Fourteen reports have identified an association between lower dietary calcium consumption and higher blood pressure in adults. The relationship between dietary calcium and blood pressure status of humans may be modified by a wide variety of demographic, environmental, life-style, and nutritional factors. Reduced dietary calcium intake may be a proximate cause of several of the reported biochemical abnormalities of Ca2+ metabolism including the reductions in serum ionized Ca2+ concentrations and increases in circulating parathyroid hormone levels. The paradoxical increases in intracellular free Ca2+ observed in hypertension on low dietary Ca2+ intake suggest that a primary defect in the cellular handling of Ca2+ may exist, possible mediated through defective Ca2+ adenosine triphosphatase pump activity.