Should we recommend low sodium salt substitutes? by Katy Stuart, RD

On 30th January this year, the World Health Organisation (WHO) published a guideline on the use of low sodium salt substitutes (LSSS). In its summary, it recommends that governments consider promoting the use of LSSS to help dietary salt reduction and reduce the risk of hypertension and cardiovascular disease.(1,2) As a renal dietitian, I was interested in reading the report, as I have concerns about recommending potassium containing LSSS to the general population. The report does point out that LSSS are not suitable for those with kidney disease, but what about those who have undiagnosed kidney disease?

Consuming too much salt in our diets is a significant problem worldwide, and on average, we are consuming 10g per day.(1) This is nearly double the WHO recommendation of <6g per day.(2) A high salt intake is linked to hypertension and increased risk of cardiovascular disease, stroke and kidney disease.(3) The death rate from CVD alone is 31% worldwide.(3) The use of LSSS instead of salt is an effective way of reducing salt intake while still providing the ‘salt’ taste that people are used to.(2)

What are LSSS?

LSSS are manufactured to contain potassium chloride instead of sodium chloride.(3) Potassium chloride resembles the physical and functional properties of sodium chloride.(11) For most people, naturally occurring potassium salt is not dissimilar to sodium chloride in taste.(3) However, some may find the taste bitter and metallic..(3,4) LSSS commonly contain around 65% sodium chloride, 25% potassium chloride and 10% magnesium sulphate.(11)

BENEFITS OF POTASSIUM

Increasing potassium intake has been shown to reduce the risk of CVD and hypertension and reduce the rates of premature death.(6-8,11) However, many health initiatives designed to target salt intake have not resulted in reduction, and most countries will not meet WHO’s target of cutting sodium intake by 2025.(8) WHO have reset this target for 2030.(8)

The WHO report

The WHO report is based on clinical evidence from a systematic review of 26 randomised controlled trials (RCTs) (from 1986-2021.)(1) After examining all the evidence and weighing up the risks versus benefits, WHO concluded the following recommendations:(5)

  • Salt manufacturers around the world should change to producing and marketing LSSS.

  • Government policies are required to promote LSSS and discourage regular salt use.

  • People should be encouraged to cook, season and preserve foods using LSSS over regular salt.


The WHO recommendations apply to ‘discretionary’ salt, which is the salt people add to their food or in cooking.(2) However, LSSS are increasingly being used in processed foods, providing a further source of dietary potassium in the form of potassium additives.(1) This raises the concern regarding potassium intake, which may have harmful effects for those with kidney impairment.(9,10)

CONCERNS RAISED ABOUT LSSS

People with kidney impairment are not able to excrete potassium normally, and high intakes of potassium can lead to hyperkalaemia, in turn causing cardiac arrhythmia and cardiac arrest if untreated.(9,10)

WHO acknowledges the hyperkaliaemic risks of LSSS: “…settings where a considerable proportion of the population may have undiagnosed kidney disease for which it would not be advisable to increase potassium intakes”.(1)

WHO points out, though, that few of the studies included actually reported on hyperkalaemia and the studies that did were variable in quality.(1) Some studies reported that using LSSS instead of regular salt led to a “mean increase of 0.12 mmol/L in the level of potassium in the blood (moderate certainty evidence.)” Although a small increase, this is potentially harmful for some people.(1)

WHO also agree that there is “uncertainty about the balance between the benefits and potential harms” and I agree with this.(1) Although LSSS are not being recommended to those with impaired kidney function, those with hypertension, CVD and diabetes may well have undiagnosed kidney impairment and high intake of potassium from LSSS and processed foods with added potassium is a more significant risk.(6,9,10)

Additional risk is present from some medications that increase potassium levels, including angiotensin-converting enzyme inhibitors (ACEs), angiotensin 2 receptor blockers (ARBs) and spironolactone.(9,10)

It is questionable whether the results of the larger studies apply to the UK, as diet and lifestyle in rural China are different to other countries.5 Also, the study participants included were those with a previous history of stroke or people 60 years or over with already poorly-controlled high blood pressure.(5)

As well as CKD, WHO’s guidance does not extend to children and pregnant women, as currently, there is not enough data to recommend LSSS for these groups.(1)

Another factor to consider is cost. LSSS are more expensive than regular salt, and this could affect the public’s willingness to switch over to them.(1) 

The food industry and LSSS

Potassium salts are frequently used in food manufacturing and more and more products are on the market now containing potassium additives, such as crisps, corn/maize snacks, soft drinks, instant noodles, cooked meats and baked goods.(3) This is due to the limits put on the reformulation of products, which have to contain less sodium chloride without impacting the taste consumers are used to.(3,5) This is concerning for renal dietitians, as we are trying to help those with kidney impairment to reduce their potassium intake and this is difficult if people need to rely on processed foods.

In 2016, Unilever (whose products include Pot Noodles, Walls ice cream, Knorr soups and stock cubes) conducted a study to review the impact of adding potassium chloride in place of sodium chloride to help consumers reduce their salt intake. Their findings concluded that the use of LSSS in food manufacturing would result in better compliance with the WHO guidelines on potassium intake.(3) It seems likely that food manufacturers will continue to replace sodium chloride with potassium chloride where possible, and those with kidney impairment will struggle to make food choices that are low in potassium.

Conclusion and considerations

One way to protect at-risk groups from exposure to LSSS is to ensure that food products are appropriately labelled and have warnings.(8) Products containing potassium additives should declare this in the ingredients, and renal dietitians can advise on what to look out for on food labels.

On balance, the WHO guidelines help underpin current health eating guidance, which encourages people to reduce their salt intake. The reduction in sodium chloride in processed foods does favour better outcomes for many.(1) However, it is better to reduce overall dietary salt content by choosing to cook from fresh and reduce the intake of processed foods. Many other ingredients can be used to provide taste, such as garlic, herbs, onion powder, nutritional yeast, spices, etc.(4) I would advise those with medical conditions who wish to use LSSS to check with their doctor or dietitian first to ensure safety.(11)

Katy has 20 years of experience in both acute nutrition support and renal dietetics. she is now a full-time Renal Dietitian at Pilgrim Hospital,
Boston, Lincs.

Katy Stuart, RD, Renal Dietitian

References

  1. World Health Organisation, 2025 Use of lower-sodium salt substitutes: WHO guidelines: https://www.who.int/publications/i/item/9789240105591

  2. Resolve to Save Lives, 2025 . https://resolvetosavelives.org/about/press/the-george-institute-for-global-health-and-resolve-to-save-lives-welcome-whos-recommendation-to-replace-regular-table-salt-with-lower-sodium-salt-substitutes/#:~:text=The%20World%20Health%20Organization's%20(WHO,blood%20pressure%20and%20cardiovascular%20disease

  3. Farrand C, MacGregor G, Campbell N, Webster J (2019). Potential use of salt substitutes to reduce blood pressure Journal of Clinical Hypertension (Greenwich). Jan 28;21(3):350-354. https://pmc.ncbi.nlm.nih.gov/articles/PMC8030351/

  4. The Science of Health, Salt Substitutes: A Healthy Alternative to the Real Thing? (2023). www.uhhospitals.org/blog/articles/2023/06/salt-substitutes-a-healthy-alternative-to-the-real-thing#:~:text=Salt%20substitutes%20can%20raise%20blood%20potassium%20levels,angiotensin%2Dconverting%20enzyme%20(ACE)%20inhibitors%20and%20potassium%2Dsparing%20diuretics

  5. British Heart Foundation, Would switching to a salt substitute reduce stroke, heart attacks and deaths? www.bhf.org.uk/informationsupport/heart-matters-magazine/news/behind-the-headlines/salt-substitute

  6. Brand A, Visser M, Schoonees A, Naude C. Replacing salt with low-sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women, 2022, Cochrane Database Syst Review Aug 10;8(8):CD015207. https://pubmed.ncbi.nlm.nih.gov/35944931/

  7. Health Line, Swapping Salt with Substitutes May Lower Your Risk of Death from Heart Disease, 2024. www.healthline.com/health-news/salt-substitutes-heart-disease-risk

  8. The Conversation, Why the WHO has recommended switching to a healthier salt alternative, 2025. https://theconversation.com/why-the-who-has-recommended-switching-to-a-healthier-salt-alternative-248436#:~:text=This%20week%20the%20World%20Health,for%20substitutes%20containing%20less%20sodium

  9. Everyday Health, Why the WHO has recommended switching to a healthier salt alternative, 2025. https://www.everydayhealth.com/kidney-diseases/are-salt-alternatives-dangerous-for-people-with-kidney-disease/

  10. Doorenbos C, Vermeij C (2003). Danger of salt substitutes that contain potassium in patients with renal failure, BMJ. 2003 Jan 4;326(7379):35-36. https://pmc.ncbi.nlm.nih.gov/articles/PMC1124926/

  11. Cleveland clinic Health Essentials, Diet, Food & Fitness/Nutrition. Are Salt Substitutes a Healthy Way to Lower Your Sodium Intake?, 2021  https://health.clevelandclinic.org/are-salt-substitutes-a-healthy-way-to-lower-your-sodium-intake


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