Sodium Reduction: How Big Might the Risks and Benefits Be?

Abstract

Cardiovascular diseases are the leading cause of death worldwide and raised blood pressure is the leading risk for these conditions. Excess sodium intake clearly elevates blood pressure though the association of sodium intake with cardiovascular outcomes has been disputed. Nonetheless, it was estimated that in 2017 excess dietary sodium caused between 1.4 and 5.4 million deaths. Key underlying assumptions for those estimates were that the association between sodium intake and cardiovascular disease is direct and linear, and that a daily consumption level of 2.0 g of sodium minimised risk. Recent data indicating that reported U-shaped associations of sodium with risk are the result of confounding provide strong support for the first assumption. Cardiovascular risks may, however, continue to decline below intake levels of 2.0 g per day. Further, because excess sodium intake appears to drive a progressive rise in blood pressure with age, the magnitude of the disease burden avoidable by sodium reduction may have been under-estimated. Regardless, health benefits will only be achieved if safe, effective and scalable interventions can be defined and none have been identified to date. Salt substitution, which switches regular salt for a reduced-sodium, added-potassium alternative offers a significant opportunity. Falls in blood pressure with salt substitution are comparable to single-drug therapy and salt substitutes are low cost, simple to use, well-tolerated and could be applied community-wide. Data that prove clinical benefits and exclude risks will be required to support widespread use. An ongoing large-scale randomised trial of the effects of salt substitution on stroke, major cardiovascular events and death will complete soon and define the role of salt substitutes in public health.

Keywords: Cardiovascular diseases; Review; Salt; Salt substitutes.