Low-sodium salt substitute reduces SBP in hypertensive patients

Use of a salt substitute with less sodium and more potassium results in a substantial decrease in systolic blood pressure (SBP) in hypertensive patients, reports a study.

“[W]e demonstrated that replacement of regular salt with a reduced-sodium added-potassium salt for home use for 3 months led to substantial reductions in SBP in hypertensive patients in rural India,” the researchers said. “These findings support the use of such salt substitutes … as a low-cost and practical intervention to reduce BP in this setting.”

Five hundred two hypertensive individuals (mean age 61.6±12.0 years, 58.8 percent women) from seven villages in rural India were randomized to receive either regular salt (100-percent sodium chloride) or the salt substitute (70-percent sodium chloride, 30-percent potassium chloride blend) and advised to replace all home salt use.

Of the participants, 494 (98 percent) completed 1 month and 476 (95 percent) completed 3 months of follow-up. The salt substitute intervention significantly reduced the average SBP by 4.6 mm Hg (95 percent confidence interval [CI], 3.0–6.2; p<0.001) and diastolic BP by 1.1 mm Hg (95 percent CI, 0.2–2.1; p=0.02) at 3 months. [Am J Clin Nutr 2021;114:185-193]

Compared with the control group, the salt substitute group had a significant increase in 24-hour urinary potassium excretion by 0.24 g/day (95 percent CI, 0.12–0.35; p<0.001) and a decrease in urinary sodium-to-potassium ratio by 0.71 (95 percent CI, 0.55–0.87; p<0.0001). Moreover, participants reported using the study salt almost daily (mean 6.3±1.8 days) and rated its taste similarly.

“Participants rated the taste of the study salt substitute favourably and our findings suggest that they readily incorporated the salt substitute into their daily cooking habits,” the researchers said. “Overall, our data suggest that the replacement of salt with a reduced-sodium added-potassium salt substitute is an acceptable and effective dietary intervention for lowering SBP in hypertensive individuals.”

Barriers to medical care and access to medication, especially in rural areas, exist despite the high prevalence of hypertension in India, which then leads to poor control of the disease. [J Hypertens 2014;32:1170-1177; Curr Opin Cardiol 2019;34:331-341]

“In this context, using a salt substitute is a promising complement to therapeutic interventions,” the researchers said. “The magnitude of effect on BP is clinically meaningful with a 5-mm Hg reduction in SBP anticipated to reduce the overall risk of cardiovascular disease by ≥10 percent.” [Lancet North Am Ed 2016;387:957-967]

Of note, none of the participants were aware that there are reduced-sodium salts existing in the market. Data from the current study suggest that public promotion and greater availability of salt substitutes for hypertensive patients could be an effective and scalable intervention.

Salt substitutes are cheap but are about one-third more than the cost of regular salt. This could potentially deter its widespread use, particularly for lower-income populations. A price subsidization policy might be warranted.

“Furthermore, additional studies and government investments are needed to ascertain possible supply chain issues related to potassium salt substitutes, such as how to scale-up their production and implement efficient distribution networks to enhance availability,” the researchers said.