DIETARY CALCIUM, CALCITROPHIC HORMONES, AND HYPERTENSION

A considerable number of trials have indicated that supplemental calcium intake has a consistent antihypertensive effect in some populations, though not others. It appears that salt sensitivity plays an important role in this respect, i.e. a blood pressure-lowering effect is especially likely in salt-sensitive individuals. Salt sensitivity may be a manifestation of calcium deficiency, which accordingly may contribute to the development and manifestation of high blood pressure. Against this background the conclusions of studies on the antihypertensive effects of calcium supplementation are reviewed, with attention being paid to the importance of baseline intake. It is suggested that the coupling of salt sensitivity with low calcium intake is of significance for hypertension in blacks and the elderly, Possible mechanisms through which calcium may prevent salt-induced increases in blood pressure are suggested. It is concluded that raising dietary calcium into the recommended range is an achievable and desirable goal, without untoward side-effects.