High Level of Calcium Intake and Supplements May Be Harmful
In a study of over 60,000 women, Swedish researcher Karl Michaëlsson et al. found that those women with the highest intakes of calcium (>1400mg/day) were at higher risk of mortality, particularly from cardiovascular causes such as cardiovascular disease and heart disease (but not stroke), than women with calcium intakes of between 600 and 1000mg/day. The research was published in the journal BMJ in 2013.
While calcium dietary supplements were not associated with elevated risk per se, those women with the highest calcium intake levels who also took supplements had a risk of mortality from all causes that was more than 2.5 times that of women with similar total calcium intake who did not take supplements.
Calcium levels in blood are tightly controlled by the body, but very low or very high calcium intake levels can override this control, causing imbalances.
The efficacy of calcium supplements for conditions such as osteoporosis or chronic kidney disease has not been established, and a healthy balanced diet and avoidance of water filters that remove calcium from drinking water may be best.
