Blood pressure response to sodium restriction and potassium supplementation in healthy normotensive children.

To examine the effects of dietary sodium on blood pressure 149 healthy, normotensive children (64 males, 85 females) participated in a study to restrict sodium intake to 60 mEq/day or half of the usual intake for 3 months. Sodium excretion was significantly decreased during the study period (100.6 +/- 3.4 mEq vs 46.5 +/- 2.0 mEq, P less than .001). As a group there was no significant change in systolic and a small decrease in diastolic blood pressure (54.2 +/- 0.8 mmHg vs 53.0 +/- 0.7 mmHg, p less than .03, one tailed). Adjustment of blood pressure for weight and age and analysis of residuals yielded significant decreases in both mean arterial (p less than .05) and diastolic blood pressure (p less than .05). In the potassium supplement study, comparison of supplementation to post-supplement periods in 31 children (13 male, 18 female) showed a significantly lower (p less than .05) systolic blood pressure during supplementation (101.3 +/- 2.1 mmHg vs 103.3 +/- 20 mmHg). Analyses of diastolic pressures, sodium excretion and weight were not significant. These studies show heterogeneity in the blood pressure response to sodium restriction and suggest that sodium restriction and potassium supplementation have different effects on blood pressure in children.