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Low salt substitutes and cardiovascular health

Posted on 30th August 2022 by

Evidence Reviews
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In this blog, I will make a synopsis of the Cochrane Systematic Review Replacing salt with low‐sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women.

Introduction

Hypertension is a serious medical condition, extremely common in adults. It is one of the principal reasons people go to medical professionals and is a serious risk factor for developing heart failure, stroke, and chronic kidney disease, amongst others [1]. Thus, preventing and adequately following treatment, including non-pharmacological interventions, is important. One such lifestyle change, encouraged by the World Health Organization (WHO), is the reduction of salt intake, preferably to less than 5 grams per day [2].

What did the Systematic Review looked for?

In this Cochrane Review, the main objective was to see if replacing salt with low-sodium salt substitutes had any effect in cardiovascular health in specific populations, such as adults, pregnant women and children.

Low-sodium salt substitutes (LSSS) are products which, in order to be low in sodium, replace some of the sodium with an amount of potassium or any other mineral.

How did they do it?

They analysed 26 randomised controlled trials (RCTs), which had a total number of 34,961 adults and 92 children. The studied population had normal pressure, pre-hypertension or high blood pressure.  The outcomes evaluated were: changes in both diastolic and systolic blood pressure (DBP and SPB, respectively), hypertension, achieving blood pressure control, cardiovascular events, changes in serum potassium levels, changes in renal function, mortality and hypertension medication.

What were the results?

Of notice, the authors did not find any studies in pregnant women.

In regards to blood pressure, the group of adults consuming LSSS (compared to those consuming regular salt) experienced a reduction to some extent (mean difference of -2.43 mmHg in DBP and -4.76 mmHg in SBP).  Levels of serum potassium appeared to be slightly elevated (mean difference of 0.12 mmol) in the same intervention group. The events that probably reduced in the LSSS group are: non-fatal stroke, non-fatal acute coronary syndrome, and cardiovascular mortality. It may be necessary to mention that only 3 RCTs took into account those outcomes.

In respect to the other outcomes aforementioned, either low quality evidence or no difference when compared with the control group was found.  The studies in children only considered the effect of the intervention on DBP and SBP, and the authors of the review categorised this evidence as very uncertain.

Final conclusions

We cannot make conclusions with certainty about the safety or potential effects of the consumption of LSSS in adults with normal blood pressure, pregnant women and children. However, LSSS is probably a beneficial intervention in adults with hypertension. Although only 3 RCTs showed less incidence of non-fatal stroke, non-fatal acute coronary syndrome, and cardiovascular mortality, the authors comment that these may be a potential benefit if the intervention is in a much larger population

References

[1] Basile J, Bloch MJ. Overview of hypertension in adults. UpToDate. Web. July 2022.

[2]  World Health Organization. Hypertension.  Web. Published August 2021.


For full details of this Cochrane review, head to: Replacing salt with low‐sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women. You can also find an Editorial here: Cochrane Library Editorial: Low sodium salt substitutes, and an Evidently Cochrane blog here: Salt substitutes vs regular salt: a quick look.

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Carolina Guadalupe Cruz Muñoz

Mexican fourth-year medical student from the Universidad de Guadalajara. I´m passionate about science, mental health, epidemiology, evidence-based medicine and sharing about the importance of shared decision making. View more posts from Carolina Guadalupe

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