A high dietary sodium intake is closely related to elevated blood pressure (BP), which is a major risk factor for the development of cardiovascular disease (CVD). Elevated BP causes almost 13 percent of all deaths worldwide, and in 2008, the global overall prevalence of elevated blood pressure in adults was around 40 percent.
However, the majority of CVD deaths attributable to BP occur at levels where drug therapy is not indicated. Achieving a small downward shift in the distribution of BP in the whole population would achieve a surprisingly large CVD reduction.
Extensive evidence shows a consistently direct relationship between BP and salt/sodium intake. In line with this evidence, several countries and health organisations have developed sodium reduction recommendations. They have also provided evidence-based appraisals of how this might be achieved in specific settings.
The current targets of daily salt intake set by the World Health Organization (WHO) are five g/day or less. Currently, daily salt intake in most countries varies between nine to 12 g, which is well above WHO’s recommendations and represents a major public health concern.
It has been reported that a 4.6 g reduction in daily salt intake decreases BP by about 5.0/2.7 mmHg in hypertensive individuals and by 2.0/1.0 mmHg in normotensive people and that a five g higher salt intake is associated with a 17 percent greater risk of total CVD and a 23 percent greater risk of stroke.
A reduction in population sodium intake may be achieved through a variety of approaches, such as health promotion and awareness campaigns, voluntary collaboration with food producers, the use of salt substitutes in households and in food manufacturing and also by regulatory means, including regulations on the use of nutrition and health claims.
Public Perception & Awareness
Rahim Packir Saibo, Leeds, England
Barriers to progress in reducing sodium intake in the general population were investigated in a recent international study, revealing that while sodium reduction is seen as important, over one-third of participants were not interested in salt/sodium reduction and the majority were unaware of the recommendations.
Key strategies to reduce sodium intake should therefore focus on both lowering the availability of sodium in foods and raising consumer awareness about the importance of cutting sodium intake. However, it is very challenging to reduce sodium in food due to sodium’s specific functionality, in terms of the flavour and the associated palatability of foods (the increase in saltiness, reduction of bitterness, enhancement of sweetness and other congruent flavours).
A gradual reduction of sodium while maintaining palatability is therefore one of the best strategies. For example, it has been shown that such an approach enables at least a one-quarter reduction of the sodium content of bread, while maintaining consumer acceptance.
In the European Union (EU), the use of nutrition and health claims has been harmonised since 2006, enabling the promotion of food with a variety of statements on food labelling and advertising, including a series of sodium-related nutrition and health claims.
To assess the efficiency of the above-mentioned approaches, robust and reliable evaluation methods are needed. While average sodium excretion in 24 hour urine is recognised as the gold standard marker for measuring sodium intake in the population, this method cannot identify food sources of sodium. Therefore, different methods are used to assess population exposure and sodium availability in foods on the market.
Many processed foods have a relatively high sodium content and are recognised as the main contributors to population dietary sodium intake in both adults and children. The sodium content of processed foods varies among food categories.
The biggest food sources of sodium, besides plain salt used as a condiment, include processed meat, bread and bakery products, cheese and ready prepared meals. Sodium intake reduction can be achieved by gradually reducing the sodium content of certain foods, bringing many beneficial effects for public health.
Sodium Initiatives & Campaigns
See-ming Lee, Hong Kong, China
There have been several successful initiatives and public health campaigns to reduce the sodium content of processed foods in recent years, but more can still be done in this area. The consistent monitoring of sodium levels in processed foods over time is critical for assessing voluntary collaborations with the food industry and the need for further public health activities.
While in many countries sodium-reduction targets have been set for a large number of processed food categories, efficient assessment and monitoring are essential for evaluating related progress. Targeting sodium reduction in a small number of food categories and focusing on products sold in the highest volumes could lead to large decreases in sodium available for consumption and, therefore, to gains in public health.
A comparison of the average sodium content of specific food (sub)categories with (SCS) and without the use of weighting by sales (SCA) provides very useful information on the sodium content of the foods of market leaders, in comparison to the average sodium content in a particular food category.
In a study conducted in Slovenian, it was observed that in most food categories, SCS levels are lower than SCA levels, suggesting that market leaders in the Slovenian market have lower sodium contents than the category average.
One reason for such an observation could lie in consumers’ awareness of health risks related to high salt/sodium intake, but in general, this should be attributed to a combination of different factors, including price, brand, taste and texture expectations and consumers’ experiences with a particular food product.
The highest sodium content was found in processed meat products (915 mg/100 g), particularly in dry cured meat (1,467 mg/100 g). The results were generally in line with the average sodium content of foods in Slovenia determined in an earlier study using the Household Budget Survey and labelling information of prepacked foods and a combination of information from food composition databases and laboratory analyses of products available in households, except for dry cured meat, where 18 percent lower average sodium levels were observed.
Steven Depolo, Grand Rapids, US
Nutrition declarations are currently only compulsory in the EU for foods labelled with nutrition and/or health claims, and the proportion of foods with labelled nutrition information varies significantly between different food categories and countries.
Interestingly, among all EU countries, the smallest proportion of foods with a nutrition declaration was found in Slovenia. By the end of 2016, the inclusion of salt content on labelling will become mandatory for all processed prepacked foods in the EU.
High sodium levels were also observed in ready meals, particularly in frozen pizza. The most extreme differences between sales-weighted and unweighted sodium content levels were observed for butter and frozen savoury dishes.
Food labelling presents one of the strategies for improving consumers’ awareness about sodium content in foods. However, the possibilities for food producers to communicate the reduced sodium content of foods are very limited. Currently, five different sodium-related nutrition claims may be used in the EU: (1) low sodium; (2) very low sodium; (3) sodium-free; (4) no added sodium; and a comparative claim, (5) reduced sodium; together with other statements with the same meaning for the consumer.
In addition, foods with a low or reduced content of sodium can be labelled with the health claim ‘reducing consumption of sodium contributes to the maintenance of normal blood pressure.’
Use of sodium-related nutrition claims within food categories known to be major contributors to dietary sodium intake was very rare. For example, only five products in bread and similar products and two products within processed meats were labelled with a sodium-related nutrition claim, while no such claims were found among cheeses.
Evaluation of the sodium content of all available products within those categories revealed that the majority of products do not comply with the strict criteria for using the nutrition claim of low sodium (less than 0.12 g of sodium per 100 g/mL).
In fact, no products within bread, processed meats and cheese were eligible for such a claim. Therefore, the only possibility for informing consumers about lowering the sodium content was to use a comparative claim on reduced sodium, where at least a 25 percent reduction of sodium should be assured.
Only four products were labelled with such a claim. This indicates that, in most cases, food producers that are gradually reducing the sodium content of their foods are unable to communicate this to consumers.
A major strength of the study was its employment of academic-commercial collaboration, which enabled cost-effective use of sales data to assess average sodium contents in various food categories.
Food retailers operate with detailed data on sales of any food products available, and the use of such data does not incur any additional cost. Such an approach facilitates the assessment of sodium availability in foods on the market in unprecedented dimensions, particularly if the partnership combines a series of different retailers accounting for the majority of market share, as was the case in this study.
Compared to methods where food recalls or diaries are used, the use of 12-month sales data allows more precise estimates of the average sodium content in specific food categories and efficient monitoring of changes in the food supply.
Since no additional efforts (other than purchasing) are needed from consumers, there is also no risk of under-reporting purchases of specific foods. Further, considering that the majority of the market is included, the habits of consumers of all demographic backgrounds are well represented.
A comprehensive database on the composition of foods available on the market is needed to perform such studies. To enable the food supply to be monitored over time, such a database should be regularly updated and be available for use without restrictions.
An international collaborative project is underway within the Global Food Monitoring Group, in which the nutritional composition of processed foods is surveyed using standardised methodology on a yearly basis in a number of countries.
Such an approach enables efficient monitoring of the food supply to support governments, industry and communities to develop strategies to fight against food-related non-communicable diseases, particularly when connected with food sales/consumption data.
Given that food labelling data are mostly in line with the actual sodium content of the product, such data represent valid and easily accessible information for further estimations.
A combination of 12-month food sales data provided by food retailers covering the majority of the national market and a comprehensive food composition database compiled using food labelling data represent a robust and cost-effective approach to assess the sales-weighted average sodium content of prepacked foods. Such an approach is a useful tool for monitoring the sodium content of processed foods on the market and shifts in purchasing behaviour.