Serum calcium and salt restriction in the diet of patients with essential arterial hypertension.

Serum concentration of ionic calcium and the effect of dietary salt restriction on serum total calcium was studied in patients with essential arterial hypertension. The concentration of serum ionic calcium was significantly lower than in controls in all the evolutive stages of the disease (p less than 0.005; p less than 0.005; p less than 0.001). During salt restriction serum total calcium rises significantly (p less than 0.005) as compared with the values found under a salt containing diet. It was suggested that increased chronic ingestion of sodium or restriction of dietary salt produces alterations in Na-Ca exchanges across semipermeable membrane of the smooth muscle.