THE EFFECT OF LOW SODIUM INTAKE ON THE ALDOSTERONE-TO-RENIN RATIO IN ESSENTIAL HYPERTENSIVES

Objective: The purpose of this study is to identify the effect of a low sodium intake on the aldosterone-to-renin ratio (ARR).Design and method: To this end, we put 88 non-medicated essential hypertensive patients who were previously on an ad libitum diet to a low sodium diet (55 mmol/day) for one week. Changes in renin, aldosterone, and the aldosterone-to-renin ratio were assessed on the first three days (early response) and the seventh day (late response) after sodium restriction. Results: Overall, active plasma renin concentration rose from a median of 16.5 mU/L on day 1 to 17.0, 21.0 and 23.9 mU/L on days 2,3, and 7 respectively. The corresponding aldosterone levels were: 305, 373, 380 and 370 pM/L. The ARR, on the other hand, did not change significantly during this period. Nevertheless, marked heterogeneity was found among the individuals. Based on the early renin response to salt reduction, the group was divided into tertiles with an atypical response (decline in renin), a blunted response, and a normal response, respectively. Despite these differences, the ARR did not exhibit any significant change after seven days of sodium restriction Conclusions: To conclude, acute changes in dietary sodium intake result in a significant rise of both aldosterone and renin but not the aldosterone-to-renin ratio. The long-term effect of low sodium diet warrants further investigation.