Salt substitution: a low-cost strategy for blood pressure control among rural Chinese. A randomized, controlled trial

Objective Dietary sodium and potassium consumption is associated with blood pressure levels. The objective of this study was to define a practical and low- cost method for the control of blood pressure by modification of these dietary cations in rural Chinese. Methods This study was a double- blind, randomized, controlled trial designed to establish the long- term effects of a reduced- sodium, high- potassium salt substitute ( 65% sodium chloride, 25% potassium chloride, 10% magnesium sulphate) compared to normal salt ( 100% sodium chloride) on blood pressure among high- risk individuals. Following a 4- week run- in period on salt substitute, participants were randomly assigned to replace their household salt with either the study salt substitute or normal salt for a 12- month period. Results The mean age of the 608 randomized participants was 60 years and 56% of them were female. Sixty- four percent had a history of vascular disease and 61% were taking one or more blood pressure- lowering drugs at entry. Mean baseline blood pressure was 159/ 93mmHg ( SD 26/ 14). The mean overall difference in systolic blood pressure between randomized groups was 3.7mmHg ( 95% confidence interval 1.6 - 5.9, P< 0.001). There was strong evidence that the magnitude of this reduction increased over time ( PU0.001) with the maximum net reduction of 5.4mmHg ( 2.3 - 8.5) achieved at 12 months. There were no detectable effects on diastolic blood pressure. Conclusion Salt substitution produced a substantial and sustained systolic blood pressure reduction in this population, and should be actively promoted as a low- cost alternate or adjunct to drug therapy for people consuming significant quantities of salt.