Intake of low sodium salt substitute for 3years attenuates the increase in blood pressure in a rural population of North China - A randomized controlled trial

Abstract

Background: Lowering salt intake is one of the successful and cost-effective methods to reduce blood pressure (BP). In this randomized controlled study, we investigated the effects of a 3-year substitution of table salt with a low-sodium salt substitute in a rural population of North China.

Methods: Subjects from 200 families residing in five villages in Liaoning, North China were registered in this study and randomly divided into two groups: normal salt (100% sodium chloride) and low salt substitute (65% NaCl, 25% KCl, 10% MgSO4). We compared the effects of the low-sodium salt substitute and normal salt on differences in BP from baseline to various follow-up time points during this 3-year study period. We also examined several factors that may affect the long-term changes in BP. Hypertension was defined per World Health Organization guidelines as BP≥140/90mmHg.

Results: The low sodium substitute significantly reduced the increase in both systolic and diastolic BP compared with the regular salt (P=0.000). Also, the population aged 40-70years showed most beneficial response to the salt substitute compared with those aged <40 or >70years. The low salt substitute had similar beneficial effects in both males and females. In addition, the salt type consumed and body mass index significantly affected the change in BP.

Conclusion: Use of the salt substitute significantly reduces the increase in BP over a long term, and thus, the salt substitute can be used as a replacement for regular salt in the daily diet to prevent/diminish the incidence of hypertension.

Keywords: Blood pressure; Hypertension; Salt substitute; Table salt.