Assessing sodium and potassium intake in essential hypertension

Abstract

A growing body of evidence links habitual sodium intake to the incidence and prevalence of essential hypertension. 1+2 Interest has increased in measuring habitual levels of sodium chloride intake and changes in populations and individuals. Moreover, sodium restriction as prevention or therapy of essential hypertension’-* requires accurate yet convenient methods to assess patient compliance with dietary instructions. Evidence exists that potassium intake and the ratio of sodium to potassium intake may also be important in determining blood pressure and the occurrence of essential hypertension.ss lo This makes estimation of potassium intake of interest. However, information on sodium and potassium intake from population studies is scanty.” Most nutritional investigators who use dietary recall techniques have felt these measures would not yield reliable estimates of sodium and potassium intake. Collecting 24-hour urine samples to measure sodium and potassium excretion is often logistically infeasible in both population samples and patients. Hence, few studies have cross sectionally compared intake estimated by dietary recall or food diary with urinary excretion, and no studies have compared methods for assessing change in intake. Therefore, we undertook an evaluation of these methods, comparing them to 24-hour urine collections in free-living adult men. The results are contained in the present article, which also reviews the validity of various methods for assessing sodium intake.