Taxation of Salt and Foods High in Sodium
A new systematic review (1) looking at the effectiveness and feasibility of taxing salt and foods high in sodium was highlighted in Salt in the News
(June 2020) from World Action on Salt & Health.
The systematic review included eighteen studies found between 2000 and 2019 (1). Fifteen of the studies reported on the effects of salt taxes: eight looked at taxing salt itself, foods high in salt and unhealthy foods (modelling studies, based on estimates of what the effects would be); four looked at the impact of salt taxation (real-world evaluation); two looked at price and subsides (experimental design/simulated online grocery stores); and one looked at cost-effectiveness of taxation (a review). Six of the 18 studies provided information relevant to country implementation of salt taxes and two of the 18 studies reported stakeholder perceptions toward salt taxation.
The authors found that the actual practice of salt taxation is limited (1). Three of the four real-world evaluation studies, mostly gray literature, did not report a measure of uncertainty (e.g. 95%CI or SE) and the two simulation studies showed wide confidence intervals, raising questions about the precision of the study results. Relying mostly on the modelling studies and noting that the studies varied in magnitude and range of measures (making them difficult to compare and summarize), the authors provided the following key summary points:
- There is some indication of potential effectiveness and cost-effectiveness of salt taxation.
- Taxation of food can have unintended outcomes, such as the decreased consumption of healthy foods or an increased consumption of other unhealthy, untaxed substitutes.
- When taxes for unhealthy foods were combined with subsidies towards heathy foods, the benefits were increased.
- Taxing all foods based on their salt content (broader application) is likely to have more impact than taxing only specific products high in salt and minimizes opportunity for substitution for other high sodium foods.
High salt diets (more than 5 g/day for adults (2)) are considered a leading dietary risk for death and disability globally (3). Continued research on population sodium reduction strategies (4) and other fiscal strategies, such as taxation, is needed to help reduce salt consumption.
- Dodd R, Santos JA, Tan M, Campbell NR, Mhurchu CN, Cobb L, et al. Effectiveness and feasibility of taxing salt and foods high in sodium: a systematic review of the evidence. Adv Nutr. 2020 Jun 20;nmaa067.doi: 10.1093/advances/nmaa067. Available from: https://pubmed.ncbi.nlm.nih.gov/32561920/
- World Health Organization. WHO guideline: sodium intake for adults and children. Geneva, Switzerland: WHO Press; 2012. Available from: https://apps.who.int/iris/bitstream/handle/10665/77985/9789241504836_eng.pdf;sequence=1
- GBD 2017 Diet Collaborators. Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the global burden of disease study 2017. Lancet. 2019;393(10184):1958-72. Available from: https://pubmed.ncbi.nlm.nih.gov/30954305/
- WHO. Global strategy on diet, physical activity and health. Population sodium reduction strategies. [cited 2020 Jul 23]. Available from: https://www.who.int/dietphysicalactivity/reducingsalt/en/