Low-sodium diet versus low-sodium/high-potassium diet for treatment of hypertension.

In 21 patients with essential hypertension the effects of moderate sodium restriction from the usual 200 mmol Na/day to 80 mmol/day over 4 weeks were compared with the effects of a combined low-sodium/high-potassium intake (80 mmol Na/120 mmol K) which was also given over 4 weeks in an open crossover trial. Systolic blood pressure in nine untreated patients with essential hypertension decreased significantly by between 5 and 7 mm Hg during moderate sodium restriction; no further decrease of blood pressure occurred during the combined low-sodium/high-potassium diet. In 12 treated patients with essential hypertension moderate sodium restriction or the combined low-sodium/high-potassium diet enabled a marked reduction of anti-hypertensive therapy in eight patients without impairment of blood pressure control (β-blockers by an average of 32%, saluretics by an average of 27% and vasodilators by an average of 24%). Here there were also no substantial differences between low-sodium intake and the combined low-sodium/high-potassium intake. It is concluded that sodium restriction to 80 mmol/day is effective in lowering systolic blood pressure but that a combined low-sodium/high-potassium diet does not further improve blood pressure control if the usual potassium intake is at least 80 mmol/day. Considerable reduction of anti-hypertensive therapy may be achieved by practical moderate sodium restriction.