Calcium is by no means in any form good for health. Erin D. Michos, Johns Hopkins University, Baltimore, MD, USA, and colleagues found that a calcium-rich diet has positive effects on bones, vessels, and heart. This, on the other hand, is the reverse when a lot of calcium is consumed in the form of food supplements. Then the risk for arteriosclerosis even increases significantly.

For their study, the researchers evaluated the health data of 2,742 men and women aged 45 and older for ten years. They also studied the amount of calcium that the participants received via their diet and dietary supplements. A diet rich in calcium had a positive effect not only on the bones, but also on heart and vascular health. Those who received more than 1,400 mg of calcium daily developed 27 % less frequently an atherosclerosis or heart disease within the ten years. Those who had taken a similar amount of calcium as a tablet, developed 22 % more frequently atherosclerosis.

This may be due to the fact that dietary supplements contain calcium salts or because the calcium is taken at once in a large dose which the body cannot process. In fact, previous studies have already shown that calcium from dietary supplements often does not reach the bones. At the same time, however, this calcium is not excreted completely with the urine. This suggests that it accumulates in the tissues of the body. This could therefore promote deposits in the arteries.

• Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10‐Year Follow‐up of the Multi‐Ethnic Study of Atherosclerosis (MESA),
  John J.B. Anderson, Bridget Kruszka, Joseph A.C. Delaney, Ka He, Gregory L. Burke, Alvaro Alonso, Diane E. Bild, Matthew Budoff, Erin D. Michos,
  J. Am. Heart Assoc. 2016.
  DOI: dx.doi.org/10.1161/JAHA.116.003815