Calcium revisited: part I.

In February 2013, the US Preventive Services Task Force (see www.uspreventiveservicestaskforce.org) recommended 'against daily supplementation with 400 IU or less of vitamin D3 and 1000, mg or less of calcium for the primary prevention of fractures in non institutionalized postmenopausal women', which illustrates the divergence of opinions. This review wants to shed an objective light on the importance of calcium for bone health. It cannot compete with an exhaustive analysis of the literature by an institute. It does not mention all significant references. But it highlights some pivotal studies from the past and it refers to recent studies that opened new views or added essential data to known facts. It also reflects the personal perception of the author. The first part deals mainly with intake, absorption, needs and recommendations; the second part will discuss the effects of calcium and its supplements on bone.