EU Science Hub

Dietary Salt/ Sodium

Table of Contents

1. Defining dietary salt and sodium
2. Dietary sources of salt
3. Labelling salt in the EU
4. Salt intake: effects on health
5.Recommended intake of salt
6.Salt intake across European countries
7.Disease burden related to salt intake
8.Policy recommendations on salt intake
9.Implemented policies addressing salt

1. Defining dietary salt and sodium

Salt or sodium chloride (NaCl) is a crystalline compound consisting of sodium (Na) and chloride (Cl). One gram of salt contains about 0.4 g of sodium and 0.6 g of chloride. Likewise, in the context of salt content or intake, one gram of sodium equals approximately 2.5 g salt (EU 2011).

Salt used as an ingredient for food, either directly sold to consumers or used for food manufacturing, shall not be less than 97% of sodium chloride (FAO/WHO 2006), on a dry matter basis, exclusive of additives. Depending on the origin and the method of production of the salt (obtained from the sea, from underground rock salt deposits or from natural brine), it may contain varying traces of other minerals. For public health reasons salt may also be fortified e.g. with iodine, iron or fluoride (FAO/WHO 2006).

The words salt and sodium are often used interchangeably (WHO 2016). Most sodium is consumed in the form of sodium chloride and the public understands the term salt better than sodium. EU Regulation 1169/2011 (EU 2011) on food information to consumers requires the declaration of the salt content calculated as salt equivalents from the sodium content of a product (see Paragraph 3). Also, the High Level Group on nutrition and physical activity experts refer to salt and not sodium (EC 2012b). For the purposes of this brief, both terms will be used according to the the context and the source used.

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2. Dietary sources of sodium

Salt (sodium chloride) is commonly used as a food ingredient or condiment. The main purposes for the usage of salt are for enhancing taste and preserving the product (EFSA 2005). At the EU level, it is estimated that 95% of sodium is consumed in the form of salt (EC 2012b).

Most of the sodium intake (70-75%) comes from processed foods, while 10-15% comes from naturally occurring sodium in unprocessed foods and 10-15% from discretionary sodium added during cooking or eating (EFSA 2006). Besides salt, other examples of sodium containing compounds added to foods are sodium nitrate, monosodium glutamate and sodium phosphate.

The quantity of intrinsically occurring sodium in unprocessed foods is very low, compared to processed foods (WHO 2012, Kloss 2017); Table 1 gives examples of the sodium content of the same food in unprocessed and processed states.

The main food groups responsible for salt intake in Europe are bread and bakery products, cereal products, meat and meat products as well as cheese and dairy products. Other important groups are ready meals and soups (EC 2012b, Kloss 2017). Bread, cereals and bakery products are the most important sources of salt in many national diets, bread alone contributing to around 20% or more of the total salt intake. In the US, most (71%) of the salt intake comes from sodium added to foods consumed outside home (Harnack 2017). According to USDA Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC 2015), mixed dishes, especially burgers and sandwiches, are the main contributors to intake of salt in American diets.

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3. Labelling salt in the EU

In the EU, Regulation (EU) 1169/2011 (EU 2011) on food information to consumers requires the mandatory nutrition declaration of the salt content in prepacked foods. To ensure that the final customer easily understands the labelling, it is appropriate to use 'the term salt instead of the corresponding term of the nutrient sodium'. Therein, 'salt means the salt equivalent content calculated using the formula: salt = sodium × 2,5'. The unit of measurement to be used is g per 100 g of product. The daily reference intake for salt is 6 g for adults, and the salt content can be expressed as a percentage of the reference intake per 100 g or per 100 ml.

Under Regulation (EU) 1924/2006 (EC 2006) on nutrition and health claims made on foods, the following salt-related nutrition claims are permitted:

  • Low sodium/salt claims, 'may only be made where the product contains no more than 0.12 g of sodium, or the equivalent value for salt, per 100 g or per 100 ml. For waters, other than natural mineral waters falling within the scope of Directive 80/777/EEC, this value should not exceed 2 mg of sodium per 100 ml.'
  • Very low sodium/salt claims, 'may only be made where the product contains no more than 0.04 g of sodium, or the equivalent value for salt, per 100 g or per 100 ml. This claim shall not be used for natural mineral waters and other waters.'
  • Sodium-free or salt-free claims, 'may only be made where the product contains no more than 0.005 g of sodium, or the equivalent value for salt, per 100 g.'
  • Reduced salt claims, 'may only be made where the reduction in sodium is at least 25 % compared to a similar product.'
  • No added sodium/salt (EC 2012a) claims, 'may only be made where the product does not contain any added sodium/salt or any other ingredient containing added sodium/salt and the product contains no more than 0.12 g sodium, or the equivalent value for salt, per 100 g or 100 ml.'
  • 'Where appropriate, a statement indicating that the salt content is exclusively due to the presence of naturally occurring sodium may appear in close proximity to the nutrition declaration' (EU 2011).

If food is at least as low in salt as referred to in the claim low sodium/salt presented above, the following health claim is permitted:

  • 'Reducing consumption of sodium contributes to the maintenance of normal blood pressure' (EU 2012).

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4. Salt intake: effects on health

Sodium is an essential nutrient and is necessary for normal cell function and for neurotransmission (WHO 2012). From a public health perspective, a number of national and international institutions have examined the impact of salt intake on health, focusing on effects on blood pressure, cardiovascular disease, stomach cancer and renal functions. The statements or opinions of these institutions are shown in Table 2.

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5. Recommended intake of salt

International health related organisations have issued recommendations to limit salt intake to less than 5 or 6 g per day (see Table 3A). In the EU, most national recommendations that quantify salt intake recommend the same. The use of iodized salt is endorsed by many countries in their recommendations (WHO 2003), in order to tackle iodine deficiency, which is still a concern in Europe (WHO 2009). Although fluoride deficiency is not an issue in Europe, fluoridated salt is used, among other dietary sources of fluoride, as a preventive tool against dental caries, and therefore the consumption of fluoridated salt is recommended in many countries and relevant products are available in several EU Member States (SCHER 2010).

The minimum physiological need for sodium is estimated to be 200-500 mg/day (about 0.5-1.25 g of salt per day) (WHO 2012). Adequate intakes of sodium in adults have been estimated mostly around 1.5 g/day (corresponding to 3.8 g salt/day).

Recommendations are lower for children as described in Table 3b. The WHO Global Action Plan for the Prevention and Control of Noncommunicable Diseases 2013-2020 (WHO 2013) set nine global targets, one of which is 'a 30 % relative reduction in mean population intake of salt/sodium by 2025'. This is considered to be necessary for reaching the overall target of reducing premature mortality from non-communicable diseases (NCDs) by 25 % (WHO 2016).

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6. Salt intake across European countries

The European Commission's Survey on Members States' Implementation of the EU Salt Reduction Framework (EC 2012b) includes Member States (MS) data on population salt intake from the 1990s to 2012. The data from the survey and additional data from more recent studies are presented in Table 4a and 4b. Comparability between MS is limited due to different age ranges covered, different data collection methods (the 24-hour urinary measurement is considered to be the most accurate method) and the difficulties in assessing discretionary salt.

Based on the data, salt intake is usually higher in men than in women. Mean daily intakes of salt around the world far exceed the minimum physiological need. In the majority of European countries, the range of intake is 7 to 12 grams of salt per day (EC 2012b).

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7. Disease burden related to salt intake

The Global Burden of Disease (GBD) study defines a diet being high in sodium when it results in an average 24-hour urinary sodium excretion that is greater than 3 grams per day (GBD study 2017). In 2017, the GBD study estimated that in 28 EU member states a diet high in sodium was accountable for more than 182,000 deaths and 2,950,000 disability adjusted life years (DALYs), both mainly associated with cardiovascular diseases, stomach cancer and chronic kidney disease (GBD tool).

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Table 5 presents a number of policy recommendations to reduce salt intake. These measures may be combined, as according to WHO (WHO 2016), a combination of different policies appears to reduce salt consumption effectively. For evaluating the effectiveness of salt reduction programs, measuring and monitoring population salt intake, salt content of foods and a population's attitudes on salt is important.

Population-wide salt reduction is considered one of the most cost-effective strategies to address high blood pressure as a public health problem and to prevent NCDs (WHO 2016). Even modest reduction in blood pressure would have wide public health benefits, reductions in mortality and savings in health-care costs (WHO 2012). Considering the high prevalence of suboptimal blood pressure, many adverse effects on health are seen in individuals who are not hypertensive but in-between the optimal and hypertensive range (WHO 2003).

It has also been noted that where relevant, successful salt reduction programmes should be integrated with iodine deficiency elimination programmes to ensure that optimal population intake of iodine is achieved even with reduced salt intakes (WHO 2016), and that salt reduction and salt iodization are compatible6. In addition, WHO notes that salt intake reduction recommendations should be seen in conjunction with potassium intake recommendations, and if both sodium and potassium are consumed at recommended levels, their ratio would be 1, which is considered beneficial for health (WHO 2012).

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9. Implemented policies addressing salt

Similar to policy recommendations, most of the implemented policy approaches can be broadly categorised into those that aim to provide information, make the healthy option available, or provide financial (dis)incentives related to salt consumption. Table 6 provides examples of different measures to address salt consumption that governments around the world have adopted. These range from legally binding obligations, e.g. limit of salt content in bread, to voluntary actions involving co-operation with the food industry, e.g. voluntary reformulation pledge of the EU Platform for Action on Diet, Physical Activity and Health.

The number of countries with salt reduction strategies has been increasing. In 2014, 75 countries worldwide had a national salt reduction strategy (Trieu 2015). Most countries implement more than one type of measure, shifting from voluntary approaches towards legislative initiatives (Trieu 2015).

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References