[Effect of dietary sodium in hypertension not treated with drugs]

The usefulness of salt restriction in essential hypertension is still now disputed. This study was designed to test the influence of a diet with and without salt restriction in 19 untreated essential hypertensives (12 with and 7 without family history of hypertension) and free of cardiovascular and renal complications. Each patient was examined after a placebo period, after 1 month of salt restriction, and after 1 month of salt supplementation. Weight, blood pressure, 24 hours urinary sodium excretion and red blood cell ionic fluxes were measured. In patients with hypertensive heredity, the blood pressure did not change. The intracellular sodium concentration, the cotransport and the countertransport remained stable. The ouabain sensitive sodium pump slightly increased during salt restriction and remained stable after salt supplementation. In patients without such hypertensive heredity (who were older and heavier), sodium restriction period was characterized by significant decrease in blood pressure, weight, intracellular sodium concentration and increase in sodium pump activity. When salt was increased, all the parameters remained stable. A more balanced diet with sodium restriction decreases the blood pressure in relation to age, weight and the blood pressure level. Hypertensive heredity does not seem to be a parameter of salt sensitivity. The blood pressure decrease is also related to the quantitative importance of sodium restriction. The ouabain sensitive pump activity changes during diet especially in relation to weight loss and decreasing salt intake.