1st Revision: Isobel Lester Based on a paper “Effect of Salt Substitution on Cardiovascular Events and Death”
By: Murielle Nsiela
Excessive consumption of salt (also known by the scientific name sodium chloride) and low intake of dietary potassium, is linked with increased blood pressure, cardiovascular disease, and premature death1,2,3. Previous studies4 have shown that decreasing dietary sodium and increasing potassium has some blood pressure lowering effects5.
Salt substitutes usually replace part of the sodium chloride with potassium chloride in a single product7. These salt substitutes are in multiple countries worldwide and have shown blood pressure lowering effects in various populations6.
Sadly, reliability of the effects of salt substitutes on diseases such as acute coronary syndrome and stroke is poor at the moment. Also, it is important to consider the theoretical risks of hyperkalaemia (high blood potassium) and sudden death linked to salt substitutes in participants with kidney disease.
The study mentioned at the beginning aimed to explain the overall benefits and risks of salt substitutes compared to regular salt concerning cardiovascular events, stroke, death, and clinical hyperkalaemia.
The study was carried out throughout five years. It only involved adult men and women who were 60 years and older, or either had a history of stroke and/or had poorly controlled blood pressure. In addition, participants were excluded from the study if:
- they could not consume the salt substitute used in the study,
- were taking medications that increased potassium levels in the blood,
- had severe kidney disease,
- were taking potassium supplements.
- ate most meals out (did not prepare their meals themselves)
- were unlikely to survive longer than 6 months.
The study was conducted in 600 villages in five provinces in China. The villages were divided into 2 groups, the intervention group which took the salt substitute composed of 75% sodium chloride and 25% potassium chloride, and the control group which consumed regular salt.
The study’s results showed that the salt substitute group had a lower rate of fatal and non-fatal stroke events as opposed to the group taking regular salt. The data showed 29.14 stroke events with the salt substitute group and 33.65 stroke events with the normal salt group.
Salt substitute group also showed more protection against cardiovascular events, with 49.1 events recorded for the salt substituted group and 56.3 events for the regular salt group. One could say the differences do not seem that big, but it is still a difference that should not be ignored.
In addition, deaths caused by other factors showed 39.3 events for the salt substitute group and 44.6 for the regular salt group. The results regarding hyperkalaemia showed no significant difference amongst the 2 study groups8.
In conclusion, the study has shown that using substituted salt instead of regular salt can decrease the chances and risks of cardiovascular events, stroke and potentially death. The authors suggest that using a salt substitute would also benefit individuals in Asia, Latin America, and Africa due to their high salt consumption.
References:
- Cogswell ME, Mugavero K, Bowman BA, Frieden TR. Dietary sodium and cardiovascular disease risk — measurement matters. N Engl J Med 2016; 375: 580-6.
- Aburto NJ, Hanson S, Gutierrez H, Hooper L, Elliott P, Cappuccio FP. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ 2013;346: f1378.
- Aburto NJ, Ziolkovska A, Hooper L, Elliott P, Cappuccio FP, Meerpohl JJ. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ 2013; 346: f1326.
- Huang L, Trieu K, Yoshimura S, et al. Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials. BMJ 2020; 368: m315.
- Filippini T, Naska A, Kasdagli M-I, et al. Potassium intake and blood pressure: a dose-response meta-analysis of randomized controlled trials. J Am Heart Assoc 2020; 9(12): e015719.
- Greer RC, Marklund M, Anderson CAM, et al. Potassium-enriched salt substitutes as a means to lower blood pressure: benefits and risks. Hypertension 2020; 75: 266-74.
- Yin X, Liu H, Webster J, et al. Availability, formulation, labelling, and price of low-sodium salt worldwide: environmental scan. JMIR Public Health Surveill 2021; 7(7): e27423.
- Neal B, Wu Y, Feng X, Zhang R, Zhang Y, Shi J, Zhang J et al. Effects of Salt substitutions on Cardiovascular events and death. The New England Journal of Medicine. 2021;385(12):1067-1077.
