This research reviewed ten studies and included 1119 participants with high blood pressure where salt substitutes were used instead of regular salt (Jafarnejad S, et.al., 2020). Potassium chloride is used at least partially instead of regular salt in salt substituted products.
The results showed a significant reduction in systolic blood pressure of 8.87 mm Hg and a reduction of diastolic pressure of 4.04 mm Hg.
This is another study also investigating the effect of salt substitutes on systolic and diastolic blood pressure where several articles were reviewed (Peng YG, et.al., 2014). It included 1974 participants without high blood pressure.
The researchers found that systolic blood pressure was on average reduced with 4.9 mm Hg and diastolic blood pressure with 1.5 mm Hg.
This showed that salt substitutes can be an effective way of preventing high blood pressure.
Sadegh Jafarnejad, Hamed Mirzaei, Cain C T Clark, Mohsen Taghizadeh, Armin Ebrahimzadeh, The hypotensive effect of salt substitutes in stage 2 hypertension: a systematic review and meta-analysis, BMC Cardiovasc Disord. 2020 Feb 27;20(1):98.
Peng YG, Li W, Wen XX, Li Y, Hu JH, Zhao LC. Effects of salt substitutes on blood pressure: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2014 Dec;100(6):1448-54.