Calcium supplements controversy in osteoporosis: a physiological mechanism supporting cardiovascular adverse effects.

Recently, administration of calcium supplements for the prevention and treatment of osteoporosis has become a highly controversial issue. The findings of epidemiological studies are not necessarily supportive of the practice and are also open to different interpretations. In this article, we attempt to broaden the discussion and provide evidence that calcium supplementation may fail to compensate for renal calcium loss, and also that the resultant increased calcium load in the circulation could lead to extraskeletal deposition, including in the coronary arteries.