The World Health Organisation recently released guidelines on lower-sodium salt substitutes – the guidelines being shaped by crucial findings from a Cochrane systematic review conducted by Stellenbosch University’s Centre for Evidence-based Health Care (CEBHC).
Eight million deaths worldwide are annually attributed to poor diet, with about 2m linked specifically to high sodium consumption, a primary component of table salt.
Reducing sodium intake effectively decreases the risk of non-communicable diseases, including heart disease and chronic kidney disease, while also lowering the likelihood of conditions such as gastric cancer.
The university’s team, which was commissioned by the WHO’s Department of Nutrition and Food Safety, was led by Professor Celeste Naude, a registered dietician from CEBHC, who served as senior author. Dr Amanda Brand served as first author, with Dr Marianne Visser and Anel Schoonees contributing as co-authors. Professor Razeen Davids, Head of SU's Division of Nephrology, provided specialised clinical expertise.
Healthier alternative for some
Lower-sodium salt substitutes (LSSS) offer an alternative to conventional table salt by reducing sodium content through partial replacement with other minerals, predominantly potassium chloride. This substitution helps mitigate health risks associated with regular salt consumption, as high sodium and low potassium levels contribute to elevated blood pressure.
However, potassium-containing LSSS present potential health risks, particularly the risk of hyperkalaemia (elevated blood potassium), which can affect heart rhythm and rate. These risks are particularly significant for individuals with compromised kidney function, or other circumstances or conditions where potassium excretion is hampered.
“Our review examined the most robust evidence regarding LSSS' effects on blood pressure and cardiovascular risks, compared to regular salt, while also evaluating safety considerations,” Naude said.
Brand detailed the extensive review process: "We analysed five electronic databases and trial registries, screening approximately 6 000 records to identify 26 relevant randomised controlled trials involving 34 961 adults and 92 children. We consolidated and evaluated the findings, assessing our confidence in the combined evidence based on factors such as methodological rigour and study size.”
The process was overseen by a WHO guideline development group.
Balancing benefits and harm
While evidence demonstrated positive effects on blood pressure and cardiovascular risks, safety data remained limited. This created uncertainty regarding the balance between benefits and potential risks, particularly in regions where many individuals may have undiagnosed conditions contraindicating increased potassium intake, such as in resource-limited settings.
The WHO recommendation on the use of lower-sodium salt substitutes:
• “To reduce blood pressure and risk of cardiovascular diseases, WHO has recommended reducing sodium intake to less than 2 g/day (strong recommendation). In this context, using less regular table salt is an important part of an overall sodium reduction strategy.
• If choosing to use table salt, WHO suggests replacing regular table salt with lower-sodium salt substitutes that contain potassium (conditional recommendation).
• This recommendation is intended for adults (not pregnant women or children) in general populations, excluding individuals with kidney impairments or with other circumstances or conditions that might compromise potassium excretion."
The WHO emphasised the conditional nature of the LSSS recommendation, which requires implementers to evaluate key considerations before adoption, particularly regarding safety monitoring for elevated blood potassium levels.
This conditional approach allows individual countries and regions to assess their circumstances and develop appropriate implementation strategies.
“Contributing to these significant global guidelines aligns with CEBHC’s mission of conducting impactful research and supports the university’s strategic Vision 2040,” Naude said.
WHO guidelines (Creative Commons Licence)
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