EffectivenessandFeasibilityofTaxingSaltand FoodsHighinSodium:ASystematicReviewofthe Evidence

Abstract

Dietshighinsaltarealeadingriskfordeathanddisabilityglobally.Taxingunhealthyfoodisaneffectivemeansofinfluencingwhatpeopleeatand improvingpopulationhealth. Althoughthereisagrowingbodyofevidenceontaxingproductshighinsugar,and unhealthy foodsmorebroadly, there is limited knowledge or experience of using fiscal measures to reduce salt consumption. We searched peer-reviewed databases [MEDLINE, Embase,CochraneCentralRegisterofControlledTrials(CENTRAL),andtheCochraneDatabaseofSystematicReviews]andgrayliteratureforstudies published between January 2000 and October 2019. Studies were included if they provided information on the impact on salt consumption of: taxesonsalt;taxesonfoodshighinsalt,andtaxesonunhealthyfoodsdefinedtoincludefoodshighinsalt.Studieswereexcludediftheirdefinition ofunhealthyfoodsdidnotspecifyhighsaltorsodium.Wefound18relevantstudies,including15studiesreportingtheeffectsofsalttaxesthrough modeling (8), real-world evaluation (4), experimental design (2), or review of cost-effectiveness (1); 6 studies providing information relevant to country implementation of salt taxes; and 2 studies reporting stakeholder perceptions toward salt taxation. Although there is some evidence on the potential effectiveness and cost-effectiveness of salt taxation, especially from modeling studies, uptake of salt taxation is limited in practice. Some modeling studies suggested that food taxes can have unintended outcomes such as reduced consumption of healthy foods, or increased consumption of unhealthy, untaxed substitutes. In contrast, modeling studies that combined taxes for unhealthy foods with subsidies found that the benefits were increased. Modeling suggests that taxing all foods based on their salt content is likely to have more impact than taxing specific products high in salt given that salt is pervasive in the food chain. However, the limited experience we found suggests that policy-makers favor taxingspecificproducts.