision February 2015.” Retrieved from: http://www.health.govt.nz/system/files/documents/publications/food-nutrition-guidelines-healthy-children-young-people-background-paper-feb15-v2.pdf 17 August 2017.
National Institutes of Health, 17 November 2017. “Calcium Factsheet”. Retrieved from: https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/ 17 August 2017.
New Zealand Nutrition Foundation, April2013. “Calcium”. Retrieved from: https://www.nutritionfoundation.org.nz/nutrition-facts/minerals/calcium 17 August 2017.