Introduction
Excess sodium intake contributes to elevated blood pressure and consequently cardiovascular disease. The recommended amount of salt is <5 g (less than a teaspoon) per day in adults.
Intervention
Replacing regular salt (sodium chloride) with a potassium-enriched, reduced-sodium alternative.
Indication
To reduce mortality and cardiovascular events in people with hypertension compared with the use of regular salt.
Precautions / Adverse effects
Potassium-enriched salt substitutes may be unsuitable for people at risk of hyperkalaemia such as those with chronic kidney disease.
Availability
Potassium-enriched salt substitutes, sometimes called ‘lite salt’ are available at major supermarkets.
Description
A systematic review and meta-analysis showed salt substitution reduced systolic blood pressure by 4.61 mm Hg and diastolic blood pressure by 1.61 mm Hg. Salt substitution reduced the risk of all-cause mortality by 11% and of cardiovascular mortality by 13%.1
The benefits are likely to be both from the reduction in sodium intake as well as the increased potassium intake.
The proportion of sodium chloride in the salt substitutes varied from 33% to 75%, and the proportion of potassium chloride varied from 25% to 65%. Each 10% lower proportion of sodium chloride in the salt substitute was associated with a 1.53 mmHg greater fall in systolic blood pressure and a 0.95 mmHg greater fall in diastolic blood pressure.1
No serious adverse effects associated with salt substitution were reported.1
While most of the trials were in people with hypertension, a subgroup analysis found no significant differences in outcomes based on hypertension status.2
Tips and Challenges
- Even incomplete replacement (~75%) of regular salt with potassium-enriched salt can lead to the reductions in mortality and cardiovascular events.3
- There is no or only a slight difference in taste between regular salt and potassium-enriched salt substitutes.
- Salt substitution can be an easier way of reducing dietary salt intake compared with making the behavioural change of salt abstinence. However, for many people, most of their salt intake comes from consuming processed or packaged foods.
Grading
Moderate (We are moderately confident in this research evidence, ie further research could have an important impact, which may change the estimates).