Interventions
The following sections address high-impact interventions for sodium reduction.
Overall Summary of Interventions
High impact sodium reduction strategies are ones that are (1) scalable and sustainable, (2) have evidence of effectiveness or if there is no strategy proven effective for a particular source of sodium, be an innovative and promising approach, and (3) have a large potential benefit. To demonstrate evidence of effectiveness, the strategy must either be rigorously evaluated with demonstrated success in sodium reduction, provide suggestive evidence of effectiveness from lower quality evaluation or modeling studies or be rigorously evaluated strategies that do not specifically target sodium reduction but can be applied to sodium reduction. Seven strategies were found that met the three framework criteria. For reducing sodium in packaged food: front-of-pack labeling, packaged food reformulation targets, regulating marketing to children, and taxation on high sodium food. For reducing sodium consumed at home: mass media campaigns and population uptake of low-sodium salt. For reducing sodium consumed outside the home: food procurement policies for public institutions. Governments should concentrate on the highest-impact strategies and take a multi-component approach to addressing excess sodium consumption as no single strategy is enough to reach the WHO goal of 30% reduction in sodium intake by 2025.
Since 2014, there has been a significant increase in policies to reduce sodium intake, although much progress is still needed to meet the goal of a 30% reduction of population sodium intake by 2025. This article, an update to a previously published systematic review in 2015, identified all current national salt reduction initiatives around the world as of 2019. This review reported national salt reduction initiatives increased globally by 28% (96 national initiatives in 2019), although no changes were seen in Africa or Southeast Asia where initiatives remain limited. Despite progress, no countries were found to have met the target set for 2025, demonstrating an urgent need for accelerated efforts. There was a reported increase in interventions in settings (such as schools or food outlets), food reformulation, consumer education, front-of-pack labeling, and salt taxation. Education initiatives decreased by 30%, representing a shift from one-time campaigns to more integrated, regulatory approaches. More countries have reported evaluation data on salt intake or other measures; however, further data is needed, especially on salt intake, as many available data are outdated or not collected using gold standard measurement methods.
This Cochrane review assessed the impact of population-level sodium reduction interventions in 10 countries with adequate data. Five countries showed a mean decrease in salt intake from before to after intervention (China, Finland (Kuopio area), France, Ireland, UK), ranging from -1.15g/day in Finland to -0.35g/day in Ireland. Two initiatives resulted in a mean increase in salt intake (Canada, Switzerland). Of the seven multicomponent interventions that were structural in nature (targeting environments rather than directly targeting behavior change, e.g. reformulation or procurement policies), four showed a mean decrease in salt intake. The overall quality of evidence rating was “very low”. Only 10 of the 75 countries with sodium reduction initiatives originally identified provided sufficient data for quantitative analysis, demonstrating limited monitoring of sodium reduction initiatives (or a limited data infrastructure in general).
This systematic review including 70 studies shows that comprehensive, multi-component strategies that use “upstream, structural” policy-based population approaches (e.g., mandatory reformulation) generally achieve the largest reductions in population-wide salt consumption. When assessed separately, “mandatory reformulation alone could achieve a reduction of approximately 1.45g/day (three separate studies), followed by voluntary reformulation (-0.8g/day), school interventions (-0.7g/day), short term dietary advice (-0.6g/day) and nutrition labelling (-0.4g/day), but each with a wide range”. Smaller reductions were seen for taxation, community-based counseling, health education media campaigns, and worksite interventions.
Based on a review of literature published between June 2013-February 2020, the main salt reduction interventions conducted in low- and middle-income countries were education, food reformulation, and salt substitution. The study focused on four main outcome measures– salt intake; sodium levels in foods; knowledge, attitudes, and behaviors (KABs) towards salt; and blood pressure. In the majority of outcome categories, interventions had a positive effect: 12/17 reported a reduction in salt intake, 17/19 reported improvements in KAB, 6/6 reported lower sodium levels in foods or showed compliance of sodium levels with agreed targets, and 10/14 reported a decrease in blood pressure. RCTs on these interventions measured changes in 24-hour urine, reporting sodium intake reductions ranging from 0.4 to 3.8 g/day, and systolic blood pressure changes from −10.1 to 1.8 mmHg. More population level research is needed as many of the studies were small scale and targeted population subgroups.
Industry Reformulation
Added November 2022: Rosewarne E, Santos JA, Trieu K, et al. A Global
Review of National Strategies to Reduce Sodium Levels in Packaged Foods. Adv Nutr. 2022.
Though processed food reformulation is identified as one of WHO’s ‘best buys’ for sodium reduction, only a third of countries have implemented this core strategy globally, and limited evaluation of these strategies post-implementation. As of December 2019, 62 countries have reformulation strategies in place to reduce sodium in packaged foods, but only 19 of those include evaluation. Some countries (19) had only industry engagement strategies, including 12 with voluntary agreements with industry, 5 that held industry meetings, and 2 that used both approaches. 24 additional countries had reformulation strategies planned but not yet implemented. The main strategy was the use of sodium targets, which are in place in 43 countries either on a mandatory basis (9 countries), voluntary basis (28 countries), or both (6 countries). Nearly all set maximum targets, with a small number using average targets or sales-weighted average targets. = The number of categories that countries set targets for varied widely, ranging from 1 to 150. A common limitation was that targets were often set for only one category (often bread), limiting the impact on the food supply. When mapped to the WHO sodium benchmarks, large variations were found in the targets set by each country, suggesting a lack of cohesion in global efforts. The study found no substantial difference in impact of mandatory and voluntary targets on the food supply, though it is worth noting that only about 30% of countries with strategies had evaluation programs in place.
This paper proposes “a step-by-step approach to setting and implementing targets for salt levels in foods for LMICs, which can then be used for voluntary or mandatory policy interventions.” The five main steps are: 1) identifying the main sources of salt in the diet, 2) selecting foods for salt targets, 3) setting target levels in foods, 4) identifying strategies for engagement with stakeholders and 5) establishing mechanisms for monitoring. Multiple implementation strategies for each step exist, and a hierarchy of “the most to least desirable based on validity and methodological strength” is provided for each step. Salt targets can be used not only for directly regulating the sodium content in processed foods, but also to implement labeling, food procurement, and taxation policies.
This systematic review found that reformulated products were generally accepted by consumers (based on sales/purchases or market-share). 90% of the 59 studies reported reduced-sodium products to have positive acceptability. 73% of studies saw improved nutrient intakes, with meta-analysis finding a -0.57g/day reduction per day in salt intake attributed to reformulation. Notably, compensation (defined as either overconsumption or as a change in dietary patterns such as a switch towards non-reformulated products) with reduced salt reformulated products did occur, but often it did not offset the benefits of reformulation. Abrupt formulation interventions led to more compensation than cases when reformulation was done more gradually, in a silent manner.
Added November 2022: Dunteman AN, McKenzie EN, Yang Y, et al. Compendium of sodium reduction strategies in foods: A scoping review. Compr Rev Food Sci Food Saf. 2022 Mar;21(2):1300-1335.
Reducing sodium in the food supply is a key strategy for overall population sodium reduction, particularly in countries where packaged food is a significant source of sodium. This scoping study reviewed 277 primary studies assessing methods to reduce sodium content in food products, and identified multiple strategies to reduce sodium in foods while maintaining acceptable sensory qualities. Included studies were conducted primarily in Europe and the Americas (79%). The use of salt replacers (primarily using other mineral salts, especially potassium chloride) was the most common method to reduce the sodium content of foods (n=117), followed by salt removal (n=113) (reducing added salt, step-by-step reductions), flavor modification (n= 86) (e.g., using umami ingredients, glutamates, amino acids and peptides, herbs and spices), physical modification (n=63) (e.g., color, salt crystal structure, size, and distribution, texture modification, processing), and functional modification (n=20) (e.g., binders, preservatives, meat extenders). Each of these methods is described in detail in the article. Cured meats were the most commonly studied food, followed by breads, rolls, and tortillas, as well as non-cured meats and cheese. This review demonstrates the feasibility of sodium reduction in foods; however, there is more research is needed, particularly regarding (1) combining methods, especially salt replacement with functional modification and salt replacement with physical modification; (2) approaches in categories not commonly looked at (e.g., snack foods, condiments, and mixed dishes) or in products where salt is primarily utilized for its functionality (e.g., bread); (3) consumer perceptions and which approaches would be most acceptable in specific populations; and (4) whether the technological impact of sodium reduction is correlated strongly to sensory quality characteristics.
For similar articles, see:
Vinitha K, Sethupathy P, Moses JA, Anandharamakrishnan C. Conventional and emerging approaches for reducing dietary intake of salt. Food Res Int. 2022 Feb;152:110933.
Front of Pack Labeling
This systematic review assessed the impact of front-of-pack labelling for food and non-alcoholic drinks on purchasing and consumption of prepackaged foods. A meta-analysis of 14 studies including information on purchasing and consumption showed significant reductions in the content of sodium (-24.5mg per 100g) and sugar (-0.40g per 100g) in purchased products with a front-of-pack label compared to products with no label and non-significant reductions in energy and saturated fat content. In terms of particular types of labels, “high in” warning labels significantly reduced purchase content of energy, sugar, and sodium; multiple traffic light labels decreased sodium content with a trend towards reduction in the purchase content of saturated fat, and the health star rating scheme did not show significant findings. The findings suggest that front-of-pack labels, particularly interpretive models like “high in” warnings, improve the health of food purchases.
For similar articles, see:
Song J, Brown MK, Tan M, et al. Impact of color-coded and warning nutrition labelling schemes: A systematic review and network meta-analysis. PLoS medicine. 2021 Oct 5;18(10):e1003765.
The guidance document provides advice for governments, researchers, civil society groups, and other stakeholders who are involved with the design and development of front-of-pack nutrient labels. These labels are a highly effective mean of communication with consumers at the point of decision-making and purchase. They help consumers identify unhealthy foods and make healthier choices, improve dietary intake, reduce diet-related NCDs, and can also stimulate healthier food production and product reformulation. The guide outlines strategies for research, communication, and development of front-of-pack labels. Governments seeking to implement front-of-pack labels should follow these steps: define the public health problem; determine scientific criteria for labels; review existing labels for other settings for use in the local context; engage civil society; form an expert advisory committee; build public support; test label designs and identify an effective label; develop graphic design guidelines for implementing labels; and evaluate policy impact.
For similar document, see:
World Cancer Research Fund International. Building momentum: lessons on implementing a robust front-of-pack food label. 2019.
This scoping review describes a conceptual model for how front-of-pack warning labels affect consumer behavior, examines which outcomes are currently measured in the literature, and reviews the existing evidence on front-of-pack warning labels from randomized control experiments. The conceptual model for how nutrient warnings change behaviors includes attention to the label; comprehension, cognitive elaboration, and message acceptance; eliciting a negative affect or perception of risk; behavioral intentions; and behavioral response. Based on the 22 studies reviewed in this article, it was found that compared to a no-label control, nutrient warnings were visible, easy to understand, and improved consumers’ ability to identify unhealthy products. Other labeling systems were reported to provide more nutrition information and enabled participants to better rank products’ healthfulness. Overall, actual behavioral outcomes were tested less frequently than outcomes such as attention, comprehension, and purchasing intentions. Of the studies that tested behavioral outcomes, nutrient warnings improved the healthfulness of food purchases. More research is required to better understand the pathway to behavioral outcomes, particularly in reducing purchases of unhealthy food and beverages.
The paper examined 31 existing front-of-pack nutrient labelling regulations along three domains, 1) the form of regulation used (regulatory form), 2) its substantive terms and conditions (regulatory substance), and 3) the application of good governance in its development, administration, and enforcement (regulatory governance), in order to identify best practices for designing successful front-of-pack labelling regulations. Best practices identified in each domain include: Regulatory form: When designing regulations, governments should consider mandatory legal frameworks to overcome suboptimal voluntary uptake. For front-of-pack labels to promote healthier diets, policymakers should select a label that consumers can easily understand and use. Regulatory substance: The terms and content of the regulation should include strategic and measurable objectives, require specifications to ensure the label is clearly visible on the package, include nutrients and/or food components that address the relevant diet-related risks, specify a valid set of nutrient profiling criteria, apply broadly across most packaged foods in the market, and frame front-of-pack legislation within a comprehensive set of policies to promote healthier diets. Regulatory governance: Governments should initiate front-of-pack labeling and be responsible for setting regulatory objectives, scope, and criteria. Furthermore, government, or an independent body with the authority to monitor and enforce, should administer the regulation. A framework for monitoring and evaluation should be set during development and should include effective means of enforcement.
Several countries require labels on processed foods to indicate products high in salt. However, these labels are typically only applicable to multi-ingredient packaged foods, not to packages of salt where the only content is sodium chloride. This position statement requests governments to require health warnings on packages of salt sold for consumption and on salt dispensers in restaurants, such as saltshakers. The potential benefits of warning labels on packages of sodium chloride include increased awareness of the dangers of high sodium diets by those purchasing sodium and a reminder of the dangers by people seeing the containers at stores, food service establishments, or in the home. Additionally, stores that sell salt might display it less prominently, which could lead to a reduction in sodium consumption.
Knowledge and Behavior Change
Overall, 19 of the 22 studies looking at the effectiveness of population-level behavior change interventions on salt reduction reported significantly reduced estimated daily salt intake or improved self-reported salt-lowering behaviors. Of the 22 studies, 14 were health education interventions, 4 were public awareness campaigns, and 4 were multicomponent education interventions (both health education and awareness campaigns). “Of the 12 studies whose outcome was salt intake, 10 demonstrated significant reductions ranging from 0.9 g/d to 4.4 g/d.” The 3 studies showing no significant improvements were all health-education-only programs (as opposed to public awareness campaigns and multi-component interventions). Of the 10 studies classified as higher-quality studies (those with low risk of bias, e.g. selection bias, reporting bias), only 5 found significant effects on salt intake or behaviors based on the more objective outcome assessment method. Results of the study indicate that there is not yet a proven best method of reducing discretionary salt intake.
This review concluded that providing dietary advice to patients to reduce sodium intake had minimal impact, which emphasizes the need for population-wide changes in the options and default quantities of sodium in the commonly consumed foods. Results showed that individual interventions led to small reductions in blood pressure, but it is unclear whether the cost of implementing these interventions is justified. Interventions that do not rely on individual behavior change may prove to be more effective.
This document compiles lessons from four Latin American countries into a social marketing framework for salt reduction that ties together population-based and individual initiatives to create integrated and holistic salt reduction programs. It highlights a series of creative concepts and communication strategies that aim to decrease demand for salt and other high sodium products. The document identifies five international best practices from social marketing that may help achieve greater impact on current salt reduction efforts: 1) identify one segment of the ‘public’ whose behavior you hope to influence, 2) understand what drives people to consume high salt products, 3) isolate a single, immediate benefit that will make it worthwhile to give up salt and sodium products, 4) select one behavior to change at a time, facilitate that behavior and evaluate the outcome, and 5) choose surprising messages to change behavior.
Changing the Environment
Improving the “environmental context and conditions in which people live and make choices” is crucial in improving individual- and population-level dietary behaviors. Promising interventions and policies exist for improving behaviors in a variety of environmental contexts. For example, setting nutrition standards for foods available in schools, increasing availability of fresh fruit and vegetables in schools; establishing worksite programs to increase availability and decrease the price of healthy food; point-of-purchase promotion and targeted food placement in worksite cafeterias or supermarkets; preventing “food deserts” where healthy food is unavailable; smaller portion sizes; and nutrition information at restaurants. Disparities in access to and affordability of healthy food often negatively affect low-income and rural populations. Policies and programs should ensure that healthy options are available, identifiable, and affordable to people of all income levels and all geographic locations. Macro-level agricultural policies, government regulations that affect food pricing, and marketing restrictions should all be aligned with national nutrition goals to ensure healthy food is the default choice.
Restaurants
The systematic review provides the first global overview of salt reduction policies in restaurants. Of the 62 policies identified, menu labeling, target setting, and reformulation of recipes were the most common strategies used. Other strategies identified included consumer education, chef training, toolkit delivery, table salt removal, and media campaigns. Most policies focused on chain restaurants, and less than half (44%) were mandatory. There was limited evidence of the effectiveness of these strategies after implementation. Only 17 studies conducted an evaluation post-implementation, with 6 showing positive impacts, 8 little to no effect, and 3 simply described the overall salt reduction effect (not focused on restaurants). The positive impacts mainly came from menu labeling policies, which showed lower sodium content in meals, increased awareness of chefs and owners, and improved consumer choices. More research needs to be done to determine the feasibility and effectiveness of implementing sodium reduction policies in restaurants.
A literature review examining a total of 65 articles published from the year 2010 onwards found that among food vendors, perceived barriers to salt reduction included a lack of alternative recipe options, loss of sales, lack of technical skills for salt reduction in cooking, and an absence of environmental and systemic support for reducing the salt content. Consumers were generally unaware of their salt intake and of the negative health effects of high salt intake. Perceived barriers on the consumer side included the perception that low salt food had less flavor. Given that the barriers to sodium reduction outside the home are multifaceted for both the consumer and vendor, there is a need for multisectoral collaboration among policymakers, food industries, catering operators, and food vendors in population salt intake reduction. Potential enabling factors included structured intervention programs, easy access to salt substitutes, monitoring of salt intake, availability of education resources for vendors, and gradual rather than abrupt salt reductions.
The Healthy Chinese Take-Out initiative (HCTI) aimed to reduce the sodium content of dishes prepared by Chinese take-out restaurants in low-income urban communities in Philadelphia, USA through a chef training program. An evaluation in a subset of participating restaurants found a significant reduction in sodium in the three most popular dishes: reductions were 36% in shrimp and broccoli (from 5.5 to 3.5 mg/g), 28% reduction in chicken lo mein (from 5.7 to 4.1 mg/g), and 19% in General Tso’s chicken (from 5.9 to 4.8 mg/g). Chefs’ knowledge of the health consequences of sodium overconsumption increased significantly after the training and was maintained from through the final evaluation 36 months later. While chefs’ perceptions of the need to prepare low-sodium dishes and of their ability to do so increased significantly from baseline to post-training (P < .001), it returned to baseline levels by the final evaluation.
In 2015, the New York City Department of Health (DOH) implemented and enforced a regulation requiring warning labels on high sodium menu items (>2,300 mg/item) in chain restaurants. To create awareness for the regulation and foster restaurant compliance, the DOH held a press event with industry and mailed guidance to restaurants on how to meet the regulation requirements. They also rolled out a media campaign to educate the public about the warning icons in English and Spanish via print, television, and online media platforms. Days after the regulation went into effect, the National Restaurant Association filed a lawsuit to block its implementation. After an 18-month legal battle, the city won the lawsuit and enforcement began in 2016. The key steps for designing a high-sodium warning policy include designing the label, defining the sodium threshold above which consumers should be alerted, and determining which restaurants would be required to comply.
In 2015, the Korean Ministry of Food and Drug Safety launched a sodium reduction project in restaurants to reduce the daily sodium intake by 3,500 mg by 2020. Restaurants were designated as sodium reduction restaurants if 20% of the restaurant’s menu items reduced their sodium content (per serving) by 10% to less than 1300 mg or by more than 30% for menu items with more than 2,000 mg per serving. The study compares the sodium content of the restaurants that implemented the sodium changes to their menus before and after the project and evaluated the restaurants’ sodium reduction practices. On average, post intervention, the sodium content per serving decreased significantly from 1470 mg to 980 mg. The food groups with the highest sodium reduction rate were broth (46%), stir-fried dishes (39.5%), soups (35.8%), grilled dishes (34.8%), porridge dishes (33.5%), cooked rice dishes (31.8%) and steamed dishes (31.5%). Post intervention surveys showed that 70.6% of customers were ‘satisfied’ or ‘very satisfied’ with the sodium reduced menu. The findings from the study suggest that it is feasible to reduce the sodium content in restaurant food.
Four different online experiments were performed to determine the influence of different designs of sodium warning labels on the customers’ hypothetical meal choices, perceptions, and sodium knowledge. In experiments 1-3, all warning labels consistently reduced the average sodium ordered (by 19−81 mg) versus the control, the largest being traffic light and red stop sign labels (by 68 mg and 46 mg, respectively), but these results were not statistically significant. The 4th experiment tested the top performers from experiments 1-3 (traffic light and red stop sign warnings) against a control and found statistically significant reductions in average sodium ordered (-68 mg or -4.5% for traffic lights and -46 mg or -3.0% for red stop signs) as well as a reduction in the percentage of participants choosing a high-sodium items. Overall, participants who saw any type of warning label perceived high sodium meals to be saltier and reported a stronger belief that eating high sodium meals would increase their risk for high blood pressure (all p <0.001). Although these effects may appear relatively small, they may be meaningful at the population level.
Healthy Public Food Procurement
Healthy public food procurement and service policies set criteria for the service and sale of food in public settings or for government expenditures on food in order to increase the availability of foods that promote healthy diets and limit food that contributes to an unhealthy diet. The action framework serves as a tool for governments to develop, implement, monitor, and evaluate public food procurement and serve policies that align with the core principles of a healthy diet, which include 1) limiting sodium consumption and ensuring that salt is iodized; 2) limiting sugar intake; 3) shifting consumption of fat from saturated to unsaturated; 4) eliminating trans fat; 5) increasing consumption of whole grains, vegetables, fruit, nuts, and pulses; and 6) ensuring availability of free and safe drinking water. The action framework proposes 4 key policy steps for developing a public food procurement and service policy: 1) policy preparation outlines the key steps to take when developing or revising a healthy public food procurement and service policy; 2) policy development describes the steps of the policy development process which includes defining the purpose, scope, and nutrition; 3) policy implementation reviews the key steps to support and ensure full policy implementation; and 4) monitoring, enforcement, and evaluation guides the process of monitoring and enforcing the policy, as well as conducting a policy evaluation to determine whether the policy is effectively implemented.
“Healthy food procurement programs found in this review were nearly always effective at increasing availability of healthier food and decreasing that of less healthy food; contributing to the increased purchases of healthier foods and lower purchases of food high in fat, sodium and sugar.” A systematic review evaluated the impact of such policies on healthy eating and health outcomes and included procurement policies implemented in schools (19 studies), worksites (6 studies), remote communities (3 studies), and 6 studies in other settings including hospitals, care homes, correctional facilities, government institutions. No policy intervention identified was unsuccessful. Two studies which included health outcomes found improvement in blood pressure and BMI. Many procurement policies were strengthened by allied interventions such as educational programs or subsidies for healthy foods. Additionally, procurement policies may lead to reformulation of products to be healthier, although more research is needed in this area.
Added November 2022: Rosewarne E, Santos JA, Hart AC, et al. Review of national nutrition standards with salt-related criteria for publicly funded institutions around the world. Nutr Rev. 2022 Oct 7:nuac080.
This review conducted in 2019 identified 66 countries with national nutrition standards that included salt-related criteria for at least one publicly funded institution, a 78% increase since a 2014 review. Nutrition standards were most common in the European Region (62% of identified standards) and least common in the African Region (6%) and the South-East Asia Region (2%). No low-income countries were found to have existing standards. All identified countries had standards for school settings; less than half (42%) had nutrition standards for institutions other than schools (workplaces, hospitals, early-years settings, other educational settings, or sport and recreation centers). Most countries (79%) only included standards for one setting. More than half (58%) of the standards were mandatory, although few standards in workplaces or hospitals were mandatory. Most standards combined both food- and nutrient-based criteria (66%), and most were set as an “eligible/ineligible” approach, to indicate what foods/nutrients are permitted. Nutrition standards in public institutions have the potential to improve diets and reduce the NCD burden attributable to unhealthy diets. While progress has been made, it is recommended that more countries, particularly in low-income settings, develop effective policies following the WHO Action Framework for developing and implementing public food procurement and service policies for a healthy diet.
Low Sodium Salt Substitutes
Added November 2022: Ajenikoko A, Ide N, Shivashankar R, et al. Core Strategies to Increase the Uptake and Use of Potassium-Enriched Low-Sodium Salt. Nutrients. 2021. 13(9):3203.
This paper identifies four core strategies to increase uptake potassium-enriched low-sodium salt to reduce blood pressure and cardiovascular mortality: increasing availability, awareness and promotion, affordability, and advocacy. Strategies to increase the availability of low sodium salt include addressing the lack of availability in the global market as well as production and regulatory challenges. Working to resolve distribution and supply chain issues is also a method to allow for increased availability of low sodium salts. Strategies for awareness building and promotion were outlined as increasing awareness among consumers as well as healthcare providers to increase the demand of low-sodium salts. Increasing affordability means reducing currently much higher price of low-sodium salts to prices comparable to regular salt, through subsidies or vouchers. Advocacy efforts through addressing population concerns about possible hyperkalemia as well as engaging policy stakeholders to increase political will for uptake of these interventions.
Added November 2022: Yin X, Liu H, Webster J, et al. Availability, Formulation, Labeling, and Price of Low-sodium Salt Worldwide: Environmental Scan. JMIR Public Health Surveillance. 2021. 7(7):e27423.
This study identified 87 low-sodium salts in 47 of 195 countries worldwide, primarily in high- or upper-middle income countries (87%). Low sodium salts were between 1.1 and 15 times more expensive than regular salt. Sodium chloride content ranged from 0% (sodium-free) to 88%, with 59% containing potassium chloride, ranging from 0% to 100% in content. 49% percent of the salts carried labels outlining associated health risks, while 38% carried labels outlining associated benefits. Reported possible reasons for poor uptake of low sodium salts are a lack of widespread availability, high costs, and a lack of understanding of the benefits and possible risks of low-sodium salt intake. Policies to increase availability of, promote, standardize, and subsidize low sodium salts may contribute to reducing blood pressure and prevent cardiovascular disease.
Added November 2022: Yin X, Rodgers A, Perkovic, et al. Effects of salt substitutes on clinical outcomes: systematic review and meta-analysis. Heart Published Online First: 09 August 2022.
Meta-analysis of 21 trials among 31,949 participants across 4 geographical regions found that salt substitutes contribute to an overall reduction of systolic blood pressure (SBP) by -4.61 mm Hg and diastolic blood pressure (DBP) by -1.61 mm Hg, and every 10% reduction in the proportion of sodium chloride in the salt substitute was associated with a −1.53 mm Hg greater reduction in SBP and −0.95 mm Hg in DBP. Salt substitutes decreased risks of total mortality (pooled RR=0.89), cardiovascular mortality (pooled RR= 0.87), and major adverse cardiovascular events (pooled RR=0.89). Trials reporting urinary analysis showed salt substitute reduced urinary sodium excretion by −0.48 g/day and increased urinary potassium excretion by 0.45 g/day. Two studies reported no difference in hyperkalemia events between randomized groups, two others reported no effect of salt substitute on serum potassium levels, and six reported no serious adverse events attributable to hyperkalemia. This study demonstrates the potential of salt substitutes to reduce blood pressure globally, with consistent findings across diverse regions and populations.
The use of potassium-enriched salt substitutes as a public health strategy to lower sodium consumption could help reduce sodium intake and increase potassium intake at the population level. Evidence shows that replacement of sodium chloride with potassium-enriched salt substitutes lowers both systolic and diastolic blood pressure, by -5.58 and -2.88, respectfully, with greater blood pressure reductions in patients with high blood pressure. The main risk for widespread use of potassium-enriched salt substitutes is the potential for hyperkalemia in people with impaired kidney function or who are taking medications that impair potassium excretion. However, evidence linking potassium-enriched salt substitutes to the occurrence of hyperkalemia is limited to a few case reports; trials of salt substitutes of have reported some adverse events but have mostly excluded at risk individuals. More research on the population-wide impact of replacing sodium chloride with potassium-enriched salt substitutes is needed.
4.6.1 Country Examples
Added November 2022: Neal B, Wu Y, Feng X, et al. Effect of Salt Substitution on Cardiovascular Events and Death. New England Journal of Medicine. 2021. 385(12):1067-1077.
The SSaSS trial randomized 20,995 persons from 600 rural Chinese villages to either regular salt or a low-sodium substitute (25% potassium, 75% sodium). After an average of 4.74 years, participants in the low sodium group had a lower incidence of stroke (14%; 95% CI: 4 – 23%), major cardiovascular events (13%; 95% CI: 6 – 20%) and death (12%; 95% CI: 5-18%). The study also found that the rate of adverse events related to hyperkalemia was not significantly higher among those using the salt alternative compared to those using regular salt (3.35 and 3.30 events per 1000 person years). These findings demonstrate the clear effectiveness and minimal risk of increasing population uptake of low sodium salt in at risk groups to significantly reduce the burden of cardiovascular diseases. Findings are not necessarily generalizable to the entire population as participants either had a history of stroke or were above 60 with hypertension.
This stepped-wedge cluster trial in Peru found that individuals in households randomized to receive a salt substitute (75% NaCl and 25% KCl) had an average reduction of 1.29 mmHg in systolic blood pressure and 0.76 mmHg in diastolic blood pressure compared with controls. Among participants who were hypertensive at baseline, there was an average reduction in systolic blood pressure of 1.92 mmHg and 1.18 mmHg in diastolic blood pressure. Further, participants were 51% less likely to develop hypertension in the intervention period than in the control period. Urinary analysis showed an increase in mean potassium intake (mean difference of 0.63 g) but no change in sodium intake. While the reductions in blood pressure are modest, they carry large public health gains. To increase uptake of the salt substitute, investigators developed a brand identity (named by the local community) and a social marketing campaign, which was conducted before and during the intervention.
A cluster-randomized trial in 120 villages in rural northern China measured the effects of providing access to a low-sodium, potassium-based salt substitute along with health education on sodium reduction. Of the 60 villages receiving the intervention, half also received a price subsidy for the low-sodium salt. At the end of the trial, “mean urinary sodium excretion in intervention compared with control villages was 5.5% lower (-14mmol/day, 95% confidence interval -26 to -1; p = 0.03), potassium excretion was 16% higher (+7mmol/day, +4 to +10; p<0.001), and sodium to potassium ratio 15% lower (-0.9, -1.2 to -0.5; p<0.001).” Use of low-sodium salts was twice as high among intervention sites receiving the price subsidy than intervention sites not receiving the subsidy; the estimated effect on urinary sodium was not statistically significant, possibly due to lower sample size. Knowledge relating to salt and salt substitute improved in the intervention group.
For similar articles, see:
Yu J, Thout SR, Li Q, et al. Effects of a reduced-sodium added-potassium salt substitute on blood pressure in rural Indian hypertensive patients: a randomized, double-blind, controlled trial. AJCN. 2021. 114(1):185-193.
This 5-year cluster RCT (see Neal 2021) found that replacing regular salt with low sodium salt reduced risk of stroke by 14%, and increased quality-adjusted life years (QALYs) per person by about 0.054 years (about 20 more days in full health per person. Cost-effectiveness of the salt substitute intervention was calculated, taking into account healthcare costs (inpatient and outpatient) and intervention costs. The average costs for the intervention group were lower than the control group (USD 230.92 vs. USD 247.59). The salt substitute intervention had a 95.0% probability of being cost-saving in regard to QALYs and a greater than 99.9% probability of being cost-effective.
This modelling study shows that replacing discretionary salt with a potassium-enriched salt substitute could potentially save 450,000 lives from cardiovascular disease in China annually. The study used comparative risk assessment models to estimate the benefits, harms, and net effects of a nationwide intervention to replace discretionary dietary salt (NaCl) with potassium enriched salt substitutes (20-30% potassium chloride), projecting the prevention of 461,000 deaths due to cardiovascular disease, 208,000 due to stroke and 175,000 due to ischemic heart disease, as well as 740,000 non-fatal cardiovascular events annually. The intervention also estimated 21,000 fewer deaths in individuals with chronic kidney disease. The study noted that due to the risks associated with increased potassium, the intervention could potentially produce an estimated 11,000 additional deaths related to hyperkalemia in individuals with chronic kidney disease. Overall, the study suggests that potassium-enriched salt substitutes can have a large effect on the burden of cardiovascular disease in China and potentially other countries with a high discretionary salt intake.
For similar articles, see:
Marklund M, Tullu F, Raj Thout S, et al. Estimated Benefits and Risks of Using a Reduced-Sodium, Potassium-Enriched Salt Substitute in India: A Modeling Study. Hypertension. 2022 Oct:10-161.
This modeling study found that when “feasible and practical” levels of sodium (14-35% depending on the category) were replaced with potassium in 18 major US food categories, sodium intake would decrease by 9% and potassium intake increase by 15%. Using NHANES data, results show that this replacement (294 mg/d of sodium is removed and replaced with 390 mg potassium) could decrease average sodium intake from 3410 to under 3000mg/d, which is the US FDA short-term intake goal. The replacement would also increase potassium intakes to recommended levels and lower the intake ratio of sodium to potassium, which may support blood pressure control. The replacement of NaCl with KCl in select foods therefore provides a viable strategy to help lower the US population’s intake of sodium and improve health outcomes.
Fiscal Policies
Added November 2022: Colchero MA, Paraje G, Popkin BM. The impacts on food purchases and tax revenues of a tax based on Chile’s nutrient profiling model. PLoS One. 2021. 16(12):e0260693.
This modeling study determined that imposing a tax on food products bearing a warning label under Chile’s 2016 Law of Food Labeling and Advertising could potentially generate between 457 million to 1.3 billion USD in revenue, depending on the tax rate (three scenarios were considered: 10%, 20%, 30%). Except for labeled fish and meat, all food and beverage groups were found to be price elastic. Researchers used household food and beverage purchases obtained from Kantar and sales data from the Euromonitor database across a panel of Chilean cities. This study demonstrates the potential of front-of-package warning label policies to also be used to guide additional public health policies that decrease the negative impact of diet-related non-communicable diseases.
Implementation Tools
World Cancer Research Fund International.Lessons on implementing a robust sugar sweetened beverage tax. 2018. (Focuses on sugar sweetened beverage taxes, although many lessons can be applied to potential salt or junk food/HFSS taxes)
Other Resources
Country Examples
In January 2014, the Mexican government implemented an 8% tax on nonessential foods with energy density > 275 kcal/100 g, including salty snacks and junk food, and a peso-per-liter tax on sugar-sweetened beverages (SSBs). The study examines changes in the volume of taxed and untaxed food purchases after both taxes were implemented. On average, the total volume of taxed purchases had an absolute decline of 25 g per capita per month (p < 0.05), or a -5.1% relative change beyond what would have been expected based on pre-tax trends. In 2014, low SES households purchased on average 10.2% less taxed foods than expected (p < 0.05), whereas medium SES households purchased 5.8% less taxed foods (p < 0.05), and high-income households’ purchases did not change. The greatest changes in total purchases were observed among taxed salty snacks (-6.3% below expected, p < 0.05) and taxed cereal-based sweets (-5.2% below expected, p < 0.05), while taxed non-cereal-based sweets and ready-to-eat cereals did not change.
In 2011, Hungary’s Public Health Product Tax (PHPT) was enforced, with the aim to reduce consumption of unhealthy food products, promote a healthy diet and make healthy food choices accessible, and to improve public funding for health care services, especially public health programs. An impact assessment of the tax suggests that consumers who purchased salty snacks and pre-packaged sweets changed their consumption, by 16% and 14% respectively, while 11% of people who ate powdered soup and salty condiments changed their consumption. Higher prices were cited as the reason for changing consumption of pre-packaged sweets and salty snacks by 81% of people who changed their consumption in 2012 and by 66% and 56%, respectively, in 2014. Those who reduced their consumption were two to three times more aware that the product was unhealthy.
This study used a cost-effectiveness model to evaluate a range of food and drink taxes and subsidies to determine an optimally cost-effective package of tax and subsidy options for the Australian population. The five intervention options modeled included: 1) taxing saturated fat, 2) taxing excess salt in processed food, 3) taxing sugar-sweetened beverages, 4) subsidizing fruits and vegetables, and 5) taxing processed foods high in sugar. Of the 5 taxes and subsidies, only the sugar tax led to the most improvements in dietary measures – a reduction in sodium and energy intake and an increase in fruit and vegetable intake. The excess salt tax had the next highest impact, leading to reductions in sodium intake (-67 mg/day) and energy intake (-161 kJ/day). Individually, the taxes examined all led to an improvement in population health, ranging from 12,000 – 270,000 DALYs averted in the Australian population. The combination of all five tax and subsidy interventions led to 470,000 DALYs averted and a net cost saving of AU$3.4 billion, with a 100% probability of cost-savings.
Marketing Restrictions (Added November 2022)
This descriptive review on the extent and nature of food marketing concludes that food marketing continues to be prevalent everywhere and predominantly promotes foods that contribute to unhealthy diets, affecting adults as well as children. Evidence suggests that unhealthy food marketing is prevalent in settings where children gather (e.g., schools, sports clubs) as well as on TV, which has traditionally been the dominant medium for food marketing particularly during children’s typical viewing times and programming. Strategies used to appeal to children include celebrity/sports endorsements; characters; promotions, gifts/incentives and tie-ins; competitions; games; color, visual imagery and novel designs; animation and special effects; branding; persuasive appeals; health/nutrition claims and disclaimers (e.g., “healthy breakfast”); and others. These strategies were used more frequently to promote unhealthy foods compared with healthier products. Exposure to food marketing was positively associated with habitual consumption of advertised foods or less healthy foods. Feelings of happiness and satisfaction after exposure to ads and positive perceptions toward food advertising, were associated with increased consumption in children. Children reported seeing a high volume of food marketing and recognized brands and products. Deceptive practices such as the use of healthy foods imagery, health claims, or cross-branding with healthier products were found. Parents believed governments should do more to restrict children’s exposure to food marketing. The review also outlines future challenges to address with the rise of marketing via online/digital and social media and reaffirms the case for restrictions on food marketing for children on these platforms, which have grown widely in use among children.
Added November 2022: World Cancer Research Fund International. Building Momentum: lessons on implementing robust restrictions of food and non-alcoholic beverage marketing to children. 2020.
This report provides guidance for policymakers to design and implement government-led, mandatory food marketing restrictions. International and legal policy frameworks can be used as tools to drive government action and guidance is provided on creating clear policy objectives about what marketing restrictions will achieve and how they will operate. Specific evidence to consider including in policy design are listed: burden of NCDs; diet and health behavior; existing nutrition guidelines; marketing exposure and power; current marketing/advertising regulations and international social media protections for children; costs and benefits. Key decisions presented include deciding what legal measures to use, who should be protected, which forms of marketing should be restricted, and which foods and beverages should be restricted. Strategies for stakeholder engagement, monitoring and evaluation, defending policy, lessons learned, and case studies from various countries are also included.
Added November 2022: Taillie LS, Busey E, Stoltze FM, et al. Governmental policies to reduce unhealthy food marketing to children. Nutr Rev. 2019. 77(11):787-816.
This narrative review provides information on existing governmental regulations that restrict unhealthy food marketing and reviews evidence on the effects of these regulations. Only 10 countries restrict marketing of unhealthy food to children. Television was the most frequently restricted medium while other forms of media (cinema, mobile, print, packaging, and the internet) were not commonly regulated. Types of foods and beverages covered under policies and the nutritional criteria used to identify them varied. Free gifts and toys and the use of celebrities or characters were restricted most frequently. Restrictions on promotions and health/nutrition claims were less common. Evaluation studies (available for only four countries) found modest differences in the amount of unhealthy food advertising on TV before and after regulations, or between jurisdictions with and without regulations, possibly because the restrictions applied only to children’s programming during narrow windows of time. More research is needed to identify policy components most critical for a regulation to effectively reduce children’s exposure to unhealthy food marketing, improve children’s diet, and prevent obesity.
One year after a 2016 regulation in Chile restricted child-directed marketing of products high in energy, saturated fats, sodium, and sugars, children’s exposure to advertising of unhealthy foods on popular broadcast and cable television decreased significantly (but was not eliminated). Exposure to ads for unhealthy foods with child-directed appeals (such as cartoon characters) decreased by 35% and 52% for preschoolers and adolescents, respectively, with larger decreases for children who viewed more television. Subsequent stages of the labeling law were anticipated to strengthen the effects of the marketing restrictions, such as by removing all programming of restricted products between 6am and 10pm as well as capturing more restricted products as the nutrient thresholds are raised.
