Amounts of calcium in the human body exceed those of any other mineral. More than 99% of the calcium in the body is used to form and keep bones and teeth strong. The remaining amount is needed to maintain other essential functions throughout the human body.
Dairy foods like cheese, milk and yoghurt are the richest in calcium. Leafy, green vegetables, grains as well as other calcium fortified foods can add to the dietary intake of the mineral.
Health Effects of Calcium
Apart from forming bones and teeth the remaining 1% of calcium is used by the body to help blood vessel and muscle contraction and expansion, which in turn regulate heartbeat, ensure normal blood clotting and form various enzymes and hormones.
Calcium ion movement through the cytoplasm (cell fluid) also works as a signalling mechanism. Both intercellular signals related to inner processes of the cells as well as nerve transmissions around the body utilize calcium.
Calcium levels in the muscles, blood and fluid between cells are very carefully controlled by complex regulatory systems and do not vary much with dietary intake changes. Bone tissue is used as a storage space and also store of calcium depending on what is needed to maintain constant calcium concentration in the soft tissues of the body.
The amounts of calcium that are stored in the bones are used to support their function and structure. Bones normally continuously remodel changing with age – this process involves resorption and calcium deposition in the newly formed bone.
Resorption and deposition balance depends on age, as more calcium is deposited during growth, especially in children, whereas in elderly people resorption is more prominent and is accompanied by bone breakdown.
Excess Calcium and Deficiency
High doses of calcium usually cause stomach pain and diarrhea. Continued excessive intake results in elevated calcium levels in the blood (condition also known as hypercalcemia). This leads to accumulation of calcium in the soft tissues.
High calcium intake can also cause constipation and increase risk of developing kidney stones. However, it is very rare that calcium is consumed in excess only from dietary sources, even if calcium intake is too high due to taking too much of the supplements, it does not often result in the hypercalcemia condition, usually some of the less adverse symptoms appear first.
Calcium deficiency is normally caused by poor absorption, insufficient intake or excessive losses of calcium through excretion. Deficiency usually affects the bone structure first as calcium from there is used up to keep blood calcium levels normal, this can lead to bone softening, osteoporosis (generally weaker and more brittle bones) or even to deformations in bones and growth retardation in children – a condition called rickets.
If blood calcium levels are low as well, it can lead to tetany – excessive nerve activity. Some symptoms of the illness are muscle spasms and pain, tingling and numbness of extremities.
Recommendations for Calcium Intake
Nevertheless, following a balanced and varied diet should provide the body with all the calcium it needs and help avoid any of the above mentioned conditions.
The Tolerable Upper Intake Level to avoid excess intake of calcium is set at 2500 mg per day for adults and 1000-3000 mg for children depending on age.
However, the Recommended Daily Intake to completely satisfy your body’s requirement for calcium is:
- Adults – 1000 mg
- Children (9-18 years) – 1300 mg
- Children (1-8 years) – 700-1000 mg depending on age
- Infants – 200-260 mg depending on age
- Elderly people – 1200 mg