A reduced-sodium added-potassium salt substitute is sometimes used to supplement a sodium-restricted (reduced salt) diet to help treat hypertension. Such salt substitutes typically contain a reduced amount of sodium chloride and an added amount of potassium chloride, and randomized controlled trials show that they can effectively reduce blood pressure.[1][2][3][4][5] However, this does not mean that more is better — some evidence shows that supplementation with potassium salts in high doses might increase blood pressure.[6]
Because high blood pressure increases the risk of cardiovascular disease and stroke-related mortality, it is possible that the blood-pressure-lowering effect of a reduced-sodium added-potassium salt substitute could reduce mortality risk. Some current evidence supports this hypothesis,[1][2][7] but due to the dearth of studies and the large between-study variability, further long-term high-quality observational studies and randomized controlled trials are needed to make firm conclusions.