The calcium deficiency hypothesis of hypertension.

The proposed role of maintenance of calcium homeostasis in the prevention and nonpharmacologic treatment of hypertension has prompted controversial interpretations of the data on which the proposal is based. To provide a more current perspective, we summarize the epidemiologic data, results of clinical studies of calcium metabolism in humans with hypertension, effects of controlled interventions of calcium supplementation in humans, and findings from laboratory studies intended to elucidate possible mechanisms. Data from the epidemiologic and clinical trials support a protective role for calcium in regulating arterial pressure. A potentially important relationship between the "calcium hypothesis" and "salt-sensitivity" may provide further insights into the mechanisms involved. Results of experiments in vascular physiology indicate that dietary calcium's effect in lowering blood pressure is mediated in part through direct action on the vasculature.