A recent editorial review summarizes the findings of a study examining a salt substitute on stroke outcomes.
A stroke occurs due to the interruption or disruption of blood, oxygen, and nutrients to the brain. A stroke can be classified as either an ischemic stroke, caused by the narrowing or blockage of an artery in the brain, or a hemorrhagic stroke, which occurs due to the leakage or rupture of a blood vessel in the brain. Severe strokes may lead to permanent neurological brain damage, and therefore quick and effective treatment is a top priority. The World Health Organization (WHO) estimates that the incidence of stroke will likely increase considering the continually changing demographics. As people begin to live longer and populations get older, there will be a larger number of individuals susceptible to strokes.
Traditional salt is made of sodium chloride (NaCl). Previous evidence from epidemiological studies has shown that a salt substitute, like potassium or magnesium-enriched salts, could reduce the risk of stroke. For instance, a previous study found that switching from regular salt to potassium-enriched salt was associated with a 41% reduction in cardiovascular mortality. Similar studies in animal models have demonstrated the neuroprotective effects of magnesium sulfate. However, studies investigating magnesium sulfate in acute-phase stroke patients are inconsistent and warrant further investigation.
Pan and colleagues conducted a randomized, double-blind clinical trial in Taiwan to investigate the effects of a traditional sodium salt (Na), potassium-salt (K salt), or potassium and magnesium-enriched salt (K/Mg salt) on neurological performance of stroke patients over a six-month period.
The scientists randomly assigned 291 patients to one of the three groups: regular salt (Na salt), K salt, or K/Mg salt. The researchers reported that patients in the K/Mg salt group, but not the K salt group, scored better on the impairment and disability scales, compared to the Na salt group. They subsequently concluded that salt substitution may be a viable option for improving stroke outcomes.
An editorial by Neal and colleagues, recently published in the Journal of American Clinical Nutrition in response to the study, argues that although the recruitment and randomization process utilized by Pan is reasonable, their rationale for the two intervention groups is unclear. More precisely, they don’t explain why a magnesium-alone group was not included to assess the effects of magnesium and potassium independently, as well as together. They also highlight that the large loss to follow-up (approximately 32%) could have introduced bias, which could alter the findings substantially.
Regardless of the concerns raised in this compelling editorial, both authors agree that a salt substitute may be a valuable strategy for improving outcomes in stroke patients. They hypothesize that salt alternatives likely confer their benefits by reducing blood pressure, a proven strategy for preventing recurrent strokes and associated morbidity. Moving forward, more careful studies are necessary to test this hypothesis and to clearly distinguish the effect of K salt, Mg salt, and K/Mg salt on stroke outcomes.
Written by Haisam Shah, BSc
Pan, W. H., Lai, Y. H., Yeh, W. T., Chen, J. R., Jeng, J. S., Bai, C. H., … & Hsiao, C. F. (2017). Intake of potassium-and magnesium-enriched salt improves functional outcome after stroke: a randomized, multicenter, double-blind controlled trial. The American Journal of Clinical Nutrition, ajcn148536.
Neal, B., & Wu, J. H. (2017). Salt substitution is a promising but unproven intervention for stroke management.