Salt substitutes may lower stroke recurrence and death risk

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Danielle Ellis, B.Sc.Feb 7 2025

Large clinical trial shows that replacing regular salt with a sodium-potassium blend offers a simple, low-cost intervention for stroke patients

A recent randomized clinical trial claims that salt substitutes are safe and effective over regular salt in terms of reducing the risk of recurrent stroke and death in patients with a history of stroke. The detailed trial report is published in JAMA Cardiology.

Background

Stroke is a leading cause of death and long-term disability, particularly in low- and middle-income countries. An estimated recurrence rate of stroke is 10% at one year and 15% at five years in patients with a history of stroke.

In China, the recurrence rate of stroke is significantly higher than the global estimates, with 17% at one year and 41% at five years. This could be due to the higher prevalence of hypertension (high blood pressure) in China.

Controlling hypertension is considered a key strategy to reduce stroke risk. Several clinical trials have reported that reducing sodium and supplementing potassium in the diet is associated with effective control of hypertension.

Salt substitutes, which replace a portion of sodium with potassium, have been found to have long-term blood pressure-lowering effects across diverse populations.

The Salt Substitute and Stroke Study, an open-label, randomized clinical trial, was conducted in 600 northern Chinese villages. The trial, which involved 20,995 participants, previously reported that salt substitutes can significantly reduce the risks of stroke, total cardiovascular events, and premature death.

In the current study, researchers conducted a secondary analysis of the Salt Substitute and Stroke Study data to determine the effect of salt substitutes on recurrent stroke and mortality in patients with a history of stroke.

The study

This study included a subgroup of patients from the Salt Substitute and Stroke Study who self-reported a hospital diagnosis of stroke at baseline. This led to the inclusion of 15,249 patients who were randomly assigned to the intervention group and the control group.

The intervention group participants received a salt substitute consisting of 75% sodium chloride and 25% potassium chloride. In the control group, participants received regular salt. The study's median follow-up duration was 61 months.

Important observations

The study reported that salt substitute consumption leads to a modest reduction in systolic blood pressure (−2.05 mm Hg) over the follow-up period of 61 months. During this period, 2735 recurrent stroke events and 3242 deaths occurred among participants.

The recurrence rates of stroke in the intervention and the control group were 16% and 19%, respectively. This accounted for a 14% reduction in the recurrence rate among participants who consumed the salt substitute.

The positive effect of salt substitute on the recurrence rate was stronger for hemorrhagic stroke compared to that for ischemic stroke.

In addition to the stroke recurrence rate, the intake of salt substitutes was associated with a 12% reduction in all-cause mortality and a 21% reduction in stroke-related mortality. The effect of salt substitutes on all-cause mortality was most pronounced for deaths related to vascular causes.

Notably, no significant difference in hyperkalemia events (high blood potassium level) was observed between the intervention and control groups, indicating that salt substitutes are safe and do not increase the risk of cardiac events caused by high blood potassium levels.    

Study significance

The study reveals that salt substitutes can be used safely in the diet of stroke patients to reduce the risk of recurrent stroke and mortality.

These risk reduction effects of salt substitutes are independent of the participant’s age, sex, educational status, body mass index, blood pressure, diabetes, and anti-hypertensive medication use.

Researchers believe that salt substitutes' health benefits can be attributed to their blood pressure-lowering effect. In this context, existing evidence indicates that dietary sodium reduction and potassium supplementation work synergistically to reduce blood pressure.

Participants who consumed salt substitutes had a modest reduction in systolic blood pressure (−2.05 mm Hg) over 61 months. Previously, it has been shown that even a 1 mm Hg reduction in systolic blood pressure can lead to a 5% reduction in stroke risk.

These observations collectively suggest that salt substitutes as a low-cost intervention can be used in the diet of high-risk people for stroke management.

Researchers mention that such interventions would be particularly suitable and effective in rural China. Adults in these regions consume high amounts of sodium through the home-cooking process and low amounts of potassium due to inadequate fruit and vegetable consumption.

Researchers mention some limitations of the study. The intervention assessed in the study was not blinded as the Salt Substitute and Stroke Study was open-level. Moreover, the study findings should be considered exploratory as they are a secondary subgroup analysis of the Salt Substitute and Stroke Study data.

Despite these limitations, the study provides a safe and cost-effective dietary intervention for stroke survivors that can significantly improve secondary prevention of stroke and cardiovascular health on a global scale.