S-54-1: SUBSTITUTING THE WORLDS SALT SUPPLY

Abstract

The adverse effects of excess dietary sodium intake on blood pressure levels are well-established. On average the world eats dietary sodium, mostly in the form of salt, at twice the level recommended by the World Health Organization and five times the level consumed during a million years of hominid evolution. At the same time, average dietary potassium intake is below recommended intake levels in many populations, and inadequate potassium intake is also associated with high blood pressure. Potassium-enriched salt substitute, in which some of the sodium chloride is replaced with potassium chloride, was first showed to lower blood pressure more than a decade ago. Most recently, in 2021, the Salt Substitute and Stroke Study showed that potassium-enriched salt can also reduce the risks of stroke (rate ratio 14%; p = 0.006), major cardiovascular events (13%; p < 0.001) and premature death (12%; p < 0.001). This large-scale randomised trial done amongst 21,000 individuals followed for 5 years also showed that these benefits were achieved without harm, and in particular, with no evidence of hyperkalemia (rate ratio 1.04; p = 0.76). Potassium-enriched salts are a pragmatic means of reducing dietary sodium intake and supplementing dietary potassium intake in parallel. Unlike many other sodium reduction strategies, they are easy to implement because potassium-enriched salt can be used in just the same way as regular salt. This provided for excellent adherence in the Salt Substitute and Stroke Study, with 93% of participants still using the salt substitute at the end of the study. The potential health gains from a switch to potassium-enriched salt are very large. Modelling done for China indicates that about 1 million strokes and heart attacks could be prevented each year if the switch was made nationwide. Several million more events might be averted if implementation was global. Another key feature of potassium-enriched salt is that it can be provided at low cost. While on average about twice as expensive as regular salt, potassium-enriched salt has a median price of less than $3 per kilogram in low- and middle-income countries. Over the last 50 years, the fight against iodine deficiency disorders has seen the global salt supply switched from salt to iodized salt. It is now time to make a second switch from iodized salt to iodized and potassium-enriched salt to also prevent blood pressure related diseases.