Description Calcium is an essential mineral.
Function/ Used for The most abundant mineral in the body, calcium is essential for building and maintaining healthy bones and teeth.

Calcium also plays a role in muscle contraction, including the heart muscle; facilitates nerve transmissions; is involved in energy production and cell division and is used in the blood clotting mechanism.

Intake Recommended intake

EU NRV: 800mg


UK average daily intake

Requirements vary depending on age and gender. The UK National Diet and Nutrition Survey lists up-to-date intake requirements and average intakes1.

As a supplement Available as a single supplement. Also commonly available as part of a multivitamin and mineral formula.

Different multivitamin and minerals products will vary in the percentage NRVs they include. People should always check the label for information about a specific product.

Found in (dietary sources) Good sources include dairy products, canned fish such as sardines (when the soft, edible bones are consumed), dark green leafy vegetables, white bread, brown bread, sesame seeds and pulses.
Deficiency Long term deficiency leads to osteoporosis, muscle aches and pains, muscle twitching and spasm, muscle cramps; rickets (in children), osteomalacia (softening of bones), heart disorders, brittle nails and insomnia.
Precautions and contraindications Calcium supplements should be avoided in conditions associated with hypercalcaemia (high calcium levels in the bloods) and hypercalcuria (elevated calcium in the urine), and in renal (kidney) impairment (chronic).2

Safe Upper Level: 1500mg/day3

Use in pregnancy and breastfeeding No problems have been reported. Calcium supplements may be required during pregnancy and breast-feeding and should be combined with vitamin D to ensure effective absorption.4
Interactions e.g. with other medications Excessive alcohol intake may reduce calcium absorption.

Aluminium- and magnesium-containing antacids may reduce calcium absorption.

Calcium can decrease absorption of some antibiotics, biphosphonates (to treat osteoporosis) and anti-convulsants (to treat epilepsy).

Loop diuretics increase excretion of calcium in the urine whereas thiazide-type diuretics may reduce calcium excretion.

Calcium carbonate or calcium phosphate may reduce absorption of iron and should be given 2 hours apart.5

Adverse effects Reported adverse effects with calcium supplements include nausea, constipation and flatulence (usually mild).
References 1.

2.     Mason, P. Dietary Supplements. Pharmaceutical Press, London, 2001.

3.     Expert Group on Vitamins and Minerals, 2003.

4.     NHS Choices Vitamins, supplements and nutrition in pregnancy

5.     Gaby, A. R. A-Z Guide to Drug-Herb-Vitamin Interactions. HealthNotes 2006.