Comparative studies of reduced sodium and high potassium diet in hypertension.

A decrease in sodium intake or an increase in potassium intake reduces blood pressure (BP) in people with essential hypertension. Additional potassium prevents, in sodium-sensitive people and rats, the rise in BP caused by extra sodium chloride. In people with a diastolic BP between 90 and 100 mm Hg, dietary reduction of sodium to 80 mmol/day and dietary increase of potassium to 90 mmol/day caused a fall in BP of 5.1/4.2 and 3.6/3.1 mm Hg, respectively, greater than was observed in the control group. There was a negative interaction between the two diets when used together with a BP change of 4.0/3.6 mm Hg. The fall in BP with sodium restriction was not reversed by the addition of sodium chloride and a similar fall in BP was not achieved with potassium chloride. It is possible that the response is due to some other factor. A strong correlation existed between the change in urine Na:K and the fall in BP. This study indicates that a reduced sodium or an increased potassium diet will reduce BP and should be considered for the initial management of essential hypertension.