Concurrent Nutrient Changes with a Decrease in Dietary Sodium

Method: A 6-center randomized placebo controlled trial was instituted to assess the effect of dietary sodium on the effectiveness of isradipine in subjects with essential hypertension. After baseline evaluation, 99 hypertensive subjects were counselled to restrict dietary sodium to 60-80 mEq/day; all subjects received a comprehensive manual on a sodium-restricted diet and individual counselling by a dietitian. No advice regarding other nutrients was given. After a 4-week run-in period to assess compliance, subjects with urinary Na <120 mEq/24 hrs were continued on 8 weeks of sodium restriction. 24-hour recalls were obtained every 2 weeks and analyzed by the NCC database for nutrient intake. Results: Sodium intake was reduced by 50 mEq to 64±25 mEq. Intakes of most nutrients decreased significantly (p<0.01) with sodium restriction, including calcium, carbohydrate, protein, total and saturated fat, iron, potassium, phosphorus, zinc, riboflavin, and thiamin. Calories decreased from 1932±577 KCal at baseline to 1662±514 KCal with sodium restriction. The most notable changes were: 23% decrease in total fat (35% to 31% of KCal) _; 16% decrease in calcium intake (703±342 mg to 588±259 mg) ; 14% in iron (14±6 mg to 12±14 mg); and 6% in potassium (2645±918 to 2495±851 mg). Conclusion: The effect of dietary sodium restriction must be carefully weighed with a concomitant effect on other nutrients. While in reduction in total fat is beneficial, reduction in calcium, iron, and potassium intakes may offset this.