What pharmacists should know about saline substitutes

The attentive reader may recall at this point that in the study initiated by the Federal Ministry of Food and Agriculture, every second man and more than every third woman had a similarly high salt consumption of more than 10 g per day (1, 9).

In a recently published systematic review with meta-analysis, two independent reviewers searched the databases of Pubmed, Embase, Cochrane, among others, for randomized controlled trials in which salt substitutes such as KCl and co. had been investigated against no intervention or table salt for at least six months. Of the eight randomized trials included, seven took place in China or Taiwan. Six studies (n = 27,770) showed that the subjects who had used salt substitutes had a lower overall mortality rate than the control group (relative risk (RR) = 0.83, 95% confidence interval (CI): 0.73 to 0.95). A slightly reduced risk of severe cardiac complications (MACE, major adverse cardiac event) was also evident in three studies with a total of 23,215 subjects (RR = 0.85, 95% CI: 0.7 to 1.0) (10).

Are saline substitutes safe for normotensive people?

For a long time, there were only a few and controversial reports on how the use of salt substitutes affects normotensive people. A randomized study from China published a few weeks ago could shed more light on the matter. It is a post-hoc analysis of the Decide Salt study, a multicenter, cluster-randomized study with 48 nursing homes that were followed up for two years.

The evaluation was carried out on 611 subjects with a mean age of 71.4 years and a mean systolic blood pressure of 121.9 mmHg, diastolic 74.4 mmHg. The aim was to investigate how salt substitution in normotensive people affects the incidence of hypertension and hypotension. It was shown that the seniors who had used the salt substitute product (62.5% NaCl, 25% KCl, 12.5% ​​flavors and traces of amino acids) for seasoning had a significantly lower incidence of high blood pressure than those who had used normal table salt (11.7 vs. 24.3 per 100 person-years, adjusted hazard ratio (aHR) = 0.6, p = 0.02). At the same time, no increase in hypotension could be detected in the intervention group (9.0 vs. 9.7 per 100 patient-years, adjusted relative risk = 1.10).

Overall, there was no increase in mean systolic and diastolic blood pressure (-0.3 ± 11.9 and 0.2 ± 7.1 mmHg, respectively) in the salt replacement group, but there was an increase in the saline group (systolic +7.0 ± 14.3, diastolic 2.1 ± 7.5 mmHg). The authors conclude that salt replacement can reduce the risk of developing hypertension in elderly Chinese citizens without increasing the risk of hypotension (11).

Salt substitution is not yet common practice

Despite all these promising study results, salt substitution still does not seem to have become established in practice. In a review, scientists examined the extent to which the findings on the benefits and harms of potassium-containing salt substitutes have already been taken into account in existing guidelines.

The result was sobering. In the 32 hypertension guidelines and in the 14 chronic kidney disease guidelines examined, the recommendations were consistently inconsistent. The authors therefore recommend that the committees of the relevant guidelines review them and adapt them to the latest findings so that the use of salt substitutes is more widely implemented in the population (7).

In the high blood pressure guideline published last year by the European Society of Hypertension, the authors also see great potential in reducing salt and increasing potassium. However, they do not recommend salt substitutes, but rather point to a healthy diet with potassium-rich products such as apricots, bananas, carrots, various nuts and types of fish (12). |

^literature

^{(1) Salt intake in Germany: Results of the DEGS and KiGGS study, information from the Federal Ministry of Food and Agriculture, www.bmel.de/DE/themen/ernaehrung/gesunde-ernaehrung/degs-salzstudie.htmlas of March 2024}

^{(2) Those who save on salt prevent heart attacks and strokes, information from the Professional Association of German Internists, www.internisten-im-netz.de/aktuelle-meldungen/aktuell/wer-an-salz-spart-beugt-herzinfarkt-und-schlaganfall-vor.htmlas of 5 June 2007}

^{(3) Huang L et al. Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials. JM 2020:368:m315}

^{(4) Zidek, W. Can salt substitution or reduction replace medication in arterial hypertension? Internal Medicine 2022;63:1097-1104. https://doi.org/10.1007/s00108-022-01312-0}

^{(5) Does table salt substitute count as salt in the nutritional table? Information from the consumer advice centre, www.lebensmittelklarheit.de/fragen-antworten/zaehlt-kochsalzersatz-der-naehrwerttabelle-zu-salzas of June 10, 2022}

^{(6) Ditmer B. Diet salt – a healthy substitute for table salt. www.salze-online.de/diaetsalz.htmlaccessed on 11 April 2024}

^{(7) Xu X et al. Potassium-Enriched Salt Substitutes: A Review of Recommendations in Clinical Management Guidelines.Hypertension 2024;81:400-414, https://doi.org/10.1161/HYPERTENSIONAHA.123.21343}

^{(8) Salt replacement with potassium chloride appears to have benefits for the heart and blood vessels. Information from the Professional Association of German Internists, https://www.internisten-im-netz.de/aktuelle-meldungen/aktuell/salzersatz-mit-kaliumchlorid-hat-offenbar-vorteile-fuer-herz-und-gefaesse.htmlaccessed on 11 April 2024}

^{(9) Neal B et al. Effect of salt substitution on cardiovascular events and death. N Engl J Med 2021;385:1067-1077, DOI: 10.1056/NEJMoa2105675}

^{(10) Greenwood H et al. Long-term effect of salt substitution for cardiovascular outcomes: a systematic review and meta-analysis. Journal of Clinical Oncology 2020. https://doi.org/10.7326/M23-262}

^{(11) Zhang X et al. Effect of a salt substitute on the incidence of hypertension and hypotension among normotensive adults. Journal of the American College of Cardiology 2024;83(7):711-722}

^{(12) Mancia G et al. 2023 ESH Guidelines for the management of arterial hypertension The Task Force for the management of arterial hypertension of the European Society of Hypertension Endorsed by the International Society of Hypertension (ISH) and the European Renal Association (ERA), Journal of Hypertension 41(12) :p 1874-2071, December 2023. | DOI: 10.1097/HJH.0000000000003480}

^{(13) The original Maria Hilf Swedish tablets, information from Kolbpharma GmbH, www.schwedentabletten.deaccessed on 12 April 2024}

^{(14) Mariahilf-Apotheke Swedish tablets, information from Mariahilf-Apotheke Munich, https://mariahilf-apotheke.de/schwedentabletten/accessed on 12 April 2024}