Calcium is a chemical element which is essential for living organisms, including humans.
Calcium's chemical symbol is "Ca". It is found in many foods. We need to consume a certain amount of calcium to build and maintain strong bones and healthy communication between the brain and various parts of the body.
The National Health Service (NHS)1, UK, says there is more calcium in the human body than any other mineral.
Calcium continues strengthening the bones of humans until they reach the age of 20-25 years, or when they reach their peak mass. After that age, the element helps bone maintenance as well as slowing down bone density loss, which is a natural part of the aging process. People whose calcium intake is inadequate before the age of 20-25, have a considerably higher risk later on in life of developing brittle bone disease or osteoporosis, because calcium is drawn from the bones as a reserve.
Calcium regulates muscle contraction, including the heartbeat. It also plays a key role in normal blood coagulation (clotting).
Nearly all of the calcium in our bodies is stored in our teeth and bones, where it supports their hardness and structure.
Calcium also plays a role in the release of hormones and enzymes, as well as helping blood vessels move blood around the body. A 2010 study carried out in North Carolina State University found that adequate calcium early in life may protect against obesity later on2.
Vitamin D helps our bodies absorb and retain calcium in the bones.
According to the NIH (National Institutes of Health)3, approximately 43% of all American adults take dietary supplements - 70% of adult females do. Users increase their calcium daily intake by about an average of 300 mg per day through supplements. Adult females are more likely to consume inadequate amounts of calcium compared to adult males.
Calcium rich diets increase women's lifespans4 - women whose diets are rich in calcium probably live longer than their counterparts whose diets are low in calcium, researchers from McGill University in Canada reported in the Journal of Clinical Endocrinology and Metabolism.
Calcium rich foods
According to health authorities in North America and Western Europe, dietary calcium can be found in several different foods and drinks; they also recommend that we obtain our calcium from a variety of sources.
The following foods and drinks are rich sources of calcium:
Milk, cheese and yoghurts are common sources of calcium.
- Seaweeds, such as kelp, hijiki and wakame
- Nuts and seeds, including pistachio, sesame, almonds, hazelnuts
- Dandelion leaves
- Many fortified breakfast cereals
- Many fortified drinks, including soy milk and a variety of fruit juices
- Crushed eggshells - they can be ground into a powder and added to foods and/or drinks
Some dark-green vegetables may contain high levels of oxalic acid which reduces the body's ability to absorb calcium.
How much calcium should I consume each day?
According to the Institute of Medicine (IoM), we should consume calcium daily at the following amounts:
- age 0 to 6 months: 200 mg per day
- age 7 to 12 months: 260 mg per day
- age 1 to 3 years: 700 mg per day
- age 4 to 8 years: 1000 mg per day
- age 9 to 18 years: 1300 mg per day
- age 19 to 50 years: 1000 mg per day
- breastfeeding or pregnant teenager: 1000 mg per day
- breastfeeding or pregnant adult: 1000 mg per day
- age 51 to 70 years (male): 1000 mg per day
- age 51 to 70 years (female): 1200 mg per day
- age 71+ years: 1200 mg per day
On the next page we look at calcium deficiency, calcium supplements and possible side effects of calcium supplements.