This bibliography is intended as a resource to support the design and implementation of national sodium reduction programs, and is useful for policy development, surveillance of population sodium sources and intake, and implementation of sodium reduction efforts. The aim is to provide a brief overview of the scientific basis of key aspects of sodium reduction strategies. This list is not representative of all aspects of sodium reduction and is largely drawn from the scientific literature published in English.
The bibliography is organized into four sections: first, a general overview of the consequences of sodium consumption and strategies for reduction; next, a review of the science behind salt reduction; third, surveillance strategies for measuring sources of sodium and population intake of sodium; and finally, a review of the various strategies recommended for large scale population sodium reduction.
Salt consumption is likely the major factor for increasing population blood pressure. Multiple studies show that populations with successful reductions in salt consumption also reduced blood pressure as well as other adverse health outcomes, particularly cardiovascular disease. Despite this strong evidence, many countries have not yet developed a salt reduction plan. A few countries such as Finland, Japan, and the UK have successfully implemented large-scale salt reduction programs through strategies such as industry engagement for product reformulation and labeling or through public health education.
In the United States, high blood pressure is the leading cause of cardiovascular disease deaths, and 90% of the population consumes too much sodium. Clear evidence from rigorous studies shows the benefit of sodium reduction on reducing blood pressure. Even small reductions in sodium intake can have great effects on hypertension prevalence, and likely on mortality from cardiovascular disease as well. “Over a decade, (a reduction of 1200 mg/d) could prevent up to an estimated 500000 deaths and may save an estimated $100 billion in health care costs.” Sodium reduction is unlikely to harm any segment of the population. This article advocates for the immediate implementation of the proposed US guidelines that would set voluntary sodium targets for industry.
The 2017 Global Burden of Disease study estimated that global consumption of sodium was 6g per day. High intake of sodium caused approximately 3 million deaths and 70 million disability-adjusted life-years (DALYs) in 2017. High intake of sodium was the leading dietary risk factor for mortality among men and was the leading risk for deaths and DALYs among older adults (≥70 years). It was also found to be the leading dietary risk factor for deaths and DALYs in east Asia and high-income Asia Pacific regions. Countries ranking high-middle and middle on the Socio-Demographic Index (SDI) were at the greatest risk of deaths and DALYs from high intake of sodium. For all countries except those at low SDI, sodium intake was one of the four leading dietary risks.
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This systematic review evaluates recent literature on the association between salt intake and health outcomes. Most studies published since 2015 do not address the research gaps or meet the recommendations for research methods outlined in the 2013 Institute of Medicine report on the scientific evidence on sodium and health outcomes. Reasons for this could include a lack of knowledge about the recommendations, resources necessary, or time for implementation and reporting. Most of the published evidence on sodium and CVD risk between 2015 and 2019 was observational (a high number were cross-sectional) rather than interventional, thus subject to potential bias from error in assessment of sodium intake and confounding. Observational studies with clinical end points (CVD, mortality, etc.) had mixed results (positive, null, and negative). Further research is required, particularly RCTs examining the effects of sodium on CVD outcomes among the general population and for specific populations that are at higher risk, including chronic heart failure patients.
WHO recommends that adults consume less than 2,000 mg of sodium, or 5 grams of salt per day. WHO also recommends a reduction in sodium intake to control blood pressure in children. For children, the recommended maximum for adults should be adjusted downward based on energy requirements of children relative to those in adults. A diet high in sodium increases the risk of raised blood pressure and increases the risk of heart disease and stroke. Reducing sodium intake significantly reduces blood pressure in both children and adults and has no adverse effects on blood lipids or renal function.
WHO recommends that adults consume at least 3150 mg of potassium per day to reduce systolic and diabolic blood pressure and risk of cardiovascular disease in adults. An increase in potassium intake from food is also suggested for control of blood pressure in children. Evidence suggests that higher potassium intake has no adverse effect on blood lipids or renal function in adults but can decrease risk of cardiovascular disease, have beneficial effects on bone mineral density, and mitigate the negative effect of high sodium consumption. An uptake in potassium consumption can be achieved through the increased consumption of food high in potassium such as fresh fruit, vegetables, and beans.
The DASH sodium study randomized participants to be fed three different sodium levels (3,400, 2,300 and 1,150 mg/day) of either the DASH diet (diet rich in fruits, vegetables, and low-fat dairy products, including whole grains, poultry, fish, and nuts) or a typical diet for 30 days at each sodium level. Among participants on the typical diet, those randomized to intermediate and low sodium levels saw a significant reduction in systolic BP of 2.1 mmHg and 6.7mmHg, respectively. Participants randomized to the DASH diet had even greater decreases in blood pressure at the low sodium levels. Compared to the typical diet group with high intake, they achieved systolic BP decreases of 7.1mm Hg (without hypertension) and 11.5 mm Hg (with hypertension). Both diets showed a progressive effect, with greater decreases in BP with further reductions in sodium intake.
Across 52 locations in 32 countries, median urinary sodium excretion values ranged from 4.6 mg/24 h to 5,568.3 mg/24 h. In the four study sites with very low sodium excretion, blood pressure was also found to be low, and there was no significant age-related rise in blood pressure. There was a linear relationship between the median 24-hour urinary sodium excretion and the slope of systolic and diastolic BP with age. After adjustment for body mass index and alcohol intake, all sites demonstrated this same relationship.
“A 100 mmol reduction in 24-hour urinary sodium (~6 g/day salt) was associated with a fall in systolic blood pressure of 5.8 mm Hg (2.5 to 9.2, P=0.001) after adjustment for age, ethnic group, and blood pressure status”. Additionally, data from the two trials that compare multiple salt intake levels over time suggest a dose-response relationship with salt intake and BP, with larger salt reductions resulting in greater BP decreases. Reducing salt intake from the average of the analyzed trials (9.4 g/day) to 5-6 g/day would have significant impacts on lowering blood pressure, but reductions to 3 g/day would provide even greater benefits.
For similar article, see:Filippini T, Malavolti M, Whelton PK, et al. Blood Pressure Effects of Sodium Reduction: Dose-Response Meta-Analysis of Experimental Studies. Circulation. 2021. 143,16: 1542-1567.
Using participants from a 1980 Dutch study that showed that “sodium intake was positive related to BP during the first 6 months of life”, this current study demonstrated that sodium intake during infancy may be associated with blood pressure later in life. Fifteen years after the 1980 study, 35% (167) of the original participants were selected for follow up. Compared to the control group (normal sodium intake), the low sodium intake group had 3.6 mm Hg lower systolic blood pressure (−6.6 to −0.5, p=.02) after controlling for confounding factors. Significant differences were not reported between groups for urinary sodium excretion.
A pooled analysis of 6 major prospective cohort studies which collected multiple gold standard 24-hour urine samples found a significant linear, dose-response association between sodium intake and cardiovascular risk between 2,000 mg and 6,000 mg sodium/day. The study included 10,000 generally healthy adults followed for an average of 8.8 years. Higher potassium intake and a lower sodium-to-potassium ratio were also associated with significantly lower levels of cardiovascular disease. For every 1,000 mg per day increase in sodium excretion, a person's risk for cardiovascular disease rose by 18%; a 1,000 increase in potassium excretion decreased cardiovascular risk by 18%. Sodium intake was also positively associated with cardiovascular mortality (but not all cause mortality). Both higher potassium excretion and a lower sodium-to-potassium ratio were associated with a lower risk of all-cause mortality, including cardiovascular risk. Though many cohort studies have found J or U-shaped relationships between sodium intake and cardiovascular risk, these have primarily relied upon spot urine collection and occasionally a single 24-hour urine collection. This is the first meta-analysis to include only the gold standard of multiple 24-hour urine collections.
For similar articles, see:Wang YJ, Yeh TL, Shih MC, et al. Dietary Sodium Intake and Risk of Cardiovascular Disease: A Systematic Review and Dose-Response Meta-Analysis. 2020. Nutrients. 12,10 2934. Aburto NJ, Ziolkovska A, Hooper L, et al. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ. 2013;346:f1326.
One of the few trials assessing the impact of sodium intake on CVD, this study used long-term follow-up data from 3,126 prehypertensive adult participants of the trials of hypertension prevention (TOHP) to determine effects on cardiovascular disease outcomes. Participants were randomized to a control group or a sodium reduction intervention group lasting 18 months (TOHP I) or 36-48 months (TOHP II). The intervention groups showed a 30% reduction in cardiovascular disease and a 20% reduction in mortality compared to the control groups.
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.”
A pooled analysis from four prospective studies, including both healthy adults and adults with high risk of diabetes, vascular disease, or hypertension, found a U-shaped association between sodium excretion and cardiovascular events and mortality for individuals with hypertension. High sodium excretion (>7g/day) and low sodium excretion (<3g/day) were both associated with increased risk of cardiovascular disease events or all-cause mortality compared to those with sodium excretion of 4-5 g/day. For those without hypertension, only low sodium excretion (<3 g/day) was associated with a significantly increased risk. 24-hour sodium excretion was estimated based on spot urines.
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.
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.
For similar articles, see: Cobb LK, Anderson CA, Elliott P, et al. Methodological issues in cohort studies that relate sodium intake to cardiovascular disease outcomes: a science advisory from the American Heart Association. Circulation. 2014;129(10):1173-1186.Cogswell ME, Mugavero K, Bowman BA, Frieden TR. Dietary Sodium and Cardiovascular Disease Risk--Measurement Matters. N Engl J Med. 2016;375(6):580-586.He FJ, Campbell NRC, Woodward M, et al. Salt reduction to prevent hypertension: the reasons of the controversy. Eur Heart J. 2021. 42,25: 2501-2505.
Campbell NRC, He FJ, Cappuccio et al. Dietary Sodium 'Controversy'-Issues and Potential Solutions. Curr Nutr Rep. 2021 10,3: 188-199.
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.
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.
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).
Both reduced sodium intake and increased potassium intake have been reported to reduce blood pressure. This systematic review concluded that “the sodium-to-potassium ratio (Na-K ratio) is more strongly associated with blood pressure outcomes than either sodium or potassium alone in hypertensive populations”.
Reducing unhealthy diets through reducing salt intake is considered a “Best Buy intervention” by the WHO. Recommended interventions to reduce salt intake include reformulation of food products, establishing a supportive environment in public institutions by providing low-salt options, education through behavior change communication and mass-media campaigns, and front-of-pack labelling. Investment in salt reduction activities offers the highest return among all Best Buy interventions, an estimated US$12.82 return on every US$1 invested.
Following the 2013 World Health Assembly, global commitments were made to reach a 25% relative reduction in premature mortality from non-communicable diseases (NCDs) by 2025. This study estimates that achieving the targets for six risk factors, including a 30% reduction in salt intake (others include tobacco and alcohol use, obesity, and raised blood pressure and glucose), would result in a decreased probability (-22% in men, -19% in women) of dying from any of the four major NCDs (cardiovascular diseases, chronic respiratory diseases, cancers, and diabetes).
In a global modeling study across 183 countries, the cost effectiveness of a 10-year government “soft regulation” policy consisting of combined targeted industry agreements and public education to reduce population sodium consumption by 10% was approximately I$204 per DALY saved with a population weighted mean cost of I$1.13 per capita. Nearly 5.8 million DALYs/year related to CVD would be averted. Cost effectiveness estimates widely ranged by country; however, in all but one country the interventions were cost effective as per the WHO benchmark (<3×GDP per capita).
Using 24-hour urinary sodium data from the 2011 SMASH study, authors estimated the annual number of CVD-related deaths in Shandong province attributable to high sodium intake and modelled the number of lives potentially saved through a 30% reduction in sodium intake. High sodium intake (>2000mg/day) was estimated to account for an estimated 16,000 CVD-related deaths in 2011 among those aged 25-69 (or nearly 20% of total CVD deaths) in Shandong. With a 30% reduction in sodium intake, Shandong province could potentially avert 8,800 sodium attributed CVD deaths, and with the SMASH sodium reduction goal of 4g/day, 6,700 sodium attributed deaths could be averted.
Authors conducted a cost-effectiveness analysis to assess the South African Government policy to lower population salt intake to 5g per person/day by regulating salt in processed foods and conducting media campaigns. The policy would avert approximately 5,600 deaths and 23,000 cases of CVD yearly (11% of CVD deaths). It would also save US$ 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.
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.
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.
For similar article, see: Rubinstein A, Martí SG, Souto A, et al. Generalized cost-effectiveness analysis of a package of interventions to reduce cardiovascular disease in Buenos Aires, Argentina. Cost Eff Resour Alloc. 2009 May 6;7:10.
Dietary salt preference largely stems from one’s individual salt intake habits. Those who consume high sodium levels prefer the taste of high salt. This review paper highlights findings such as the impact of early exposure to salty foods in determining salt preference later in life, the ability for salt preference to change over time after limiting exposure, and the tendency not to overcompensate for low-sodium foods by adding salt at the table. Gaps in the research are also discussed, such as whether children’s salt preference can be shifted and why humans desire and consume salt in the absence of biological need.
When sodium was reduced by nearly 50% in foods served to study participants, participants only added 20% back with a salt shaker at the table. Throughout the study, participants did not report any changes in taste perception.
“[S]alt can be reduced in breads and processed meats by up to 37% and 67%, respectively, without a decrease in consumer acceptability.” For cheese products, meta-analysis showed decreasing levels of acceptance with reduced amounts of salt. Acceptance was lower in studies with salt reduction above 60%. Results varied for other products. Acceptability of products using low-sodium salts or flavor compensation were also studied. Replacing up to 50% of salt with potassium chloride in meat products or up to 30% in cheese was not found to impact acceptability.
Because many populations primarily consume iodine through salt fortification, there is concern that reduction of salt intake will lead to inadequate consumption of iodine. Iodine fortification has been a major and successful public health initiative over the past 2-3 decades. Thus, it is important that progress in this area is not hindered but complemented by salt reduction strategies.
Programs and policies for salt iodization and salt reduction can and should go hand in hand as a strategy to reduce the burden of hypertension and cardiovascular disease. Both require food industry and service operator engagement and similar surveillance modalities, making it possible to jointly implement both initiatives. Suggested key activities include coordinating policy development and implementation through regulatory policies, such as adjusting the iodine concentration in salt given a population sodium intake and regulating sodium levels in processed foods. Coordinated monitoring and surveillance of iodine and sodium intake through joint surveys and evaluations is recommended, managed by cross disciplinary research programs. Communication and advocacy efforts should also be conducted jointly, as well as investment, to maximize the effectiveness and reach of both programs.
This modeling study in a Dutch population found that salt reductions of 12, 25 or 50% in industrially processed foods decreased mean salt intake by 7, 15 and 30% compared with current intake, and mean iodine intake by 6, 12 or 25%. Iodine intake levels remained adequate at all salt reduction levels for most the population. Reducing both discretionary salt and salt in industrial foods by 50%, led to a slight increase (1-11%) in inadequate iodine intakes for age groups above 3 years. For children aged 1-3 years, all scenarios led to inadequate iodine levels, affecting between 10% (12% industrial reduction) to 35% of the population (50% reduction industrial + discretionary). However, if industry meets the target of using iodized salt in 50% of industrially processed foods, there would be “adequate iodine intakes for virtually the whole population, including young children” for all scenarios.
In this cohort study of older South Africans, salt intake (measured by 24-hour urine) was positively associated with 24-hour iodine excretion (p<0.001). Those in the lowest salt intake category (<5g/day) did not meet iodine requirements (95 μg/day). Salt reduction programs may need to be accompanied by further iodine fortification efforts, and intake of both nutrients should be monitored simultaneously.
In an RCT, a ~3.5-month school-based educational salt reduction program in northern China led to a significant decrease in salt intake of 1.9 g/day in children and 2.9 g/day in adults. Although iodine intake also decreased (19.3% in children and 11.4% in adults), iodine intake remained adequate.
For similar articles, see:Campbell NR, Dary O, Cappuccio FP, Neufeld LM, Harding KB, Zimmermann MB. Need for coordinated programs to improve global health by optimizing salt and iodine intake. Rev Panam Salud Publica. 2012;32(4):281-286
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.
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.
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.
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).
For similar article, see:Santos JA, Li KC, Huang L, Mclean R, Petersen K, Di Tanna GL, Webster J. Change in mean salt intake over time using 24-h urine versus overnight and spot urine samples: a systematic review and meta-analysis. Nutrition journal. 2020 Dec;19(1):1-2.
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.
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”.
Using 24-hour urine-based and diet-based surveys from 66 countries (61% high-income regions, 40% low- or mid-income regions), authors estimated a mean level of global sodium consumption of 3.95g per day (or 10.06g/day of salt) as of 2010 (regional mean levels ranged from 2.18 to 5.51g sodium per day), with 99.2% of adults worldwide exceeding recommended level of 2.0g/day and 88.3% exceeding the recommended level by more than 1.0g/day. Men had slightly higher intake than women (4.14g/day vs 3.7g/day). Variation by age was small. Highest intakes were found in Asia (East Asia: 4.8g/day, Asia Pacific (high income): 5.0g/day, and Central Asia 5.51g/day. Next highest were Eastern Europe (4.18g/day), Central Europe (3.92g/day), and the Middle East and North Africa (3.92g/day). Lowest intakes were found in Sub-Saharan Africa, Latin America and the Caribbean and Oceania, although data was limited in these areas. A statistically non-significant increase in sodium intake globally was found using 24-hour urine data between 1990 and 2010.
Knowing the main sources of dietary salt in a country is essential for the development of effective salt reduction interventions. To determine baseline data on the major contributors to salt intake, authors recommend determining the level of discretionary salt in the household by a combination of direct and indirect methods (e.g., qualitative surveys or interviews, household food disappearance studies, “subtraction” methods), determining food consumption patterns through established survey instruments (if they exist) or by 24-hour recalls or food frequency questionnaires, and identifying the proportional importance of discretionary sources versus commercially prepared foods. They emphasize the importance of directing resources toward maintaining national or international food composition databases, either from primary or secondary sources.
This review identifies the sources of dietary salt in all countries with available data. The average daily salt intake of adults in these studies ranged from 5.2 in Guatemala to 15.5 g/day in China. Brazil, China, Costa Rica, Guatemala, India, Japan, Mozambique, and Romania appear to obtain more than half of their daily salt during cooking or at the table (discretionary salt). Populations in Jordan, Portugal, South Korea, Taiwan, and Turkey appear to receive between 25 and 50% of their daily salt from discretionary sources. On the other hand, discretionary salt intake accounts for less than 25% of daily salt intake in Australia, Austria, Canada, Denmark, Finland, New Zealand, the United Kingdom, and the United States of America. While there were no obvious regional patterns in the food sources of dietary salt, bread and bakery products, cereal and grain products, meat products, and dairy products appeared to be the main global contributors to daily salt intake. The study additionally found a significant inverse correlation between a country's GDP per capita and the proportion of daily salt intake from discretionary sources.
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.
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.
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.
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
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.
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.
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.
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.
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.
For other similar articles from China, see: Shao S, Hua Y, Yang Y, et al. Salt reduction in China: a state-of-the-art review. Risk Manag Healthc Policy. 2017;10:17-28.
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.
Fiji implemented a 20-month national salt reduction intervention between 2014-2015 including strategic health communication (through a health educator training program and a public awareness campaign); a hospital program (education and reducing salt in meals); and engagement of food manufacturers and food retailers to voluntarily lower the salt content of foods, use reduced salt products, and remove salt shakers from tables. To assess the impact, 24-h urine samples were taken before and after the 20-month intervention. Sodium intake decreased from 11.7g/day to 10.3g/day, which was not statistically significant (p=0.115).
For other country implementation articles, see: Enkhtungalag B, Batjargal J, Chimedsuren O, et al. Developing a national salt reduction strategy for Mongolia. Cardiovasc Diagn Ther. 2015;5(3):229-237.
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.
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.
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.
“(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.
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.
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.
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”.
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).
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.
Shangguan S, Afshin A, Shulkin M, et al. A Meta-Analysis of Food Labeling Effects on Consumer Diet Behaviors and Industry Practices. AJPM. 2018 Dec 17.
Roberto CA, Ng SW, Ganderats-Fuentes M, et al. The Influence of Front-of-Package Nutrition Lableing on Consumer Behavior and product Reformulation. Annu Rev Nutr. 2021. 41:22.1–22.22
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.
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.
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.
For similar articles, see:Arrúa A, Machín L, Curutchet MR, et al. Warnings as a directive front-of-pack nutrition labelling scheme: comparison with the Guideline Daily Amount and traffic-light systems. Public Health Nutr. 2017;20(13):2308-2317.
Bopape M, De Man J, Taillie LS, et al. Effect of different front-of-package food labels on identification of unhealthy products and intention to purchase the products- A randomised controlled trial in South Africa. Appetite. 2022 Dec 1;179:106283.
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.
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).
*For other Chile papers, see:
Food and Agriculture Organization of the United Nations, Pan American Health Organization, World Health Organization. Approval of a new Food Act in Chile: Process Summary. FAO/WHO. Santiago. 2016. (Describes the contents and regulatory process of Chile’s Food Labeling and Advertising Law)
Massri C, Sutherland S, Källestål C, Peña S. Impact of the food-labeling and advertising law banning competitive food and beverages in Chilean public schools, 2014–2016. American journal of public health. 2019 Sep;109(9):1249-54.
Reyes M, Garmendia ML, Olivares S, Aqueveque C, Zacarías I, Corvalán C. Development of the Chilean front-of-package food warning label. BMC Public Health. 2019;19(1). doi:10.1186/s12889-019-7118-1.
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.
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%).
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.
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.
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.
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.
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.
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 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.
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.
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.
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”.
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”.
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.
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.
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.
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.
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.
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.
For similar article, see: Brand A, Visser ME, Schoonees A, Naude CE. Replacing salt with low‐sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women. Cochrane Database of Systematic Reviews 2022, Issue 8. Art. No.: CD015207.
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.
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.
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.
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.
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.
For similar article, see: Hernández-F M, Batis C, Rivera JA, et al . Reduction in purchases of energy-dense nutrient-poor foods in Mexico associated with the introduction of a tax in 2014. Prev Med. 2019. 118:16-22.
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.
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.
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.
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.
Nutrient profile models (NPMs) classify or rank food and drink products according to their nutritional composition and can be used to identify foods which are in excess of critical nutrients such as sugars, sodium, and saturated fats. NPMs can underpin a variety of nutrition policy interventions, such as marketing of foods to children, health and nutrition claims, product labelling logos or symbols, information and education, public food procurement, and fiscal policies.
A systematic review found 78 existing nutrient profiling models (NPM) with applications in government nutrition policies. In the past 10 years, adoption of NPMs in government-led policies has increased, including NPMs adapted from existing models from other countries (44% of models were adaptations of one or more other models). All models included nutrients to limit, most frequently sodium, saturated fat, and total sugars. 86% of models also considered nutrients to encourage (e.g. fiber). The most common NPM applications were regulating food in public and other settings (43/78), food labeling (front-of-package labeling or regulating claims) (19/78) and restriction of the marketing of food products to children (10/78). Most models (71/78) provided summary ratings of the nutritional quality of food products based on the amounts of ≥2 nutrients or food components, while 3/78 used nutrient specific thresholds. This article may be used to assist stakeholders in the selection of an appropriate NPM for establishing certain nutrition-related policies or regulation.
This study presents a model to simplify the various choices required to develop a nutrient profile model (NPM) and to compare NPMs across countries. The key choices which are made when developing a scheme and selecting nutrients to include, are: 1) whether the system is based on specific food categories or ‘across the board’ amounts, 2) whether the NPM qualifies nutrients for and encourages consumption (e.g., vitamin C or fiber), or disqualifies ingredients aiming to reduce consumption (e.g., sugar, sodium, trans fat). 3) which reference to use (amount of nutrient per 100g/100 ml, 100 kcal/100 kJ, or per serving), and 4) whether to use a scoring system (ranking products by how healthy or unhealthy they are) or a threshold system (an either-or system). Also, the study provides examples of completed models comparing the US, UK, Sweden, the Netherlands, and industry NPM systems.
This article maps the process South Africa took to develop a nutrient profile model (NPM) suitable to the South African food supply and population that could underpin nutrition policies in that have proven successful in other countries, such as front-of-package labeling, marketing restrictions, taxation policies, and public food procurement. The process included: 1) determining the NPM’s purpose and target population, 2) selecting the appropriate nutrients to be included in the NPM, 3) determining the most suitable NPM type, criteria, and base unit of measure (e.g., per 100g/ml), and 4) selecting reasonable thresholds. Unhealthy processed packaged foods were chosen as the target they are the key drivers of diet-related NCDs in South Africa. The target population was adults and children over 6 months old. To determine which existing NPM to adapt and the nutrients to include, other NPMs were mapped against the food supply in South Africa. The ‘nutrients to limit’ chosen included saturated fat, sodium, non-sugar sweetener, and total sugar. The Chile 2019 NPM, with its across-the-board threshold on the basis of nutrient values per 100g/mL was identified as the most suitable model to adapt. The thresholds were adopted as-is for sodium, saturated fat and total sugar. Ultimately, the NPM performs well at identifying unhealthy products, and thus will be appropriate to use for future nutrition policies.
The thresholds defined by the WHO SEARO Nutrient Profile Model (NPM) can be used by the Indian government as the basis for developing a front-of-pack labelling (FOPL) regulation in India in hopes of reducing the growing burden of nutrition-related non-communicable diseases. The study applies both the SEARO NPM and the Chilean Warning Octagon (CWO) Phase 3 NPM to a database of food products available in the Indian market from 2015 to 2020 (n=10501 products). A previous study conducted with a much smaller sample size (n= 3316) concluded that he WHO SEARO model was too strict for use in India as 96% of the sample would meet the criteria for at least one warning label. With this larger and more comprehensive sample size, applying the SEARO model resulted in only 68% percent of products meeting the criteria for at least one warning label, and 63% meeting the Chilean model criteria.
For similar article, see: Frank T, Ng SW, Miles DR, et al. Applying and comparing various nutrient profiling models against the packaged food supply in South Africa. Public Health Nutr. 2022. 25(8):2296-2307.