Sodium Reduction: An annotated bibliography

Webster J, Waqanivalu T, Arcand J, et al. Understanding the science that supports population-wide salt reduction programs. J Clin Hypertens. 2017;19(6):569-576. doi:10.1111/jch.12994. 2017;19(6):569-576.

Despite some limitations in available data, expert scientific groups overseen by governmental or nongovernmental health and scientific organizations agree on the need to reduce population salt intake. Salt reduction could result in millions of lives saved annually, especially cardiovascular deaths caused by hypertension. Although few randomized controlled trials (RCT) have been conducted to directly examine the effects of salt reduction on cardiovascular disease (CVD) due to feasibility and ethical concerns, pooling CVD data from RCTs with long-term follow up “have demonstrated a reduction in cardiovascular events with reduced dietary sodium.” A limited number of studies have concluded that low levels of sodium intake are associated with increased mortality; however, the methodologies of these studies are flawed. Strong evidence from higher-quality studies shows that CVD is reduced with lower intakes of dietary sodium. “The recent publication of a few paradoxical studies of questionable scientific merit should not delay implementation of salt reduction initiatives worldwide.”

He FJ, Campbell NR, Ma Y, et al. Errors in estimating usual sodium intake by the Kawasaki formula alter its relationship with mortality: implications for public health. IJE. 2018 Jun 22.

Use of the Kawasaki formula to estimate usual sodium intake can artificially introduce a J-shape curve. Sodium intake from 2,974 pre-hypertensive participants of the Trials of Hypertension Prevention (TOHP) study was assessed using four methods and compared to mortality. When using the gold standard method to measure sodium intake (multiple seven 24-h urinary sodium measurements), a linear relationship with mortality was found. Estimating usual intake by applying the Kawasaki formula (frequently applied to spot urines to estimate usual intake) to the sodium concentration from 3-7 collections, sodium at lower levels was over-estimated and sodium at higher levels was under-estimated. Further, using this method rather than the gold standard method, investigators observed an artifactual J-shaped relationship between sodium intake and mortality.

Olde Engberink RHG, van den Hoek TC, van Noordenne ND, et al. Use of a Single Baseline Versus Multiyear 24-Hour Urine Collection for Estimation of Long-Term Sodium Intake and Associated Cardiovascular and Renal Risk. Circulation. 2017;136(10):917-926.

Using a single baseline 24-hour urine measurement rather than multiple measurements to estimate usual sodium intake can introduce an artifactual J-shaped relationship between sodium intake and CVD. Single baseline 24-hour sodium measurements as well as (multiple) follow-up 24-hour urine samples provide similar estimates of sodium intake on a population level; however, when used to estimate individual sodium intake, the two methods differ. When using a single baseline measurement, there was no significant association between high sodium intake and increased cardiovascular events/mortality and the curve appeared j-shaped. When using average measurements over 1 to 5 years, there was a significant, linear association.

Karppanen H, Mervaala E. Sodium intake and hypertension. Progress in Cardiovascular Diseases. 2006 Sep 1;49(2):59-75.

This article summarizes the scientific evidence relating high population salt intake with high prevalence of hypertension, using Finland as a case study. As average salt intake decreased by one third over 25-30 years in Finland, there was a simultaneous decrease of more than 10mm Hg in average population blood pressure (systolic and diastolic), a 75% to 80% decrease in both stroke and coronary heart disease mortality among those less than 65, and a 5- to 6-year increase in life expectancy. The article also describes salt-labeling legislation, such as the “high salt content” warning labels. This legislation encouraged product reformulation, resulting in reduced average salt content in the most important food categories. A sodium-reduced, potassium-, and magnesium-enriched salt alternative was also available and promoted. Methods for successful population level salt reduction are summarized.

He FJ, Pombo-Rodrigues S, Macgregor GA. Salt reduction in England from 2003 to 2011: its relationship to blood pressure, stroke and ischaemic heart disease mortality. BMJ Open. 2014;4(4):e004549. Published 2014 Apr 14.

A nationwide salt reduction program was introduced in the UK in 2003, and by 2011, a 15% reduction in population salt intake was observed. During this same period, a significant decrease in BP of 2.7 /1.1 mm Hg (p<0.001 for systolic and diastolic BP) was observed after adjusting for major factors known to be associated with BP. Decreased BP appears to be at least partially attributable to population salt reduction.

Mueller NT, Noya-Alarcon O, Contreras M, Appel LJ, Dominguez-Bello MG. Association of Age With Blood Pressure Across the Lifespan in Isolated Yanomami and Yekwana Villages. JAMA Cardiol. 2018;3(12):1247-1249.

This study among the Venezuelan Yanomami community (hunter-gatherer-gardeners with very low salt exposure) and the nearby Yekwana community (who have intermittent exposure to processed foods and salt) found that only the Yekwana experience an age-related rise in blood pressure. While both communities start out with similar blood pressures in early childhood, between-group differences in blood pressure increase with age rising to a 15.9 mm Hg difference by age 50 (the age-SBP slope was significantly steeper for Yekwana individuals). Overall, the Yanomami had significantly lower systolic and diastolic blood pressure than the Yekwana (SBP: 95.4 mmHg vs. 104.0 mmHg, P<0.001; DBP: 62.9 mm Hg vs. 66.1 mmHg; P = 0.03).

Zhang J, Guo X, Lu Z, et al. Cardiovascular Diseases Deaths Attributable to High Sodium Intake in Shandong Province, China. JAHA. 2019 Jan 8;8(1):e010737.

Using 24-hour urinary sodium data from the 2011 SMASH study, authors estimated the annual number of CVD-related deaths in Shandong province attributable to high sodium intake and modelled the number of lives potentially saved through a 30% reduction in sodium intake. High sodium intake (>2000mg/day) was estimated to account for an estimated 16,000 CVD-related deaths in 2011 among those aged 25-69 (or nearly 20% of total CVD deaths) in Shandong. With a 30% reduction in sodium intake, Shandong province could potentially avert 8,800 sodium attributed CVD deaths, and with the SMASH sodium reduction goal of 4g/day, 6,700 sodium attributed deaths could be averted.

Watkins DA, Olson ZD, Verguet S, et al. Cardiovascular disease and impoverishment averted due to a salt reduction policy in South Africa: an extended cost-effectiveness analysis. Health Policy and Planning. 2015 Apr 3;31(1):75-82.

Authors conducted a cost-effectiveness analysis to assess the South African Government policy to lower population salt intake to 5g per person/day by regulating salt in processed foods and conducting media campaigns. The policy would avert approximately 5,600 deaths and 23,000 cases of CVD yearly (11% of CVD deaths). It would also save US$ 4.06 million in household out-of-pocket expenditures on CVD, save US$51.25 million in government healthcare subsidies, reduce catastrophic spending, and prevent nearly 2,000 cases of poverty annually. Reformulating food products could cause food prices to rise, but the increase would at worst only be slightly more than the out of pocket expenditures averted.

Mason H, Shoaibi A, Ghandour R, et al. A cost effectiveness analysis of salt reduction policies to reduce coronary heart disease in four Eastern Mediterranean countries. PloS One. 2014 Jan 7;9(1):e84445.

A study of the cost-effectiveness of three salt reduction policies (health promotion campaign, labelling, and mandatory reformulation of salt content in processed food) in Tunisia, Syria, Palestine, and Turkey found that compared to no policy, the number of life years gained increased in all countries with all policies (separately and in combination). The majority of policies were cost saving as well. Combining all 3 interventions resulted in the highest estimated cost savings, ranging from $6 million in Palestine to $1.3 billion in Turkey. Life years gained (LYG) under the same scenario included 6,455 LYG in Tunisia; 31,674 LYG in Syria; 2,682 LYG in Palestine and 378,439 LYG in Turkey.

Dehmer SP, Cogswell ME, Ritchey MD, et al. Health and Budgetary Impact of Achieving 10-Year U.S. Sodium Reduction Targets. Am J Prev Med. 2020;59(2):211-218.

This study uses microsimulation modeling to estimate the potential health effects and associated budgetary impacts of averted disease costs over a 10-year period if mean sodium consumption among US adults is reduced to 2,300 mg/day. A 10-year graduated reduction in dietary sodium is projected to reduce the number of Americans with SBP > 140 mmHg by 6.9 million (22% reduction) and the number of Americans with SBP between 120 – 139 mmHg by 8.1 million (13% reduction). The reductions in sodium consumption are estimated to prevent 895,200 CVD events and 252,500 CVD-related deaths. The potential health benefits correspond with an estimated reduction in medical costs from averted disease by $36.9 billion across all payers in 10 years and increased productivity from reduced disease burden and premature mortality would account for an additional $18 billion in gains.

Spot urine samples are much easier to collect and require far fewer resources than the gold standard, 24-hour urine method. This section looks at evidence examining how spot urine samples perform compared to 24-hour urine in determining population sodium intake.

Campbell NRC, He FJ, Tan M, et al. The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) position statement on the use of 24-hour, spot, and short duration (24 hours) timed urine collections to assess dietary sodium intake. J Clin Hypertens. 2019;21(6):700-709.

Based on a review of multiple systematic reviews and analyses, the International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) concludes that the recommended method for assessing population dietary sodium intake is to collect “single complete 24-hour urine samples, collected over a series of days from a representative population sample” and for individual level estimations, “at least 3 non-consecutive complete 24-hour urine collections collected over a series of days that reflect the usual short-term variations in dietary pattern.” Generally, spot urine samples systematically underestimate changes in dietary sodium intake at the population level. To understand the role of single spot or short duration timed urine collections in assessing population average sodium intake will require more research. Single spot or short duration timed urine collections are not recommended for individual sodium intake estimation.

Brown IJ, Dyer AR, Chan Q, et al. Estimating 24-hour urinary sodium excretion from casual urinary sodium concentrations in Western populations: the INTERSALT study. Am J Epidemiol. 2013;177(11):1180-1192.

Spot urine concentrations and 24-hour urinary sodium excretion collected by the Intersalt study (1885-1987 in 32 North American and European countries) were compared to determine the utility of estimating 24-hour urinary sodium excretion using spot urine specimens. The correlation (Pearson r) between observed and estimated 24-hour sodium excretion was 0.50 for individual men and 0.51 for individual women, and .79 for men at the population-level and 0.71 for women at the population-level. Bias was minimal (-1.8 mmol men; 2.2 mmol women) at the population level. Using spot urine estimations, the percent of people with sodium intake above the recommended levels was slightly higher than with observed 24-hour sodium excretion. Spot urine specimens may be able to provide useful estimates of population but not individual sodium intake.

Huang L, Crino M, Wu JH, et al. Mean population salt intake estimated from 24-h urine samples and spot urine samples: a systematic review and meta-analysis. Int J Epidemiol. 2016;45(1):239-250.

This study (a review of 29 studies estimating daily salt intake based on both spot and 24-hour urine) provides evidence that spot urine samples can be used to provide estimates of mean population salt intake; however, because spot urine systematically overestimated lower levels of salt intake and underestimated higher levels compared to 24-hour urine, spot urine samples should not be used to detect changes in average population salt consumption over time. For estimating mean population salt intake as above or below a 5g/day threshold, spot urine had a sensitivity of 97% and specificity of 100% (assuming 24-hour urine to be gold standard).

Tan M, Wang C, Song J, He FJ, MacGregor GA. Spot urinary sodium to monitor relative changes in population salt intake during the UK salt reduction programme. J Hypertens. 2022;40(7):1406-1410.

The gold standard method to measure population salt intake is complete 24-hour urine measurements, and previous studies have demonstrated challenges with using spot urine samples to estimate overall sodium intake. This study, however, found that measurement of change in mean population sodium intake over time can be conducted using the sodium concentration of spot urine samples. This was true in both random and representative population samples taken to monitor population salt reduction programs. Data was pulled from intermittent 24-hour urine samples (n=2020) and spot urine samples (n=21711) collected in 4 separate cross-sectional surveys between the years 2005 and 2014 conducted among a representative and randomly selected sample of the UK population. The study found that the relative changes collected in spot urine and 24-hour urine samples were similar across the various time intervals between the surveys, providing evidence towards a more cost-effective monitoring method for sodium reduction interventions. However, spot urine samples should not be used to measure individual sodium intake. Further, the study found that the Kawasaki, Tanaka, and INTERSALT formulas are not suitable to estimate 24-hour urine or monitor changes in population salt intake, as they systematically underestimate higher salt intakes and overestimate lower salt intake.

McLean RM, Farmer VL, Nettleton A, et al. Twenty-Four-Hour Diet recall and Diet records compared with 24-hour urinary excretion to predict an individual’s sodium consumption: A Systematic Review. J Clin Hypertens. 2018;20(10):1360-1376.

Thirty studies assessing individual sodium consumption compare estimates from 24-hour dietary recall or diet records vs. gold standard 24-urine collections. Results showed a wide variation between the methods. Correlations coefficients comparing diet recall to 24-hour urine ranged from 0.16 to 0.72. Comparing food diaries to the gold standard, correlations ranged from 0.11 to 0.49. The two studies that reported results of Bland-Altman limits of agreement analyses both found 24-hour diet recall did not accurately estimate intakes from 24-hour urines. Diet records or dietary recall alone may be useful to determine intake of certain nutrients, food groups, or dietary patterns, but is prone to error when used to determine individual sodium consumption or the relationships between individual sodium intake and health outcomes. Studies that rely solely on dietary assessment as a measure of individual sodium intake “must be viewed carefully and skeptically”.

Elorriaga N, Gutierrez L, Romero IB, et al. Collecting Evidence to Inform Salt Reduction Policies in Argentina: Identifying Sources of Sodium Intake in Adults from a Population-Based Sample. Nutrients. 2017 Aug 31;9(9):964.

Prior to implementing new legislation limiting the sodium content in select processed foods in Argentina, a 34-item Food Frequency Questionnaire was administered to 2,217 adults to estimate sodium intake from select foods, use of available low-salt alternatives, and the frequency of discretionary salt use. Average salt intake from selected processed foods was 4.7g/day (higher among men and those with lower education). “Soups and other convenience foods” were found to be the highest source of sodium (36.1%), followed by “Bread, crackers and cookies” (24.9%), “Meat products” (18.7%), and “Cheeses” (15.0%). Categories of foods with regulated maximum limits accounted for 47.6% of the total sodium intake from processed foods. Discretionary salt use was high, with 83.2% reporting always or often using use salt at the table or during cooking.

Roselló-Araya M, Madriz-Morales K, Vega-Solano J, et al. Estimation of Sodium Availability and Food Sources from 2018 to 2019 and Its Trends during the 2004-2019 Period in Costa Rica. Nutrients. 2022;14(15):3200.

A survey conducted in 2018–2019, based on food and beverage purchase records from the Costa Rica Household Income and Expenditure Survey, found that sodium available for consumption (sodium available on the market) slightly decreased (by 0.52%) since the previous survey in 2013–2014, after increasing 12% from 3.40 to 3.86 g/person/day from 2004–2005 to 2013–2014. Table salt was the main source of dietary sodium (60.2%) in 2018-2019, with participants using an estimated 2.5 g/day. Processed and ultra-processed foods with added sodium were the second largest source of sodium (0.65g/day), followed by condiments with added sodium, natural and processed foods without added sodium, and prepared dishes.

Johnson C, Santos JA, Sparks E, et al. Sources of Dietary Salt in North and South India Estimated from 24 Hour Dietary Recall. Nutrients. 2019;11(2):318. Published 2019 Feb 1.

In both North and South India, added (discretionary) salt was the main source of sodium in the diet (87.71% in South India and 83.45% in North India). Additional sources in the south included meat, poultry, and eggs (6.3%), dairy and dairy products (2.6%), and fish and seafood (1.6%); in the north, additional sources included dairy and dairy products (6.4%), bread and bakery products (3.3%), and fruits and vegetables (2.1%). No significant differences were found within regions for salt intake based on sex, age, or education level. In South India, urban areas consumed more salt from added salt than rural areas (90% vs. 86%); however, in North India, rural areas consumed more (86% vs. 81%). Data was collected based on two 24-hour dietary recalls from 1,283 participants selected from rural, urban, and slum areas in North and South India.

Du S, Wang H, Zhang B, Popkin BM. Dietary Potassium Intake Remains Low and Sodium Intake Remains High, and Most Sodium is Derived from Home Food Preparation for Chinese Adults, 1991-2015 Trends. J Nutr. 2020;150(5):1230-1239.

This study assessed changes in sodium intake over time from the China Health and Nutrition Survey, an open cohort study conducted between 1991-2015. Detailed diet data was collected for 29,926 Chinese adults, using weighing methods at the household level in combination with three consecutive 24-hr recalls at the individual level. Sodium intake was 6.3g/d in 1991, decreasing to 4.1 g/d in 2015. Sources of sodium intake did not change significantly over time. The major source of sodium was salt added during cooking, which accounted for 67% of the total sodium intake in 2015. Sodium from processed foods increased slightly, from 5.0% in 1991 to 8.8% in 2015. The sodium/potassium ratio decreased from 4.1 in 1991 to 3.1 in 2015, 5 times higher than the WHO recommendation. Overall, sodium intake in China remains very high and further sodium reduction efforts need to be considered

Song Y, Li Y, Guo C, et al. Cross-sectional comparisons of sodium content in processed meat and fish products among five countries: potential for feasible targets and reformulation. BMJ Open. 2021;11(10):e046412.

Findings from this cross-sectional study comparing sodium content in processed meat and fish products across the US, UK, China, South Africa, and Australia show a two to three-fold difference in sodium levels between the highest and lowest ranking countries.Based on data from 26,500 products collected between 2012-2018, China had the highest overall sodium levels (median 1050mg/100g), followed by the USA, South Africa, Australia, with the UK having the lowest (median 432mg/100g). These rankings differed when looking at specific subcategories such as meat products alone (Australia ranked lower than the UK) or cured meats (China ranked the lowest). When assessed using the UK ‘Traffic Light’ criteria, only a very small percentage (no country having more than 10%) of products fell into the “green light” group, and when assessed using the UK 2017 sodium targets, the number of meat and fish products meeting the targets ranged from 7.1% in China to 26.6% in UK. The selected countries had varying salt target policies in place, which may have impacted the wide differences in sodium content per category. This analysis makes a strong case for robust salt target policy development, implementation, and monitoring.

Webster J, Santos JA, Hogendorf M, et al. Implementing effective salt reduction programs and policies in low- and middle-income countries: learning from retrospective policy analysis in Argentina, Mongolia, South Africa and Vietnam. Public Health Nutr. 2022. 25(3):805-816.

This study assessed the influences on implementation of salt reduction policy in Argentina, Mongolia, South Africa, and Vietnam. Despite varying contexts in each country, important factors for scaling salt reduction programs across each country included: the collection of reliable local data on the main sources of salt, engaging multi-sector stakeholders both nationally and internationally in the implementation process, strong government leadership and willingness to regulate, and available resources for implementation and monitoring of both salt intake and salt levels in food. None of the included countries had a sufficiently comprehensive surveillance program and all relied on suboptimal methods to measure salt intake. Funding to implement and monitor sodium reduction policies and their progress was a major barrier cited by all countries.

Laatikainen T, Nissinen A, Kastarinen M, et al. Blood Pressure, Sodium Intake, and Hypertension Control: Lessons From the North Karelia Project. Glob Heart. 2016;11(2):191-199.

This article describes the North Karelia Project, an intensive hypertension prevention and control program started in 1972 in North Karelia, Finland. In the late 1970s, sodium reduction efforts were scaled up to address the extremely high intake of sodium in the population, which eventually resulted in decreased average salt intake as well as significant reductions in blood pressure between 1982 and 1997. Interventions included: 1) health education targeted to the whole population, 2) education of patients including nutrition counselling, 3) training of personnel on the association between salt intake and blood pressure and on food preparation, and 4) environmental changes including introduction of low-sodium salt, reducing salt content in school meals and at other institutions, and working with industry to reformulate products with less salt.

Xu A, Ma J, Guo X, et al. Association of a Province-Wide Intervention With Salt Intake and Hypertension in Shandong Province, China, 2011-2016. JAMA Intern Med. 2020;180(6):877-886.

The Shandong-Ministry of Health Action on Salt and Hypertension (SMASH) program was a government-led, population-based intervention to reduce salt intake and decrease the risk of hypertension among adults in Shandong province. The program consisted of a media campaign and distribution of scaled salt spoons, along with promotion of low-sodium products in markets and restaurants and public education activities targeting reduction of sodium at home and at school. The program led to a decrease in sodium intake in Shandong province of 24.8% from 2011 to 2016 (5,338 mg/day to 4,013 mg/day) as measured by 24-hour urine sodium excretion. In addition, potassium excretion increased by 15.1% (from 1,607 mg/day to 1,850 mg/day) and the sodium to potassium ratio decreased by 36.6% (6.9 to 4.3). The adjusted mean systolic BP decreased by 1.8 mm Hg from 131.8 in 2011 to 130 mm Hg in 2016 (p = 0.04). The adjusted mean diastolic BP decreased by 3.1 mm Hg from 83.9 mm Hg to 80.8 mm Hg (p < 0.001). Sodium reduction and hypertension knowledge, attitudes, and behaviors significantly improved, including knowledge of the salt intake recommendation by the Chinese Dietary Guidelines, attention paid to processed food labeling, and actions taken to reduce sodium in the diet. Findings of the study suggest that SMASH is the first large scale population-based intervention primarily relying on behavior change that showed such a large reduction in sodium intake, and therefore may have implications for sodium reduction and blood pressure control in other regions of China and worldwide.

Park HK, Lee Y, Kang BW, et al. Progress on sodium reduction in South Korea. BMJ Glob Health. 2020;5(5):e002028.

South Korea’s sodium reduction program led to a 23.7% reduction in adult dietary sodium intake between 2012 and 2014. The program included five components: (1) a consumer awareness campaign designed to change food consumption behaviors; (2) increased availability of low-sodium foods at school and worksite meal services; (3) increased availability of low sodium meals in restaurants; (4) voluntary reformulation of processed foods to lower the sodium content; and (5) development of low-sodium recipes for food prepared at home. The reductions in sodium were accompanied by reductions in population blood pressure and hypertension prevalence. The reductions in salt in kimchi, one of the major sources of sodium in South Korea, was a big driver for the change. The engagement of the food industry in product reformulation also helped with the reduction of sodium intake. Lessons learned from South Korea, particularly its multi-component approach and focus on major contributors to sodium intake, could be applied to other countries, particularly those with similar food sources and consumption profiles.

He FJ, Brinsden HC, MacGregor GA. Salt reduction in the United Kingdom: a successful experiment in public health. J Hum Hypertens. 2014;28(6):345-352.

“(T)he United Kingdom now has the lowest known salt intake of any developed country as measured by 24-h urinary sodium” (as of 2014). The nine key components of the salt reduction program in the United Kingdom, were: (1) setting up an action group; (2) determining salt intake and sources of salt; (3) setting a target for population salt intake and developing a salt reduction strategy; (4) setting progressively lower salt targets for industry with a clear time frame; (5) working with the industry to reformulate food with less salt; (6) engaging and recruiting of ministerial support; (7) clear nutritional labelling; (8) consumer awareness campaign; and (9) monitoring progress. The salt reduction program in the UK achieved a 15% reduction in average salt intake, from 9.5g/day in 2003 to 8.1g in 2011 (P<0.05). Product surveys show that the salt content in processed foods decreased during the program, including a 20% decrease in bread and 45% in ready meals. Between 2003-2007, the percentage of adults who add salt at the table decreased from 32.5% to 23.2%, and sales of table/cooking salt decreased by approximately 20%. The program was shown to be very cost-effective (£1.5 billion saved per year) and led to approximately 6,000 fewer deaths from cardiovascular disease per year by 2008.

Laverty AA, Kypridemos C, Seferidi P, et al. Quantifying the impact of the Public Health Responsibility Deal on salt intake, cardiovascular disease and gastric cancer burdens: interrupted time series and microsimulation study. J Epidemiol Community Health. 2019;73(9):881-887.

The Public Health Responsibility Deal was a public-private partnership launched in England, which gave greater freedom to the food industry to set and monitor targets for salt content of food, eliminating the Food Standards Agency’s strong oversight and monitoring of industry during England’s multicomponent salt reduction strategy from 2003-2010. Between 2003 and 2010, mean salt intake decreased annually by 0.20 g/day for men and 0.12 g/day for women (p <0.001). However, between 2011 and 2014, after the Responsibility Deal was implemented, annual reductions in salt intake slowed significantly to 0.11 g/day for men and 0.07 g/d for women (p <0.001). The study estimated that this shift was responsible for 9,900 additional cases of CVD and 1500 additional cases of gastric cancer between 2011 and 2018. Public-private partnerships such as the Responsibility Deal which lack target setting, monitoring, and enforcement are unlikely to produce optimal health gains.

Arcand J, Blanco-Metzler A, Benavides Aguilar K, et al. Sodium Levels in Packaged Foods Sold in 14 Latin American and Caribbean Countries: A Food Label Analysis. Nutrients. 2019;11(2):369.

In 2015, the Salt Smart Consortium released a set of sodium reduction targets for 12 categories of packaged foods throughout Latin America and the Caribbean. Targets included a regional target (maximum) level and a more aggressive lower target level (used as the goal). Overall, 82% of packaged foods in the 14 countries surveyed met the regional target level, and 47% met the lower target level. In all countries, at least of 77% of products met at least the regional target. The proportion of foods meeting the sodium targets varied, both across countries and food categories. Food categories meeting the targets most frequently included uncooked noodles and pasta, flavored cookies and crackers, seasonings, mayonnaise, and cured and preserved meats (all above 91%). Categories with the lowest proportion meeting the targets include wet and dry soups, bouillon cubes/powders, breaded meat and poultry, and cakes.

Hofman KJ, Lee R. Intersectoral case study: Successful sodium regulation in South Africa. World Health Organization Regional Office for Africa; 2013.

In 2016, South Africa began to implement mandatory regulation of sodium used in processed foods for several industries. Sodium limits were set for foods with the highest sodium, particularly bread, which contributes about 25–40% of an average South African’s daily intake of sodium, as well as for butter and margarine, savory snacks, processed meats, and soup mixes. Limits are to be phased in over a three-year period, with the first deadline in June 2016 and stricter limits in June 2019. Methods for enforcement and testing sodium levels for compliance were included in the legislation. Challenges to the process of developing this legislation, include industry pressure, concerns related to enforcement, and concerns about an expected increase in bread prices due to the reformulation costs. Regulations were made possible by intersectoral collaboration among government, academia, and industry; strong government commitment to regulating sodium; a consultation process with nutrition and hypertension-related academics, representatives of the food industry, and non-governmental organizations; and adequate consideration given to understanding industry concerns and providing “an inclusive and respectful approach”.

Curtis CJ, Clapp J, Niederman SA, et al. US Food Industry Progress During the National Salt Reduction Initiative: 2009-2014. Am J Public Health. 2016;106(10):1815-1819.

The National Salt Reduction Initiative (NSRI) is a U.S.-based coalition initiated in 2009 aimed at “reducing population sodium intake by 20%, through a reduction in sodium in US packaged and restaurant foods by 25% by 2014”. The NSRI set target levels in 61 packaged food categories for 2012 and 2014. “In 2009, when the targets were established, no categories met NSRI 2012 or 2014 targets. In 2014, 16 (26%) categories met 2012 targets and 2 (3%) met 2014 targets.” By 2014, 45% of food products had achieved the 2012 targets. From 2009 to 2014, the sales-weighted mean sodium density declined significantly by 6.8%, with reductions seen in 43% of food categories. No change was reported in restaurant food.

Alhamad N, Almalt E, Alamir N, Subhakaran M. An overview of salt intake reduction efforts in the Gulf Cooperation Council countries. Cardiovasc Diagn Ther. 2015;5(3):172-177

There has been variable progress in salt reduction efforts across countries in the Gulf Cooperation Council (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates). Intake remains high, with people in most countries consuming more than 12g/day. Efforts to reduce the salt content of bread, the major source of sodium, have been initiated in all countries. At the time of this study, only Qatar and Kuwait had made substantial progress, with a 10-20% salt reduction in bread. Challenges include “lack of political commitment, inexperience and shortage of qualified human resources”. Other regional efforts include surveillance (Kuwait, Oman, Bahrain), food labeling (Bahrain), engaging the private sector on health education (Kuwait), and reducing salt in other processed foods such as cheese and processed meats (Kuwait, Oman).

Becker MW, Bello NM, Sundar RP, et al. Front of Pack Labels Enhance Attention to Nutrition Information in Novel & Commercial Brands. Food Policy. 2015;56:76-86.

Experiments tracking participants’ allocation of attention to various iterations of front of pack label (FOPL) designs and traditional Nutrition Facts Panel (NFP) designs found that participants were more likely to detect changes to the labels with FOPL designs than NFP, meaning that the FOPL designs “garner attention more readily” than NFPs. Changes were detected even faster when FOPL designs used colors; using facial icons (smiling/frowning faces) did not have an impact on the participants’ attention.

Mora-Plazas M, Aida Higgins IC, Gomez LF, et al. Impact of nutrient warning labels on choice of ultra-processed food and drinks high in sugar, sodium, and saturated fat in Colombia: A randomized controlled trial. PLoS One. 2022. 17(2):e0263324.

An online randomized controlled trial in Colombia comparing different front-of-package label types found that a nutrient warning was more effective than GDA and Nutri-Score in discouraging Colombian consumers from wanting to purchase less healthy products, and in understanding which products had excess sugar, saturated fat, and/or sodium. In the study, over 8,000 adult participants were randomized to a nutrient warning label, guideline daily amount (GDA) label, Nutri-Score label, or no label conditions, and were surveyed on their selection choices and ability to interpret the labels. The warning label performed better on most outcomes, although the GDA label performed slightly better at helping consumers identify fruit drinks high in sugar.

Taillie LS, Bercholz M, Popkin B, et al. Changes in food purchases after the Chilean policies on food labelling, marketing, and sales in schools: a before and after study. Lancet Planet Health. 2021. 5(8):e526-e533.

This longitudinal pre-post study looked at the changes in food purchases among 2,381 Chilean households between January 2015 and December 2017, to examine the effect of the 2016 Chilean mandate of front-of pack (FOP) warning labels. The study found decreases in overall calories (164 kcal/capita/day), sugars (115 kcal/capita/day), saturated fats (22 kcal/capita/day) and salts (277 mg/capita/day) purchased after implementation of the 2016 mandate. The study also found that decreased purchases in products labeled as “high-in” certain food categories were offset by increased purchases in “not high-in” products, though not to the extent of causing a net increase in purchases of overall calories. The study is a key piece of evidence of the benefits and effectiveness of a national FOP warning label mandate.

Reyes M, Smith Taillie L, Popkin B, et al. Changes in the amount of nutrient of packaged foods and beverages after the initial implementation of the Chilean Law of Food Labelling and Advertising: A nonexperimental prospective study. PLoS Med. 2020;17(7):e1003220.

The Chilean Food Labeling and Advertising Law, implemented in 2016, mandates the use of front-of-pack warning labels for packaged foods and beverages with added sugars, saturated fats, or sodium that are above established cutoffs, in addition to prohibiting “high in” products from being marketed to children under 14 or sold/served in schools. Food label data were collected in Santiago supermarkets and compared pre- and post-implementation of the first phase of the law (warning labels required on products with >800mg sodium per 100g). After implementation of the first phase, the overall proportion of products that met the threshold for a mandatory “high in” warning label significantly decreased from 51% to 44%, mostly in food and beverage groups with regulatory cutoffs below the 75th percentile of the nutrient distribution. The proportion of “high in sodium” products (savory spreads, cheeses, ready-to-eat meals, soups, and sausages) reduced from 74% to 27% and the proportion of “high in” sugars products (beverages, milks and milk-based drinks, breakfast cereals, sweet baked products, and sweet and savory spreads) reduced from 80% to 60%. There was also a significant decrease in the amount of sodium and sugars in several groups of packaged foods and beverages (beverages, breakfast cereals, desserts and ice cream, savory spreads, and cheeses).

Do HT, Santos JA, Trieu K, et al. Effectiveness of a Communication for Behavioral Impact (COMBI) Intervention to Reduce Salt Intake in a Vietnamese Province Based on Estimations From Spot Urine Samples. J Clin Hypertens. 2016;18(11):1135-1142.

In Vietnam, about 80% of salt intake comes from table salt or salty condiments used at home. Therefore, a behavior change approach was taken to reduce population salt intake in one Vietnamese city using the Communication for Behavioral Impact (COMBI) framework. The intervention led to significant decreases in mean salt excretion both from spot and 24-hour urine samples (-0.43g/day and -1.99g/day, respectively). Significant improvements were seen for knowledge and behavioral outcomes, including increased awareness that high salt intake can cause hypertension, heart attack, and stroke and reported reductions to adding salt or sauces in the home or consuming processed foods or dishes high in salt. Mean SBP and DBP decreased significantly (5.93 mm Hg and 3.83 mm Hg, respectively), awareness of hypertensive status improved among those with hypertension (+16.3%), and fewer hypertensive subjects reported not being managed or treated (-14.2%).

He FJ, Wu Y, Feng XX, et al. School based education programme to reduce salt intake in children and their families (School-EduSalt): cluster randomised controlled trial. BMJ. 2015;350:h770. Published 2015 Mar 18.

A school-based education program on salt intake in Northern China reduced salt intake by 2.6 grams per day, a 26% reduction (−1.9 g/day in children and −2.9 g/day in adults). The intervention included health education lessons on salt reduction with interactive activities, and students were asked to take the messages home to their families, along with educational materials for the parents. The impact was assessed through a cluster-randomized control trial in 28 primary schools. Although systolic and diastolic blood pressure increased among both the control and intervention groups of adults and children by the end of the trial, the increase was less among the intervention group, with a mean effect of −1.8 mm Hg.

Land MA, Wu JH, Selwyn A, et al. Effects of a community-based salt reduction program in a regional Australian population. BMC Public Health. 2016;16:388. Published 2016 May 11.

A multi-faceted, community-based salt reduction intervention following the Communication for Behavioral Impact (COMBI) framework was implemented in Australia from 2010 to 2014. It led to significant reductions in mean salt intake of 0.8 g/day as measured by 24-hour urine. Key messages included using the FoodSwitch app, swapping table salt for a salt substitute, using spices instead of salt, and avoiding processed foods. In addition to the 24-hour urine results, significant improvements were found for most knowledge and behavioral indicators, including understanding the importance of lowering salt and using spices for flavoring or the sodium reduced, potassium-rich salt substitute which was provided.

Wentzel-Viljoen E, Steyn K, Lombard C, et al. Evaluation of a Mass-Media Campaign to Increase the Awareness of the Need to Reduce Discretionary Salt Use in the South African Population. Nutrients. 2017;9(11):1238.

For about 9 months during 2014-2015, a mass media campaign was implemented in South Africa to reduce discretionary salt intake and increase public knowledge of the dangers of high salt intake. Baseline and follow-up surveys were conducted to assess the change in knowledge, attitudes and behavior. 77.8% of the follow-up survey respondents reported having seen the SaltWatch media campaign messages. Knowledge regarding high salt intake and its health outcomes improved significantly. At follow up, “significantly more participants reported that they were taking steps to control salt intake (38% at baseline vs. 59.5% at follow up), especially for reductions in salt used in cooking and at the table, as well as higher use of herbs and spices. No significant changes were found in other behaviors, including avoiding processed foods, looking at salt/sodium labels on food, buying low-salt or low-sodium alternatives, or avoiding eating out. Data was not collected on changes in salt intake.

Sutherland J, Edwards P, Shankar B, Dangour AD. Fewer adults add salt at the table after initiation of a national salt campaign in the UK: a repeated cross-sectional analysis. Br J Nutr. 2013;110(3):552-558.

A 2003 national salt reduction campaign in the UK on salt use at the table appears to have led to a reduction in the proportion of adults who reported adding salt at the table (40.1% in 1997 to 31.7% in 2007). After the 2003 national salt reduction campaign, women were 30% less likely to add salt at the table than men (OR 0.71). Differences were also seen for geographical location, household income, and ethnicity. Adults in central and south England, high- and middle-income groups, and the non-white ethnic groups were less likely to add salt at the table than their counterparts.

Ding J, Sun Y, Li Y, et al. Systematic Review on International Salt Reduction Policy in Restaurants. Int J Environ Res Public Health. 2020;17(24):9570. Published 2020 Dec 21.

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.

Michael V, You YX, Shahar S, et al. Barriers, Enablers, and Perceptions on Dietary Salt Reduction in the Out-of-Home Sectors: A Scoping Review. Int J Environ Res Public Health. 2021. 18(15):8099.

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.

Ma J, Lee S, Kim K, Lee YK. Sodium reduction in South Korean restaurants: A Daegu-based intervention project. Asia Pac J Clin Nutr. 2020;29(2):404-413.

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.

Ma GX, Shive SE, Zhang G, et al. Evaluation of a Healthy Chinese Take-Out Sodium-Reduction Initiative in Philadelphia Low-Income Communities and Neighborhoods. Public Health Rep. 2018;133(4):472-480.

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.

Anekwe AV, Lent M, Farley SM, et al. New York City’s Sodium Warning Regulation: From Conception to Enforcement. Am J Public Health. 2019;109(9):1191-1192.

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.

Musicus AA, Moran AJ, Lawman HG, Roberto CA. Online Randomized Controlled Trials of Restaurant Sodium Warning Labels. Am J Prev Med. 2019;57(6):e181-e193.

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.

World Health Organization. Action framework for developing and implementing public food procurement and service policies for a healthy diet. Geneva, World Health Organization (WHO), 2021.

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.

Niebylski ML, Lu T, Campbell NR, et al. Healthy food procurement policies and their impact. Int J Environ Res Public Health. 2014;11(3):2608-2627.

“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.

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.

Country Examples

Lederer A, Curtis CJ, Silver LD, Angell SY. Toward a healthier city: nutrition standards for New York City government. Am J Prev Med. 2014;46(4):423-428.

In 2008, New York City Mayor Bloomberg signed an Executive Order which led to the development of the NYC Standards for Meals/Snacks Purchased and Served, a policy requiring all city agencies to follow the standards (including limits for sodium) for all food that is purchased, prepared, and/or served by the agency, covering more than 260 million meals and snacks per year. The standards were developed by a Food Procurement Workgroup, with representation from all relevant city agencies and the NYC Health Department serving as technical advisor. Elements which led to successful implementation of the standards included support from a high-level central authority, providing extensive technical assistance to agencies, incorporating the standards into all city agency contracts which involved food, and developing regular progress reports detailing agencies’ compliance with the standards.

Gase LN, Kuo T, Dunet D, et al. Estimating the potential health impact and costs of implementing a local policy for food procurement to reduce the consumption of sodium in the county of Los Angeles. Am J Public Health. 2011;101(8):1501-1507.

This study modeled the potential costs and effects on daily sodium consumption and related health outcomes of reducing the sodium content in food served in six types of public settings operated by the government of Los Angeles County, California. In total, the policy would affect 13,183 adults and 24,000 children who are served by venues operated by Los Angeles County (notably schools were not included). The average daily sodium consumption would be reduced between 220 mg (6% reduction) and 773 mg (23% reduction), depending on the settings and approach used. Systolic blood pressure reductions among adults would fall between 0.45-1.59 mmHg, leading to a 5% decrease in the prevalence of uncontrolled hypertension, as well as an annual $629,724 savings in direct health care costs. The estimated 1 -year start-up costs for Los Angeles County to implement the policy ranged from $227,753 to $1,723,539, based on the uncertainty regarding the potential changes in food costs.

Examples by specific venues

Schools

Ellison RC, Capper AL, Stephenson WP, et al. Effects on blood pressure of a decrease in sodium use in institutional food preparation: the Exeter-Andover Project. J Clin Epidemiol. 1989;42(3):201-208.

A six-month boarding school intervention to reduce sodium intake through changes to food purchasing and preparation led to a 15-20% reduction in sodium intake at the two participating schools. No information or directives were given to students throughout the intervention. The two schools each served as an intervention and control site during alternating years. Students selected for monitoring were asked to keep a 24-hour food diary once a week at scheduled intervals during the intervention and measured their blood pressure at the beginning and end of the school year. After adjusting for sex and initial blood pressure, “the net effect on both systolic and diastolic blood pressure produced by the 24 weeks of dietary intervention is estimated at approximately -1.0 mmHg for males and -2.5 mmHg for females”.

Spence S, Delve J, Stamp E, et al. The impact of food and nutrient-based standards on primary school children’s lunch and total dietary intake: a natural experimental evaluation of government policy in England. PLoS One. 2013;8(10):e78298.

In 2006, food- and nutrient-based standards were mandated for primary schools in England. A study at 12 primary schools found that the standards were “associated with significant improvements in the nutritional content of school lunches.” Post-implementation, mean daily intake of sodium fell by 67 mg per day. Children who ate the school lunch consumed less sodium (-128 mg) than children eating a packed lunch. Additional improvements were seen in reduced energy, absolute intakes of fat, saturated fat, and non-milk extrinsic sugars in packed and school lunches. Children who ate school lunches had “a lower percent energy derived from fat and saturated fat, but more carbohydrate, protein, non-starch polysaccharides, vitamin C and folate in their total diet than children who ate a packed lunch”.

World Food Programme. Smart School Meals: Nutrition-sensitive national programmes in Latin America and the Caribbean. 2017.

Nearly all countries in the Latin America and the Caribbean region implement school meals programs; however, “despite undisputed achievements and progress, the nutritional potential of school meals is often underutilized”. Many of these programs could be strengthened by incorporating specific nutrition criteria to limit unhealthy nutrients such as salt, fats, and sugar.

Hospitals

Moran A, Lederer A, Johnson Curtis C. Use of Nutrition Standards to Improve Nutritional Quality of Hospital Patient Meals: Findings from New York City’s Healthy Hospital Food Initiative. J Acad Nutr Diet. 2015;115(11):1847-1854.

The New York City Health Department implemented the Healthy Hospital Food Initiative (HHFI) from 2010-2014, which included nutrient-based food procurement standards and standards for patient meals. A study comparing the nutritional composition of regular-diet patient meals in 8 hospitals before and after the initiative found that “Median sodium content decreased 19%, from 2,636mg to 2,149mg per day.” Additionally, fiber increased by 25%, the percentage of calories from fat decreased by 24% and from saturated fat by 21%, and daily dessert offerings decreased 92%. At follow-up, nutrition content across all hospital menus improved and either met or exceeded the minimum HHFI standards.

Ministry of Health, Population and Public Health, British Columbia. Sodium Reduction in Health-Care Facilities: B.C.’s Experience. 2016.

The British Columbia health authority developed and implemented provincial sodium guidelines and procurement policies for food service operations in BC government health care facilities between 2011 and 2016. The initiative was carried out in three phases: 1) developing sodium guidelines and procurement policies (5 months), 2) stakeholder engagement and implementation (3 years), and 3) final push to reach the target of 2300mg per day/meal (adults) and 1818-2300 mg (pediatric) (1 year). Results showed that by 2016, adult meals had 28% less sodium than at baseline (3372mg to 2372mg), although the final reduction target of 2300mg was not met. Due to various implementation, the date for reaching the target levels was extended to 2021, and sodium targets were lowered to 2,300 – 2,700 mg during the interim.

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 Salt Substitute and Stroke Study (SSaSS) 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.

Bernabe-Ortiz A, Sal Y Rosas VG, Ponce-Lucero V, et al. Effect of salt substitution on community-wide blood pressure and hypertension incidence. Nat Med. 2020;26(3):374-378.

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.

Li N, Yan LL, Niu W, et al. The Effects of a Community-Based Sodium Reduction Program in Rural China – A Cluster-Randomized Trial. PLoS One. 2016;11(12):e0166620.

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.

Li KC, Huang L, Tian M, et al. Cost-Effectiveness of a Household Salt Substitution Intervention: Findings From 20 995 Participants of the Salt Substitute and Stroke Study. Circulation. 2022. 145(20):1534-1541.

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.

Marklund M, Singh G, Greer R, et al. Estimated population wide benefits and risks in China of lowering sodium through potassium enriched salt substitution: modelling study. BMJ. 2020;369:m824.

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.

Murphy MM, Scrafford CG, Barraj LM, et al. Potassium chloride-based replacers: modeling effects on sodium and potassium intakes of the US population with cross-sectional data from NHANES 2015-2016 and 2009-2010. Am J Clin Nutr. 2021 Jul 1;114(1):220-230.

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.

World Health Organization Regional Office for Europe, National Institute for Food and Nutrition Science. Assessment of the impact of a public health product tax, Final report. Budapest. 2015.

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.

Batis C, Rivera JA, Popkin BM, Taillie LS. First-Year Evaluation of Mexico’s Tax on Nonessential Energy-Dense Foods: An Observational Study. PLoS Med. 2016;13(7):e1002057. Published 2016 Jul 5.

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.

Cobiac LJ, Tam K, Veerman L, Blakely T. Taxes and Subsidies for Improving Diet and Population Health in Australia: A Cost-Effectiveness Modelling Study. PLoS Med. 2017;14(2):e1002232.

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.