Research has demonstrated that excess sodium intake is a causal risk factor for hypertension, and reduction of dietary salt is advocated as an intervention for hypertension by most national and international hypertension societies.
Replacing regular salt with a salt substitute is a commonly recommended practical method for reducing sodium intake, salt substitutes replace a portion of the sodium chloride with other salts including potassium chloride and magnesium sulfate, but it was unclear if these substitutes can help to reduce blood pressure among those with hypertension.
The Salt Substitute in India Study examined the acceptability, usage, and blood pressure effects of a reduced-sodium and added potassium salt substitute among hypertensive patients. This controlled study was double-blind, randomized with an intervention duration of 3 months that involved 502 participants with hypertension from 7 villages in rural India who were randomly assigned to receive regular salt or the salt substitute and advised to replace all home salt use with that provided.
For this study, registered at clinicaltrials.gov as NCT03909659, the major outcome was the changes in systolic blood pressure from baseline to the end of the 3 month period when comparing the salt substitute and regular salt intake groups, while also assessing changes in diastolic blood pressure, 24-hour urinary markers, and self-reported use and satisfaction with the salts provided.
Of the 502 participants, a total of 494 completed one month, and 476 participants completed the three-month follow-up. Participants reported using the study salts nearly every day of the week and rated the taste of the salts similarly. Findings show that by the third month those in the substitute group had significantly lesser SBP by 4.6 mmHg and DBP by 1.1 mmHg. The substitute group also had a significant increase in 24-hour urinary potassium excretion of 0.24 g/d and a decrease in urinary sodium to potassium ratio of 0.71 compared to controls.
Based on their findings the study authors concluded, “The reduced sodium added potassium salt led to a substantial reduction in SBP in hypertensive patients, supporting salt substitution as an effective, low-cost intervention for BP lowering in rural India.”
“Our data suggest that using reduced-sodium, added potassium salt substitute to replace regular salt for home cooking will likely be an effective and scalable intervention for blood pressure control in rural India,” said Jason Wu, supervisor of the study and Associate Professor and Scientia Fellow at the George Institute.
“As none of the participants were aware of the existence of reduced-sodium salt at the beginning of the study, this suggests policymakers should consider supporting increased access to, and education about the use of such salt substitutes for hypertensive patients in India.”
