Association of urinary sodium and potassium excretion with systolic blood pressure in the Dietary Approaches to Stop Hypertension Sodium Trial

Parul Chaudhary,Richard D Wainford

doi:10.1038/s41371-020-0375-8

Abstract

The 2019 National Academy of Science, Engineering and Medicine Dietary Reference Intakes (DRI) for Sodium (Na+) and Potassium (K+) Report concluded there remains insufficient evidence to establish a K+ DRI. This study tested the hypothesis that reduced Na+ and increased K+ excretion will positively associate with lower blood pressure in salt sensitive (SS) and salt resistant (SR) participants in the Dietary Approaches to Stop Hypertension Sodium Trial (DASH–Sodium). Via the NHLBI BioLINCC we accessed the DASH-Sodium dataset for data on systolic blood pressure (SBP), 24-h urinary Na+ and K+ excretion at screening (regular patient diet; N = 186, SS N = 222 SR) and post DASH diet (N = 71 SS, N = 119 SR). The relationships between SBP, urinary Na+ and K+ excretion, and Na+/K+ ratio were assessed via linear regression. At screening elevated urinary Na+ excretion positively associated with SBP in SS (1 g increase in urinary Na+ excretion = +1 0 ± 0.4 mmHg) but not SR participants, and urinary K+ excretion of <1 g K+/day was associated with higher SBP in SS and SR participants. Urinary K+ excretion ≥1 g/day, or a decreases in urinary Na+/K+ ratio, was not associated with lower SBP. Post the DASH–sodium diet intervention, SBP was reduced in SS and SR participants. However, no correlation was observed between reduced SBP and urinary K+ excretion or the urinary Na+/K+ ratio irrespective of the salt sensitivity of blood pressure. Our data support the DRI recommendation not to establish a K+ DRI and suggest further evidence is required to support a reduced Na+/K+ ratio to lower SBP.

Highlights

Hypertension, the most common non-communicable disease worldwide, represents a significant global public health issue
Of American adults consume an excess of dietary sodium (Na+), with an average daily consumption exceeding 3400 mg in adult US males, a value almost three times the daily consumption recommended by the American Heart Association (AHA) [4] and the National Academy of Science, Engineering, and Medicine
In contrast there was no significant difference in 24 h urinary Na+ excretion, 24 h urinary K+ excretion and the urinary Na+:K+ ratio between SS and salt resistant (SR) participants at screening (Table 2)

Summary

Introduction

Hypertension, the most common non-communicable disease worldwide, represents a significant global public health issue. Of American adults consume an excess of dietary sodium (Na+), with an average daily consumption exceeding 3400 mg in adult US males, a value almost three times the daily consumption recommended by the AHA [4] and the National Academy of Science, Engineering, and Medicine. Given that excess dietary Na+ intake, which can drive the salt sensitivity of blood pressure and increase hypertension risk, global dietary Na+ intake is a public health risk. Meta-analyses have correlated dietary Na+ restriction with reductions in blood pressure suggesting there is a health benefit in both normotensive and hypertensive individuals irrespective of the salt sensitivity of blood pressure [9, 10]

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