Calcium is a mineral important for strong bones and teeth. Too little calcium can lead to the bone conditions rickets and osteoporosis.
Calcium also has a role in blood clotting and the regulation of muscle contractions including the heartbeat.
There is some evidence calcium has a role in managing blood pressure and preventing breast and colon cancer.
Most people should get enough calcium from a balanced healthy diet, but calcium supplements may be recommended for some people.
Use of calcium
Calcium is commonly found in antacids used to treat indigestion. Doctors also use calcium to control high levels of magnesium, phosphorus and potassium in the blood. It’s possible but not proven that calcium may play a role in preventing certain cancers. It’s also possible but not proven that calcium with vitamin D may help protect against breast cancer in pre- menopausal women, but the data are still inconclusive for post- menopausal women, and the exact relationship regarding vitamin D and calcium intake is still not known. In fact, more recent analysis of an old trial involving more than 30,000 women has found that some participants taking combined vitamin D and calcium supplements were at an increased risk of suffering a heart attack or stroke. The British Heart Foundation says the study showed there was a modest increase in heart attack or stroke risk but that’s not the same as saying calcium supplements with vitamin D cause heart attacks and strokes, only that there was an increased risk. The research was published in the British Medical Journal and analysed data from 16,718 women who were not taking calcium supplements at the start of the Women’s Health Initiative study - a seven year trial involving 36,000 women.
While calcium has been looked at for other uses - such as helping with weight loss - these studies have been inconclusive.
People at risk of calcium deficiency include post- menopausal women, those who follow restrictive diets, and since dairy products are one of the most common sources of calcium, people who are lactose intolerant or who follow a vegan diet.
Calcium dose and instructions for use
The Department of Health has set a reference nutrient intake (RNI) for calcium. Getting this amount from your diet, with or without supplements, may be enough to keep your bones healthy. Your doctor may recommend higher doses, depending on your needs.
Calcium:Reference Nutrient Intake (RNI)
|0-12 months||525 mg/day|
|1-3 years||350 mg/day|
|4-6 years||450 mg/day|
|7-10 years||550 mg/day|
|11-18 years (females)||800 mg/day|
|11-18 years (males)||1,000 mg/day|
Women who are pregnant do not require more calcium, but those who are breastfeeding are recommended to have 1,250mg/day.
Taking too much calcium in high doses over 1500mg a day may cause stomach pain and diarrhoea.