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What is Salt? What is Sodium?
Salt, or sodium chloride, is a naturally occurring mineral that can be found in seawater, in underground salt deposits and on the surface of the earth. It is made up of 40% sodium and 60% chlorine. Salt and sodium are not the same. Sodium is present in salt, but also in many other food ingredients. It occurs naturally in all plant and animal foods.
Historically salt has always been used as a valuable food ingredient to flavour or to preserve/cure foodstuffs. It is a seasoning found in most people’s kitchen and is indispensable in the preparation of many foods which have distinctive flavours and textures.[1]
Of the overall dietary intake of sodium it is estimated that about 10% comes from sodium naturally present in food, around 15% is added during cooking or at the table, and the rest comes from the many different processed foods available. Due to its presence in different foods, and because of its particular role in human health, food labels often contain information about sodium rather than salt.
Sodium and Health
Sodium is an essential mineral required by the body and has important physiological functions. For example, it helps to regulate fluid and mineral balance in and out of cells, and to maintain normal blood pressure. It also has a role in transmitting nerve impulses that control the body.[2] We need sodium for a healthy body; but too much of it can have an adverse effect on some people.
For adults, EURODIET[3] recommends no more than 6g of salt per day (about one rounded teaspoonful).
For most people, any excess sodium passes straight through the body; however in some salt-sensitive people with impaired kidney function (about one in five) it can increase blood pressure.[4]
Reducing the amount of salt in the diet of those who are sensitive to salt may reduce the risk of high blood pressure, yet a general relationship for the majority of the population remains to be established. Research projects, such as the Rotterdam Study,[5] could only observe a positive association between sodium intake and blood pressure for people who were obese.
Other factors such as stress, excess alcohol, excess weight, smoking or high cholesterol values are likely to be more important causes of high blood pressure.[6] The European Food and Information Council (EUFIC) states: “Obesity, low levels of physical activity and low intakes of potassium have greater effects on blood pressure than high sodium intakes.”
Salt and Savoury Snacks
Salt is added to foods for different reasons: as a preservative, to enhance the flavour, and to improve texture.
In savoury snacks salt is normally applied as part of the seasoning where its presence helps to enhance and compliment the other flavour components present.
Salt is also added to the base recipe of some extruded snacks where it has a key role in regulating product expansion and developing the desired texture and mouthfeel.
A very wide range of savoury snack products are available including those with ‘no salt’ and those with ‘reduced levels’ of salt present. Typically an average 25g serving of ready salted potato crisps will contain around 1/3 g of salt (= 0.15g of sodium), which would contribute about 5% to the daily recommended intake of 6g of salt.
Savoury snacks make only a low level contribution to the overall dietary intake of salt and sodium. In the UK, by far the biggest market in Europe, savoury snacks contribute less than 2% of the overall dietary intake - more than 98% coming from other food products.
Salt Reformulation
Savoury snack manufacturers have responded quickly to changing consumer preferences with respect to salt and many ranges of lower-salt and no-salt products are now available. These allow consumers to
make the choices best suited to their individual lifestyles.
The savoury snacks industry as part of the food industry is working together with public authorities, the European Commission and WHO in order to explore adverse health effects of salt intake, such as high blood pressure. This should include a review of the evidence linking dietary salt to blood pressure.
When looking at product reformulation to reduce salt levels, technological limits to the reduction of sodium must be taken into account. For instance, a certain level of salt is essential for the base recipe of some extruded snacks where it helps regulate product expansion.
Reformulated products must also meet consumer expectations if they are to be accepted. As the individual’s taste however adapts only slowly to lower salt contents, reductions can only take place gradually over a period of time.
References
[1] A Grain of Salt and a Grain of Sense?, in: EUFIC Food Today No 25 (2004)
[2] A Grain of Salt and a Grain of Sense?, in: EUFIC Food Today No 25 (2004)
[3] EURODIET Core Report, Nutrition & Diet for Healthy Lifestyles in Europe, 2000
[4] Salt Sensitivity, a determinant of blood pressure, cardiovascular diseases and survivial. Franco V, Oaril S. in: JACN 2006; 25 (3): p. 247-255
[5] J. M. Geleijnse, J. Witteman, T. Stijnen, M. Kloos, A. Hofman en D. Grobbee. Sodium and potassium
intake and risk of cardiovascular events and all-cause mortality: the Rotterdam Study, in Eur J
Epidemiol, DOI 10.1007/s10654-007-9186-2
[6] A Grain of Salt and a Grain of Sense?, in: EUFIC Food Today No 25 (2004).
Other recent publications underline these results: Fabian Waechter, Österreichische Ärztezeitung, v.10.10.2005 – Nr.19, Wien ; G.R. Kaufmann, A. Zeller. Salz, Hypertonie und kardiovaskuläres Risiko, Therapeutische Umschau Band 62, 2005 – Heft 9, Bern ; K.-L. Resch. Kochsalz und Bluthochdruck: Abschied von einem lieb gewonnenen Feindbild?, Journal Pharmakologie und Therapie, 1/2005 – 14. Jahrgang, Nürnberg ; David Feder R.D. Bad Science slams Salt, Food Processing, June 2005. ; John Luik. A Grain of Salt, Tech Central Station, 11/15/2005
Salt, potassium and the control of blood pressure, in: EUFIC Food Today 12/2006
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