The Science of Salt: A global review on changes in sodium levels in foods

Metals on the Menu-Analyzing the Presence, Importance, and Consequences

Metals are integral components of the natural environment, and their presence in the food supply is inevitable and complex. While essential metals such as sodium, potassium, magnesium, calcium, iron, zinc, and copper are crucial for various physiological functions and must be consumed through the diet, others, like lead, mercury, and cadmium, are toxic even at low concentrations and pose serious health risks. This study comprehensively analyzes the presence, importance, and consequences of metals in the food chain. We explore the pathways through which metals enter the food supply, their distribution across different food types, and the associated health implications. By examining current regulatory standards for maximum allowable levels of various metals, we highlight the importance of ensuring food safety and protecting public health. Furthermore, this research underscores the need for continuous monitoring and management of metal content in food, especially as global agricultural and food production practices evolve. Our findings aim to inform dietary recommendations, food fortification strategies, and regulatory policies, ultimately contributing to safer and more nutritionally balanced diets.

Accuracy of Declared Salt Content on Traffic Light Labelling of Nuts and Seeds in Isfahan, Iran

BACKGROUND

Regarding the importance of the prevention of non-communicable diseases (NCDs) and higher consumption of salt among the Iranian population than the level recommended by the World Health Organization, the aim of this study was to evaluate the accuracy of the salt mentioned in the traffic light labelling of nuts and seeds. Study Design: A cross-sectional study.

METHODS

A total of 53 packaged nuts and seeds, including 7, 8, 9, 9, 10, and 10 samples of pumpkin, pistachios, almond, sunflower, peanut, and watermelon nuts and seeds, respectively, with traffic light labelling, were randomly purchased from several local markets in Isfahan, Iran. The amount of sodium was measured by the inductively coupled plasma-optical emission spectroscopy technique and then multiplied by 2.5 to achieve the amount of salt.

RESULTS

Varying levels of traffic light labeling value accuracy were observed in most of the samples. In the almond, pistachio, peanut, and watermelon groups, the average amount of laboratory value had a statistically significant difference with the label value (P<0.05).

CONCLUSION

The results demonstrated that the salt content of 82% of the studied samples had discrepancies with the values stated on the traffic light labelling. The presentation of an accurate amount of salt content is essential for promoting healthy eating habits and enabling individuals to make informed choices about their diet. It is recommended that regulatory authorities should review labelling guidelines and enforce stricter compliance to ensure accurate representation of salt content on packaged foods.

Sodium and Human Health: What Can Be Done to Improve Sodium Balance beyond Food Processing?

Sodium plays a key role in the regulation of water balance and is also important in food formulation due to its contribution to the taste and use in the preservation of many foods. Excessive intake of any essential nutrient is problematic and this seems to be particularly the case for sodium since a high intake makes it the nutrient most strongly associated with mortality. Sodium intake has been the object of recommendations by public health agencies such as the WHO and this has resulted in efforts by the food industry to reduce the sodium content of packaged foods, although there is still room for improvement. The recent literature also emphasizes the need for other strategies, e.g., regulations and education, to promote adequate sodium intake. In the present paper, we also describe the potential benefits of a global healthy lifestyle that considers healthy eating but also physical activity habits that improve body functionality and may help to attenuate the detrimental effects of high sodium intake on body composition and cardiometabolic health. In conclusion, a reduction in sodium intake, an improvement in body functioning, and educational interventions promoting healthy eating behaviours seem to be essential for the optimal regulation of sodium balance.

Changes in the Sodium Content in Branded Foods in the Slovenian Food Supply (2011-2020)

High sodium intake is the leading diet-related risk factor for mortality globally. Many countries have introduced policies to support the reformulation of foods and to reduce sodium intake, mainly on a voluntary basis, but there are limited data available about the long-term efficiency of such measures. Slovenia implemented salt reduction policies for the period of 2010-2020; these policies also included the voluntary reformulation of foods with the lowering of sodium content. This study's aim was to explore the nationally representative branded food datasets collected in the years 2011, 2015, 2017, and 2020 to investigate the changes in the sodium content in prepacked branded foods. The study was conducted with datasets collected from food labels using standard food monitoring studies and included all the major retailers. Differences in market shares were adjusted by sales weighting, which was conducted using the yearly sales data provided by the major retailers. The food categories with a major contribution to the overall sales of sodium in prepacked branded foods were processed meat and derivatives (19.0%), canned vegetables (7.1%), water (6.7%), bread (7.2%), and cheese (6.3%). Considering the available food products, a notable decreasing sodium content trend was observed in biscuits, breakfast cereals, pizza, and spreads. Year-to-year differences were much less expressed after the correction for market share differences, and neutral trends were most frequently highlighted. This indicates that sodium was less frequently reduced in market-leading products. The study results revealed that very limited progress in sodium food reformulation was achieved in the 10-year period, indicating the need for more efficient policy approaches. The study demonstrated the importance of the systematic monitoring of the food supply for the evaluation of food policies.

Front-of-Package Nutrition Labeling and Its Impact on Food Industry Practices: A Systematic Review of the Evidence

The obesity epidemic has become a major public health concern globally, and the food supply is a significant driver of this trend. Front-of-package (FOP) labels have been implemented in many countries to encourage healthier food choices. This systematic review aimed to examine the effect of FOP label implementation on food manufacturers' practices. A comprehensive search of multiple databases was conducted following PRISMA guidelines, identifying 39 relevant articles from 1990 to 2021. The studies indicated that FOP labels conveying intuitive information influenced product reformulation, whereas those with numerical information without specific guidance had no impact on reducing unhealthy nutrients. The most common outcomes were sodium, sugar, and calorie reduction. Mandatory policies reported higher and more consistent effects on product reformulation compared to voluntary approaches. Voluntary FOP labeling resulted in low uptake and tended to be applied to healthier products. Food manufacturers responded to FOP labeling heterogeneously, depending on the label design and type of enforcement. FOP label implementation can reduce nutrients of concern but food manufacturers behave strategically by labeling healthier choices. This review provides recommendations for maximizing the benefits of using FOP labels to prevent obesity, and findings can inform future public health research and policymaking.

Modelling of salt intake reduction by incorporation of umami substances into Japanese foods: a cross-sectional study

BACKGROUND

Evidence has demonstrated that excess sodium intake is associated with development of several non-communicable diseases. The main source of sodium is salt. Therefore, reducing salt intake in foods is an important global public health effort to achieve sodium reduction and improve health. This study aimed to model salt intake reduction with 'umami' substances among Japanese adults. The umami substances considered in this study include glutamate or monosodium glutamates (MSG), calcium diglutamate (CDG), inosinate, and guanylate.

METHODS

A total of 21,805 participants aged 57.8 years on average from the National Health and Nutrition Survey was used in the analysis. First, we employed a multivariable linear regression approach with overall salt intake (g/day) as a dependent variable, adjusting for food items and other covariates to estimate the contribution of salt intake from each food item that was selected through an extensive literature review. Assuming the participants already consume low-sodium products, we considered three scenarios in which salt intake could be reduced with the additional umami substances up to 30%, 60% and 100%. We estimated the total amount of population-level salt reduction for each scenario by age and gender. Under the 100% scenario, the Japan's achievement rates against the national and global salt intake reduction goals were also calculated.

RESULTS

Without compromising the taste, the 100% or universal incorporation of umami substances into food items reduced the salt intake of Japanese adults by 12.8-22.3% at the population-level average, which is equivalent to 1.27-2.22 g of salt reduction. The universal incorporation of umami substances into food items changed daily mean salt intake of the total population from 9.95 g to 7.73 g: 10.83 g to 8.40 g for men and 9.21 g to 7.17 g for women, respectively. This study suggested that approximately 60% of Japanese adults could achieve the national dietary goal of 8 g/day, while only 7.6% would meet the global recommendation of 5.0 g/day.

CONCLUSIONS

Our study provides essential information on the potential salt reduction with umami substances. The universal incorporation of umami substances into food items would enable the Japanese to achieve the national dietary goal. However, the reduced salt intake level still falls short of the global dietary recommendation.

Monitoring improvements in the nutritional quality of new packaged foods launched between 2016 and 2020

Food and beverage companies reformulate packaged foods and to better align their products with public health policies and evolving consumer needs. The nutritional quality of packaged foodscan be tracked using nutrient profiling methods. The present study compared the nutritional quality of packaged foods launched globally between 2016 and 2018 and those launched in 2018-2020, as reported in the Mintel Global New Products Database. Nutrient profiling analyses showed that the nutrient composition of product categories shifted for almost 40% of newly launched products between 2016-2018 and 2018-2020. For example, pizzas that had been assigned to one nutritionally homogenous category in 2016-2018 separated in two nutritionally distinct subgroups in 2018-2020. The new products that were reduced in protein, saturated fat, and sodium were now nutritionally distinct from the traditional pizza offer. By 2018-2020 "best of category" products were significantly lower in sugar and sodium than before; however, no clear trend was observed for saturated fats, proteins, or fibers. The relative speed of product reformulation was category specific. This analysis of the Mintel Global New Products Database suggests that the WHO nutritional recommendations focusing on sugar and sodium reduction did have a positive impact on the composition of new packaged foods, whether through reformulation of existing products, launches of line extensions or new product development.

Behavioural Nudges, Physico-Chemical Solutions, and Sensory Strategies to Reduce People’s Salt Consumption

This narrative historical review examines the wide range of approaches that has been trialled/suggested in order to reduce the consumption of salt. While sodium is an essential micronutrient, there is widespread evidence that high levels of consumption are leading to various negative health outcomes. This review summarises the evidence relating to the various approaches that have been put forward to date to help reduce salt consumption over the years, while also highlighting a number of important questions that remains for future research. Solutions to reducing salt consumption include everything from the gradual reduction in salt in foods through to the reduction in the number/size of holes in saltshakers (what one might consider a behavioural nudge). Physico-chemical solutions have included salt replacers, such as monosodium glutamate (MSG) through to the asymmetric distribution of salt in processed (e.g., layered) foods. A wide range of sensory approaches to modulating expected and perceived saltiness have also been suggested, including the use of salty aromas, as well as suggesting the use of colour cues, sonic seasoning, and even textural primes. It is currently unclear whether different salty aromas can be combined to increase odour-induced taste enhancement (OITE) effectiveness. In the years ahead, it will be interesting to assess how long such solutions remain effective, as well as whether different solutions can be combined to help reduce salt consumption without having to compromise on taste/flavour

Perceptions and Feasibility of Actions Related to Sodium Reduction among Restaurant Owners and Cooks in Seongnam, South Korea: Comparison According to Stages of Behavioral Change

With the increase in meals eaten outside the home, sodium reduction in restaurant foods is essential for reducing sodium intake. This study aimed to assess the stages of behavioral change for reducing sodium and the differences in perceptions among restaurant staff by stage. Restaurant owners and cooks (n = 313) in Seongnam, South Korea were surveyed on their stage of behavioral change, practices, and perceptive factors related to sodium reduction in restaurant meals using a questionnaire. The proportion of behavioral change by stage was 20.4% in the maintenance and action (MA) stage, 32.3% in the preparation (P) stage, and 47.3% in the pre-preparation (PP) stage, which included contemplation and pre-contemplation stages. The items that represent differences among the groups were recognition of social environment for sodium reduction, practice of weighing condiments and measuring salinity, and feasibility of actions related to low-sodium cooking. Logistic regression analysis was used to estimate odds ratios for practice and perceptive factors by using stage of behavioral change as the independent variable. Factors associated with being in the MA stage were weighing condiments, measuring salinity, and high feasibility of actions related to low-sodium cooking. Recognition of sodium labeling and anticipation of better taste by reducing sodium increased the odds of being in the P stage rather than the PP stage. These results suggest that customized stepwise education and support are needed for the efficacy of restaurant-based sodium reduction programs.

The estimated health impact of sodium reduction through food reformulation in Australia: A modeling study

BACKGROUND

The Australian Government recently established sodium targets for packaged foods to encourage voluntary reformulation to reduce population sodium consumption and related diseases. We modeled the health impact of Australia's sodium reformulation targets and additional likely health gains if more ambitious, yet feasible sodium targets had been adopted instead.

METHODS AND FINDINGS

Using comparative risk assessment models, we estimated the averted deaths, incidence, and disability-adjusted life years (DALYs) from cardiovascular disease (CVD), chronic kidney disease (CKD) and stomach cancer after implementation of (a) Australia's sodium targets (overall and by individual companies); (b) United Kingdom's targets (that covers more product categories); and (c) an optimistic scenario (sales-weighted 25th percentile sodium content for each food category included in the UK program). We used nationally representative data to estimate pre- and post-intervention sodium intake, and other key data sources from the Global Burden of Disease study. Full compliance with the Australian government's sodium targets could prevent approximately 510 deaths/year (95% UI, 335 to 757), corresponding to about 1% of CVD, CKD, and stomach cancer deaths, and prevent some 1,920 (1,274 to 2,600) new cases and 7,240 (5,138 to 10,008) DALYs/year attributable to these diseases. Over half (59%) of deaths prevented is attributed to reformulation by 5 market-dominant companies. Compliance with the UK and optimistic scenario could avert approximately an additional 660 (207 to 1,227) and 1,070 (511 to 1,856) deaths/year, respectively, compared to Australia's targets. The main limitation of this study (like other modeling studies) is that it does not prove that sodium reformulation programs will prevent deaths and disease events; rather, it provides the best quantitative estimates and the corresponding uncertainty of the potential effect of the different programs to guide the design of policies.

CONCLUSIONS

There is significant potential to strengthen Australia's sodium reformulation targets to improve its health impact. Promoting compliance by market-dominant food companies will be critical to achieving the potential health gains.

The Influence of Front-of-Package Nutrition Labeling on Consumer Behavior and Product Reformulation

Countries worldwide have implemented mandatory or voluntary front-of-package nutrition labeling systems. We provide a narrative review of (a) real-world evaluations of front-of-package nutrition labels that analyze objective sales data and (b) studies that objectively assess product reformulation in response to a front-of-package nutrition label implementation. We argue that there is sufficient scientific evidence to recommend that governments implement mandatory front-of-package nutrition labeling systems to improve population health. We also present a conceptual framework to describe front-of-package label influence and provide recommendations for the optimal label design, emphasizing that labeling systems should be highly visible and salient, be simple and easy to understand, leverage automatic associations, and integrate informational and emotional messaging. The existing research suggests that Guideline Daily Amount labels should be avoided and that the Health Star Rating and Nutri-Score systems are promising but that systems with warning labels like the one in Chile are likely to produce the largest public health benefits. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Sodium and Potassium Content of Foods Consumed in an Italian Population and the Impact of Adherence to a Mediterranean Diet on Their Intake

High sodium and low potassium intakes are associated with increased levels of blood pressure and risk of cardiovascular diseases. Assessment of habitual dietary habits are helpful to evaluate their intake and adherence to healthy dietary recommendations. In this study, we determined sodium and potassium food-specific content and intake in a Northern Italy community, focusing on the role and contribution of adherence to Mediterranean diet patterns. We collected a total of 908 food samples and measured sodium and potassium content using inductively coupled plasma mass spectrometry. Using a validated semi-quantitative food frequency questionnaire, we assessed habitual dietary intake of 719 adult individuals of the Emilia-Romagna region. We then estimated sodium and potassium daily intake for each food based on their relative contribution to the overall diet, and their link to Mediterranean diet patterns. The estimated mean sodium intake was 2.15 g/day, while potassium mean intake was 3.37 g/day. The foods contributing most to sodium intake were cereals (33.2%), meat products (24.5%, especially processed meat), and dairy products (13.6%), and for potassium they were meat (17.1%, especially red and white meat), fresh fruits (15.7%), and vegetables (15.1%). Adherence to a Mediterranean diet had little influence on sodium intake, whereas potassium intake was greatly increased in subjects with higher scores, resulting in a lower sodium/potassium ratio. Although we may have underestimated dietary sodium intake by not including discretionary salt use and there may be some degree of exposure misclassification as a result of changes in food sodium content and dietary habits over time, our study provides an overview of the contribution of a wide range of foods to the sodium and potassium intake in a Northern Italy community and of the impact of a Mediterranean diet on intake. The mean sodium intake was above the dietary recommendations for adults of 1.5-2 g/day, whilst potassium intake was only slightly lower than the recommended 3.5 g/day. Our findings suggest that higher adherence to Mediterranean diet patterns has limited effect on restricting sodium intake, but may facilitate a higher potassium intake, thereby aiding the achievement of healthy dietary recommendations.

Growth of Ready Meals in Australian Supermarkets: Nutrient Composition, Price and Serving Size

Pre-prepared, or ready meals (frozen, chilled and shelf-stable) are increasingly available in supermarkets in developed countries. This study aimed to investigate how the range of ready meals in Australian supermarkets has changed from 2014 to 2020, and how products vary by price, serving size, nutrient composition and Health Star Rating. Product information was obtained from the FoodTrack™ packaged food database for the years 2014 to 2019 and from an instore audit of products available in Adelaide, Australia for 2020. There was a 13% annual average increase in the number of ready meals available in supermarkets. Serving size did not change (median 350 g, p-trend = 0.100) and price increased modestly from 2014 to 2020 (median $1.67 to $1.79/100 g, p-trend < 0.001), with chilled ready meals being the most expensive. A modest decrease in sodium density from 2014 to 2020 (median 275 to 240 mg/100 g, p-trend < 0.001) was seen. However, the category has a wide range in Health Star Ratings and nutrient composition, highlighting the importance of appropriate consumer choice to optimise health benefits. With the increasing availability of ready meals, global improvements within this category should be encouraged and consumers guided to choose healthier products.

Strengthening Knowledge to Practice on Effective Salt Reduction Interventions in Low- and Middle-Income Countries

PURPOSE OF REVIEW

The objective of this review was to consolidate available published information on the implementation and evaluation of salt reduction interventions in low- and middle-income countries (LMICs).

RECENT FINDINGS

The Science of Salt database (made up of studies identified in a weekly Medline search) was used to retrieve articles related to the implementation of salt reduction interventions from June 2013 to February 2020. Studies that measured the effects of the interventions in LMICs, based on four outcome measures-salt intake; sodium levels in foods; knowledge, attitudes, and behaviours (KABs) towards salt; and blood pressure-were included. Results were summarised overall and according to subgroups of intervention type, duration, sample size, country's income class, and regional classification. The review identified 32 studies, representing 13 upper middle-income and four lower middle-income countries. The main salt reduction interventions were education, food reformulation, and salt substitution; and many interventions were multi-faceted. More studies reported a positive effect of the interventions (decreased salt intake (12/17); lower sodium levels in foods or compliance with agreed targets (6/6); improved KAB (17/19); and decreased blood pressure (10/14)) than a null effect, and no study reported a negative effect of the intervention. However, many studies were of small scale and targeted specific groups, and none was from low-income countries. Consumer education, food reformulation, and salt substitution, either alone or in combination, were effective in their target populations. Supporting scale-up of salt reduction interventions in LMICs is essential to cover broader populations and to increase their public health impact.

The Equity and Effectiveness of Achieving Canada's Voluntary Sodium Reduction Guidance Targets: A Modelling Study Using the 2015 Canadian Community Health Survey-Nutrition

Background: High sodium intake is a leading modifiable risk factor for cardiovascular diseases. This study estimated full compliance to Canada’s voluntary sodium reduction guidance (SRG) targets on social inequities and population sodium intake. Methods: We conducted a modeling study using n = 19,645, 24 h dietary recalls (Canadians ≥ 2 years) from the 2015 Canadian Community Health Survey—Nutrition (2015 CCHS-N). Multivariable linear regressions were used to estimate mean sodium intake in measured (in the 2015 CCHS-N) and modelled (achieving SRG targets) scenarios across education, income and food security. The percentage of Canadians with sodium intakes above chronic disease risk reduction (CDRR) thresholds was estimated using the US National Cancer Institute (NCI) method. Results: In children aged 2–8, achieving SRG targets reduced mean sodium intake differences between food secure and insecure households from 271 mg/day (95%CI: 75,468) to 83 mg/day (95%CI: −45,212); a finding consistent across education and income. Mean sodium intake inequities between low and high education households were eliminated for females aged 9–18 (96 mg/day, 95%CI: −149,341) and adults aged 19 and older (males: 148 mg/day, 95%CI: −30,327; female: −45 mg/day, 95%CI: −141,51). Despite these declines (after achieving the SRG targets) the majority of Canadians’ are above the CDRR thresholds. Conclusion: Achieving SRG targets would eliminate social inequities in sodium intake and reduce population sodium intake overall; however, additional interventions are required to reach recommended sodium levels.

Population-based Cardiovascular Disease Prevention Measures Aimed at Reducing Salt Intake: Analysis of International Strategies and Prospects for Implementation in the Russian Federation

High salt intake is an important risk factor for cardiovascular diseases (CVD), closely related to the level of blood pressure in the population. The purpose of the review: to study population-based interventions for CVD prevention, aimed at reducing salt intake; to assess the potential for their implementation in the Russian Federation. We presented population-based strategies for dietary salt intake reduction used in different countries. The main components of strategies aimed to correct this risk factor in the Russian Federation were identified. The main components of the population-based approach to reducing salt intake are: determining population salt consumption, identifying sources of salt in the diet, monitoring of salt content in products, engaging with the food industry, consumer awareness campaigns, changes in product labeling, tax measures. An integrated approach to the problem is the most successful. Measures which were highly effective have not yet been fully implemented in the Russian Federation. At the moment, taxation of high-salt foods and tax subsidies for healthy food are not applied. Food manufacturers are not sufficiently involved - there are no legislatively introduced measures to reduce salt through food reformulation. Firstly it has to be applied to diet-forming products that are consumed daily, such as bakery and dairy products, and meat products.

Urinary Sodium Excretion and Blood Pressure Relationship across Methods of Evaluating the Completeness of 24-h Urine Collections

We compared the sodium intake and systolic blood pressure (SBP) relationship from complete 24-h urine samples determined by several methods: self-reported no-missed urine, creatinine index ≥0.7, measured 24-h urine creatinine (mCER) within 25% and 15% of Kawasaki predicted urine creatinine, and sex-specific mCER ranges (mCER 15-25 mg/kg/24-h for men; 10-20 mg/kg/24-h for women). We pooled 10,031 BP and 24-h urine sodium data from 2143 participants. We implemented multilevel linear models to illustrate the shape of the sodium-BP relationship using the restricted cubic spline (RCS) plots, and to assess the difference in mean SBP for a 100 mmol increase in 24-h urine sodium. The RCS plot illustrated an initial steep positive sodium-SBP relationship for all methods, followed by a less steep positive relationship for self-reported no-missed urine, creatinine index ≥0.7, and sex-specific mCER ranges; and a plateaued relationship for the two Kawasaki methods. Each 100 mmol/24-h increase in urinary sodium was associated with 0.64 (95% CI: 0.34, 0.94) mmHg higher SBP for self-reported no-missed urine, 0.68 (95% CI: 0.27, 1.08) mmHg higher SBP for creatinine index ≥0.7, 0.87 (95% CI: 0.07, 1.67) mmHg higher SBP for mCER within 25% Kawasaki predicted urine creatinine, 0.98 (95% CI: -0.07, 2.02) mmHg change in SBP for mCER within 15% Kawasaki predicted urine creatinine, and 1.96 (95% CI: 0.93, 2.99) mmHg higher SBP for sex-specific mCER ranges. Studies examining 24-h urine sodium in relation to health outcomes will have different results based on how urine collections are deemed as complete.

Aortic Aneurysms and Dissections Series: Part II: Dynamic Signaling Responses in Aortic Aneurysms and Dissections

Aortic structure and function are controlled by the coordinated actions of different aortic cells and the extracellular matrix. Several pathways have been identified that control the aortic wall in a cell-type-specific manner and play diverse roles in various phases of aortic injury, repair, and remodeling. This complexity of signaling in the aortic wall poses challenges to the development of therapeutic strategies for treating aortic aneurysms and dissections. Here, in part II of this Recent Highlights series on aortic aneurysms and dissections, we will summarize recent studies published in Arteriosclerosis, Thrombosis, and Vascular Biology that have contributed to our knowledge of the signaling pathway-related mechanisms of aortic aneurysms and dissections.