By Professor Ian Fisk, Professor of Flavour Chemistry, and Deborah Kendale, AgriFood Training Partnership.
The introduction of the ‘Sugar Tax’ on soft drinks may have distracted public attention away from salt, but salt reduction initiatives are still required to reduce the amount consumed in the UK.
Too much salt in the diet leads to high blood pressure, the main cause of strokes and a major contributor to heart disease, the two most common causes of death.
In 2015 Public Health England (PHE) reported that high blood pressure affects 31 per cent of men and 26 per cent of women in England, around 12.5 million people. PHE estimates that reducing the population’s salt intake by just 1g per day would prevent 4147 premature deaths, and would save the NHS £288 million each year.
The World Health Organization (WHO) recommends that adults consume no more than 5g of salt per person per day. This figure is even lower for children. Currently, average daily salt consumption in the UK is substantially higher, at 8.1g – 8.8g per day.
Salt reduction initiatives
Work on salt reduction has been ongoing for a number of years. The United Kingdom was one of the first countries to develop a salt reduction strategy and still leads the way internationally.
The Food Standards Agency (FSA) made salt reduction a public health priority in 2002. Together with Action on Salt, a campaign group supported by 25 scientific experts from UK universities, the FSA set achievable targets for 80 food categories. The food industry was encouraged to agree to them. New and lower targets were set every two years with the aim to reach the UK recommendation of 6g of salt a day by 2015. An average consumption rate across all products that has not yet been achieved.
Success in packaged bread salt reduction
However, some salt reduction initiatives have been very successful according to Action on Salt, particularly the salt content of packaged bread.
Research published in the British Medical Journal (MacGregor et al) showed the results of surveys into the salt content of bread conducted in 2001, 2006 and 2011. Across the 18 bread products surveyed in all three years, there was a significant reduction of 17 per cent.
The study showed that the salt content of bread has been progressively reduced over time, with the number of products meeting the 2012 targets increasing from 28 per cent in 2001 to 71 per cent in 2011. The gradual reduction in salt does not seem to have been noticed by consumers.
However, a 2018 study by World Action on Salt and Health (WASH) on the salt content in bread suggests that UK efforts to reduce salt may have stalled while levels of salt in bread produced in Qatar, China, Costa Rica and South Africa were all below UK levels. World Action on Salt and Health suggested that mandatory reduction targets, such as those put in place by South Africa, may be more effective than voluntary goals.
Ongoing research is being conducted by manufacturers into salt substitutes including low sodium salt.
Traditional sea salt producer, Salt of the Earth, is conducting research into ‘micro-salt’, which is more easily absorbed on the tongue, therefore less is needed to produce the same taste. The company has also developed a product called Mediterranean Umami, which it claims can help reformulaters reduce salt by up to 45 per cent, and sugar in savoury foods by up to 25 per cent.
Baked foods containing ‘hidden salt’
Amongst the FSA-targeted food groups, baked foods have been singled out by consumer groups including Action on Salt because of their high salt content. Biscuits can have rates of more than 1g per 100g of biscuit, while the FSA recommends less than 1g of salt per 100g.
It may be possible to avoid adding salt or salt substitutes if we can identify the role of salt in creating the sensory properties that define a high-quality biscuit.
For example, the perception of sweetness in shortbreads is influenced by the level of salt in the matrix - even if the quantity of salt in sweet food is below the consumer's sensory threshold. This ‘hidden salt’ doesn’t necessarily lead to a perception of saltiness.
The Food Flavour Research Group
In the Food Flavour research group at the University of Nottingham, a number of research projects are contributing to a better understanding of the role of salt on the overall flavour of baked foods.
Charfedinne Ayed (a research fellow in the Food Flavour group) is studying the impact of hidden salt on the generation of flavour during baking and the subsequent quality aspects of foods.
Katherine Hurst, a PhD student in the Food Flavour group, is working to develop an understanding of the impact of salt inclusion on the breakdown in mouth - which directly affects eating quality.
The Food Flavour group at the University of Nottingham is a leading European flavour research centre. It offers direct support to food companies trying to reduce salt in processed foods and training courses in food flavour through the AFTP. The group is continuously developing new techniques to identify the impact of salt reduction and food production methods that lower the salt content in foods.