Effect of Low vs. High Dietary Sodium on Blood Pressure Levels in a Normotensive Indo-Asian Population

Background: Hypertension is a major modifiable risk factor, and while sodium restriction in hypertensive Patients appears effective, its role in normotensive individuals remains unclear. We assessed the effect of a low vs. high-sodium diet on blood pressure in normotensive Indo-Asian adults. Methods: A randomized, controlled, crossover trial was conducted on 200 normotensive subjects randomly selected from the general population in Karachi, Pakistan. Participants were randomized to either a low (20 mEq/day) or a high-sodium diet (220 mEq/day) for 1 week, followed by 1 week of washout, then the alternate diet for I week. The primary outcome was difference in systolic blood pressure (SBP) measured at the end of each phase in the overall population. Results: Mean (95% confidence interval) decline in 24-h urinary sodium excretion was 81.0 (69.6-92.4) mEq/day (P \u3c 0.001), and in SBP was 1 (0-3) mm Hg (P= 0.17) between high and low-sodium phase. A significant interaction was detected (P=0.001) between dietary sodium and baseline SBP with a greater adjusted mean (95% confidence interval) decline in SBP (6 (2-9) mm Hg) among participants with high-normal SBP (130-139 mm Hg) and no significant change (-1 (-2 to 1)) in those with normal baseline SBP