Introduction

Abstract

Calcium is one of 21 elements known to be essential to humans. It is one of three minerals required in the diet in relatively large quantities and for which a Dietary Reference Intake (DRI) has been established by the Food and Nutrition Board. At this writing, calcium requirements are set as Adequate Intakes (AI) rather than as Recommended Dietary Allowances (RDA). The decision to set an AI rather than an RDA by the 1997 Food and Nutrition Board related more to the use of a new approach for determining optimal calcium intakes than to the stated paucity of data for determining calcium requirements. Calcium is the most studied of the minerals in relationship to human health. In Spring 2004, a Medline search for articles about minerals published between 1994 and 2004 yielded 62,852 articles about calcium. The next most cited minerals were iron (14,963 articles), zinc (10,399 articles), and magnesium (10,097 articles). The most cited common mineral deficiencies in the world are in iron, iodine, and zinc. Yet, more people are further from their recommended intakes for calcium than for any of these minerals. Inadequate calcium intake has such a long latency period before signs of disease are apparent that its association with health is not adequately appreciated. This book covers the functions of calcium, the approaches for determining calcium intakes for optimal health, and the relationship of calcium status to long-studied and newly identified diseases.