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June 2009

Science in SocietyThe Salt debate

Introduction

The nation is constantly bombarded with health messages concerning desirable components of a healthy diet, of which salt tends to be viewed negatively. This document gathers conflicting positive and negative information surrounding salt; presenting it in an impartial format to provide a holistic view of all sides of the Salt debate. The conclusion of most authorities is that adults should try to reduce the salt content of their diets to 6g/ day.

What is Salt?

Salt, or sodium chloride (NaCl), separates into its two constituent ions, sodium (Na+) and chloride (Cl-) when dissolved in water. In Britain rock salt is mined in Cheshire, Teeside and Northern Ireland for use on the roads during particularly icy weather; it occurs naturally in sea water. Salt has an extensive history involving ritual offerings for eradicating evil spirits, as well as a variety of uses in the development of products including pottery, textiles and as a method of food preservation. Historically it was traded weight for weight with gold, with the word ‘salary’ being derived from the Latin word salarius, meaning salt money.

Sodium is required in many biochemical pathways and is vital for nerve transmission, the passage of nutrients as well as maintenance of blood pressure. Chloride is concerned with the maintenance of blood volume, blood pressure and the pH of body fluids. Salt is a highly valued compound which is vital for hydration, it is a major component of Oral Rehydration Therapies and is used in saline solutions to clean wounds.

Sources of salt in our diet

Approximately 10% of salt in the diet occurs naturally in foods. In addition, a large proportion of salt in the western diet comes from foods which have undergone processing (75%). The salt is used as a preservative as well as a flavour enhancer. The disadvantage of this additional salt is that it is not always detectable upon consumption. Many foods which are not perceived as salty may be main contributors to the daily average intake. Foods high in salt include salted meats, hard cheese, ready meals, cereals, sauces, soups and tinned foods. These foods may not be perceived as salty as the salt is combined within the product. This makes detection by the taste receptors far more challenging, compared to the external salt detected on pre-salted food items such as potato snacks.

The National Diet and Nutrition Survey (2004) reported that 73% of those interviewed added salt to their meals during cooking, with men being more likely to add salt than women.

‘Discretionary salt,’ added onto food at the table, increases salt intake by an estimated 10-20%.  The levels of discretionary salt are primarily added out of habit; experiments involving an increase in the diameter of holes on salt pots, meant that more salt was unintentionally added to the same foods, by the same people, on different occasions.  

Minor contributors to sodium intake include monosodium glutamate, sodium bicarbonate, sodium fluoride, sodium nitrite and a number of other additives.

Why do we need salt?

 Sodium is vital for our health. The body of an adult man (weighing 70 kilos or 11 stone) contains about 92g sodium. Sodium and potassium are both required for the maintenance of extracellular fluid volume (which influences blood pressure), for the generation and transmission of electrical impulses in nerves and muscle, and for the uptake of certain nutrients from the small intestine. The chloride ion is also needed for the production of digestive acids in the stomach. Most healthy people metabolise sodium normally and excrete any excess consumed.

Sodium excretion is usually associated with dehydration, or when people are not acclimatised to their environment. Active workers can lose up to 8 litres of sweat a day, and since sweat contains 0.5-1.9g sodium/litre, failure to replenish the salt in the body can have harmful effects. However, an excessively high sodium intake can also cause problems. Infants are particularly prone to sodium toxicity, which can be detected in some babies after drinking undiluted cows milk, or if infant formula milk has been given at too high a concentration.

How much do we need?

Healthy adults maintain a sodium balance on intakes as low as 69-460mg/day. Low intakes require maximal adaption to conserve sodium, to allow for changes in physical activity and climate. The Scientific Committee for Food (SCF) suggested a lower limit for sodium intake at 575mg/day and an upper limit of 3.5g/day as far ago as their 1993 report. This means that our salt intake should be between 1.5 and 9g/ day. By contrast, the UK Dietary Reference Values for sodium were set in 1991 “on the basis of risks and benefits which might practically be expected to occur given the prevailing socio-cultural environment.” The current Reference Nutrient Intake (RNI) for men and women is 1.6g sodium per day (4.2g salt). The current Lower Reference Nutrient Intake for infants up to 6 months (140mg/day sodium) was based on the sodium content of breast milk, calculated from daily losses in faeces, skin and urine and with an allowance for the sodium needed in the increasing volume of body fluid.  

Dietary Reference Values (DRV) for potassium were set in 1991 “such that excess sodium can be excreted.” The RNI for adults is now 3.5g/day potassium. As long as renal function is normal it is almost impossible to induce potassium excess, although intakes of about 18g/day have been shown to cause temporary increases in blood potassium, and customary intakes should not exceed this level. Chloride is the major element which balances sodium and potassium in cells. In the guide to DRVs, it states that chloride DRVs can be derived from sodium DRVs by multiplying by 1.54 to allow for different molecular weights.

How much do we eat?

Surveys measuring urinary sodium excretion (a proxy measure of intake) in the 2004 NDNS data, suggested that in the UK the average total salt intake was about 11.0g/d for men compared with 8.1g/d for women. This brought the national average salt intake to 9.5g, a 0.5g increase on previous 1986/7 data. However, the Food Standards Agency has since published data suggesting that their reduction strategies have lowered this national average value to 8.6g per day (2008).

Salt in food processing and manufacture

Salt is added to foods to preserve it, and to add flavour and texture. It is widely used in dairy products, meat and fish products, canned vegetables, some cereals, bakery products, confectionary, pickles and sauces.

One of the earliest uses of salt was as a preservative, as it reduces water activity which inhibits or slows the growth of food poisoning or spoilage microorganisms. Salt is added in cheese making to retard the growth of harmful microorganisms, while allowing the growth of the salt-tolerant moulds responsible for the fermentation process. In addition the salt helps to develop the flavour and texture of the cheese. Most meat products contain salt, added both as a flavouring agent and to inhibit bacterial growth. The combination of NaCl and nitrite, used in curing, ensures that bacon and ham have a longer shelf life, and canned ‘NaCl-plus–nitrite’ cured meat products can be made shelf stable by a heat process which is much less intense than that required for canned uncured meats or meat products. In the absence of nitrite, salt has a only a limited preservative effect and is used mainly for the purpose of adding flavour and texture, such as in mechanically-reconstituted meat products. Sodium is also added to some meat and meat products as sodium polyphosphate, to influence water-holding and give the products a moist texture. Salt also plays a part in fat emulsification, thus diminishing the loss of fat and water during cooking in products such as sausages.

Canning and brining processes are used to improve the flavour of canned vegetables, though the brines are normally discarded in the home before reheating. Pickles and relishes contain appreciable amounts of salt (but are not normally eaten in large quantities).

Yellow fats, such as margarine, fat spreads and butter, may also contain a considerable amount of salt (1.5-3.5g/100g) primarily added as flavouring.

An average portion of bread contains about 0.5g of salt (0.2g sodium). Without salt or additional sodium derived from baking soda and other leavening agents, bread and similar products are described as tasting “insipid.” As well as affecting the flavour profile of bread, salt also influences starch properties, dough rheology, baking properties and bread quality characteristics. It reduces crumb stickiness in dough, and bread baked without salt has a coarse, unacceptable crumb structure. However, this effect appears to be related in part to ionic strength rather than the presence of sodium ions particularly, so that up to 40% replacement of sodium chloride with potassium, calcium or magnesium salts has been reported to have no adverse effects on baking performance, provided optimum mixing times are used. In addition, the flavour of test breads was apparently poor. By contrast, the need for salt is greatly reduced in rye breads and sour dough breads, and good sensory characteristics have been obtained with 0.75% NaCl.

Baking trials carried out by Dalgety, in which sodium chloride was replaced by potassium or calcium chloride at levels of 0.5%, 1.0% and 2%, resulted in bitter tasting loaves - the higher levels, particularly of calcium - were described as very unpleasant. The bitterness was persistent and was still clearly detectable when mixtures of sodium and potassium were used (e.g. 40% Na, 60% K) as in Lo-Salt™.

In breakfast cereals, salt has a key flavour-blending role, added at about 1.25-1.75% by weight. Nevertheless there are some exceptions, such as shredded wheat products, which have sodium levels close to zero. During processing, hydroscopic ingredients such as salt and sugar compete with starch for moisture, reducing the effective concentration of water available for gelatinisation and requiring higher temperatures and longer times to produce the same results – a dry, puffed product.

Salt is added to a variety of other foods as a flavouring and flavour enhancing agent. In particular, savoury biscuits and crackers, crisps and snacks, bottled sauces, canned and packet soups traditionally have high salt contents, but unsalted versions, particularly of dried items are now more widely available.

A 2010 systematic survey of the salt levels in processed foods was carried out by the George Institute for International Health in Sydney, Australia.  It found that whilst many products (particularly breads, processed meats, and sauces) have high salt levels, some comparable products did not.  This suggests that reducing salt concentrations by reformulating the products is highly feasible for many processed foods.

Why is there a debate about salt intake?

Despite the association between high salt ingestion and diseases such as osteoporosis, gastric cancer and hypertension, a deficiency in salt may also be problematic as sodium chloride is involved in many reactions and functions with in the body; such as hormones, blood pressure, the nervous system and metabolism. The salt debate is fuelled due to conflicting evidence surrounding the effectiveness of reducing dietary sodium in normally healthy individuals.

The hypertension link

Hypertension is a concern as it is a major risk factor for heart disease, strokes and kidney failure. It is common for systolic blood pressure (the pressure in the arteries during heart contraction) to increase from 115 mm Hg at the age of 15 to approximately 145 mm Hg at the age of 65. Although age related hypertension is perceived as being normal, investigations surrounding many African populations showed that blood pressure elevations only occurred when there was movement from traditional society to western civilisation. This suggests that a factor of our lifestyle is linked to hypertension. Hypertension is a multi-factorial illness; sufferers may have a genetic predisposition or the problem may be exacerbated by a poor diet, stress, lack of exercise and increasing age.

 A decrease in potassium levels in the blood is also associated with elevated blood pressure. The British Nutrition Foundation suggest that a positive potassium to sodium ratio is advantageous, hence an even larger emphasis should be placed upon increasing fruit and vegetable intake.

Electrolyte imbalances caused by inefficient sodium excretion by the kidneys, may cause excess fluid retention; the prevention of fluid elimination may further contribute to increased blood volume. In time this may enhance blood vessel contraction, promoting hypertension. The kidneys are then subject to an increased strain which may increase the rate of deterioration in renal disease, possibly leading to increased proteinuria. Reductions in salt intake result in reduced protein in the urine; the resulting lower blood pressure achieved by low sodium diets also reduces the risk of cardiovascular disease.

The gastric cancer link

Excess salt acts as an irritant to the stomach lining, increasing the risk of Helicobacter pylori infections. In addition it may also act as a carcinogen, increasing the risk of gastric cancer. Gastric cancer has a particularly high prevalence in Japan due to the nature of their highly salted food processing techniques. A review by Tsugane (2004) documented that the average sodium excretion over a 24hour period is positively correlated with the increased gastric cancer link.

The osteoporosis link

A high salt intake is positively related to calcium excretion. The National Diet and Nutrition Survey data found that young people are deficient in calcium and potassium; this, combined with an elevated sodium intake, prevents them from reaching their peak bone mass and predisposes them to osteoporosis in later life. Higher salt intake is linked to renal stones as well as to osteoporosis. Studies on post menopausal women have found that the loss of hip bone density was closely correlated with sodium excretion.

The World Action on Salt campaign states that halving the salt intake from 10g -5g may have the same effects on calcium preservation of hip bone density as increasing dietary calcium by 1000mg.

Obesity

Salt has been linked as a factor in obesity, primarily due to an elevated consumption of soft sugary drinks to combat thirst produced by high salt diets, leading to higher energy intakes. This increase has not been followed by rising energy expenditure. Some predictions suggest that a 25% decrease in the sales of soft drinks would lead to a $16 billion loss of sales in the United States; data such as these may explain why some companies are slow to comply with salt reduction initiatives.

The different viewpoints

The view of medical practitioners/ nutritionists

The difference in opinion amongst medical experts regarding the role of sodium, potassium, and /or chloride in hypertension arises from the interpretation of conflicting data following the examination of populations or individuals.

In 1988 the British Medical Journal published the results of the ‘Intersalt’ study which examined 52 population samples and 10,079 individuals for actual blood pressure (BP) and 24 hour urinary sodium excretion using a standardised worldwide protocol. BP was significantly inversely correlated with urinary potassium excretion and positively correlated with urinary Na:K excretion ratios. The findings suggested that a reduction of daily sodium intake to 6g, in individuals over 30 years old, was likely to be associated with a 10-11mm Hg reduction in systolic blood pressure.

The findings of the Intersalt study were challenged in 1994 by the Salt Institute, the trade organisation of salt producers in the USA, prompting a series of papers published in 1996. These publications were funded by a wide range of organisations including the World Health Organisation, the Wellcome Trust, the Heart Foundations of Canada, Great Britain, Japan and the Netherlands, and the Parastatal Insurance Company of Brussels, and updated the main 1988 findings in the light of new analyses. In particular, they responded with the challenge on the relationship of 24hour sodium excretion to differences in blood pressure with age.

The view that “higher dietary sodium intake is positively associated with substantially greater differences in systolic and diastolic blood pressure in middle age than in young adulthood,” was challenged by Richard Hanneman, then president of the Salt Institute in the US. He claimed that if population samples of subjects aged 20 with a high salt intake had lower BP than samples with lower salt intakes, then the relationship between blood pressure and age would primarily be a function of initial BP rather than salt intake.” His reanalysis of the data apparently suggested that “the higher a society’s initial urinary sodium excretion, the lower its mean systolic BP” and he claimed that if four so-called ‘low salt’ centres – Kenya, Papua New Guinea and Brazil (Xingu and Yaramoto) are excluded from the analysis, then there is no relation between urinary sodium excretion and the rate of increase of BP with age.

Malcolm Law, who published an overview of the published literature in 1991 that supported the original Intersalt conclusions, was highly critical of the Salt Institute analysis, commenting on Hanneman “proposing a bizarre hypothesis that in communities where people have a high BP at 60, they have a low BP at 20, whereas people with a low BP at 60 started with a high BP.” Law further dismissed such criss-crossing of BP as “implausible.” He counter-claimed that “BP at 20-29 was higher on average in the centres with higher BP at 50-59”

Members of the Intersalt Steering Committee have also heavily criticised the Salt Institute’s re-interpretation of the data. For example they say that, “since initial (age zero) sodium excretion and BP were never measured, the claims on the salt-BP slope with age relation are artefacts of the Salt Institute’s extrapolations far beyond the observed data.”

The evidence, they say, is extensive - from animal experimentation, clinical investigation, trials, population studies, anthropology- and underlies the existence of a causal relationship between high salt intake and adverse patterns of blood pressure in populations. For example the systolic BP of chimpanzees, originally with optimal blood pressure levels on a diet with no salt added, rose 12mm Hg with a dietary increase of 5g salt/day, and rose 26mm Hg with 15g salt/day. The systolic BP was restored to optimal when animals were returned to the original diet with no salt added.

The members of the Intersalt Steering Committee further argued that “there are similarly impressive results from many studies, but none are cited by the Salt Institute, leaving the false impression that the recommendations from expert groups and public health agencies for salt reduction by the population (in the United States, the United Kingdom and elsewhere) are based solely on Intersalt findings. The findings of Intersalt agree with a whole body of concordant evidence.”         

In May 1996, Julien Midgely and colleagues published evidence based on statistical analyses of published human studies concerning the effect of changes in dietary sodium on BP, which contradicted the conclusions of the Intersalt Steering Committee. In research primarily funded by Campbell’s Institute for Research and Technology and the Medical Research of Canada, the authors examined data from 56 trials (28 hypertensive and 28 normotensive). They claimed their statistical analysis “does not support one of the goals of the (US) Nutrition Labelling and Education Act (1990), that of lowering blood pressure in the normotensive population at large, and questions the wisdom of universal dietary sodium restriction without better evidence of the long term benefits and safety of such an intervention.” They also highlighted “recent evidence linking low sodium excretion with higher mortality risk and recent reports describing the adverse metabolic effects of a low sodium diet.”

A report in The Lancet (March 1998) presented the results of an observational study of 20,729 American adults (aged 25-75), to assess the link between dietary sodium intake and death by cardiovascular disease. They found a significant link between the dietary sodium/calorie ratio and death, but not between sodium intake and death. The study found no direct evidence to support current recommendations to routinely reduce sodium intakes in healthy adults. In addition, the authors suggested that, as most industrialised societies were genetically, environmentally, behaviourally and nutritionally heterogeneous, different individuals might have different optimum sodium intakes. This could mean that generalised recommendations for dietary salt intake across a population are inappropriate.

The role of sodium in hypertension was summarised by Dave McCarron in an article in Science (August 1998). Several large scale intervention studies had shown that restriction of sodium in the diet has no effect on diastolic blood pressure, and only a minimal effect (0.7mm Hg) on systolic blood pressure. However dietary factors other than sodium markedly affect blood pressure. For example adequate calcium, potassium, magnesium intake and fresh fruit and vegetables are more effective at reducing hypertension than merely reducing sodium intake.

In a review published in 2007, McCarron claims that salt is the next major “public health disaster,” as there are concerns over members of the population with higher requirements. For example, if salt is restricted too much it may lead to additional health complications such as insufficient blood volume in unborn children and a strain on the heart if there are electrolyte imbalances in the dehydrated elderly. McCarron stressed that mineral deficiency has a more prominent effect on blood pressure than sodium and commented that salt is not a problem for healthy individuals as the kidneys process any excess sodium.

Some of the disagreements amongst clinicians and industry experts might be explained by the so-called triangular hypothesis approach first suggested in 1987 by David Booth and colleagues. Here, various rates of increase in BP with age among salt-susceptible individuals yield the well established population rise of average BP with age. This, in turn, reveals a good correlation between a high average BP in populations with a high average salt intake, when general populations with similar age profiles are compared. It follows that BP is unlikely to correlate substantially with salt intake across a non-clinical sample, especially in young people. The lack of correlation hypothesised in unsusceptible individuals would therefore mask any correlation that existed in those who are susceptible. The suggestion made was that testing for the correlation between BP and salt intake should only be examined in the higher range of blood pressures observed. Their analysis with small groups suggested that the hypothesis was sound and they declared that this approach “should succeed if salt intake makes a major contribution to hypertension.”   

Professor Dag Thelle, from the Centre for Epidemiological Research from the University of Oslo, concluded that “whether the evidence is strong enough to warrant the reduction in salt recommended (by the Intersalt authors) is, as always, a question of judgement. But useful clinical and public health actions have been undertaken on much weaker evidence.”

In addition, increasing potassium intakes to levels achievable with customary diets reduced blood pressure in normotensive and hypertensive individuals and increased urinary sodium loss. This effect of potassium on BP is supported by a 1991 meta-analysis of published reports by Cappuccio and MacGregor. It has been calculated that an increase in potassium intakes from 2.3-3.1g/day could induce a fall of 4mm Hg in systolic BP and this could possibly achieve a 2.5% reduction in deaths related to hypertension.   

The view of the UK Food industry

Since 2003, the Food Standards Agency and the Department of Health have been focusing on ways to reduce the volume of salt in processed meals, as these contribute to 75% of the nation’s salt intake. By 2006, seventy organisations and companies had committed to reducing the salt in their products and further pressure was being placed upon other major companies to commit. The aim of this initiative was to lower the national average salt intake to 6g/day.

The Food and Drink Federation (FDF) works closely with the Food Standards Agency ‘to enable autonomous consumers to make educated decisions regarding the salt content within food’. Their members provide this by making the salt content clearly visible on the packaging of food, along with the guideline daily recommendations. The FDF comments that the UK is leading the world, in terms of setting standards for other countries to follow. So far, significant sodium reductions have been made in bread; breakfast cereals have reduced levels by 43% from 1998 to 2007; biscuits and cakes have reduced sodium by16-50%; meat products, savoury snacks are 25% lower and soups and meal sauces have made a 24.5% and 28.8% reduction respectively. It is not feasible for salt levels to be cut drastically; changes must be gradual to allow the consumers palate to adapt. There is not a set level to which manufacturers should abide; as it may indeed be the salt content that distinguishes the product from competitors. The safety implications of taking out too much salt must also be considered, as it is salt that inhibits the growth of certain microorganisms.

A 2010 study by the Ashtown Food Research Centre, Dublin, looked at how reducing salt levels in frozen lasagne affected consumer acceptability.  A reduction of 0.3%, from 1.05%, could be achieved without any sensory difference.  A further reduction of 0.2% was achieved when salt substitutes, in particular KCl, were included.  KCl-salt substitutes are a possible way to reduce salt levels in foods, but have been associated with introducing a bitter taste.  This study suggests that this taste can be masked with other ingredients, such as the herbs and spices in the frozen lasagne ready meal.

In 2009, the Food Standards Agency reviewed and published the salt reduction targets for 2012. These focus on reducing the levels of salt in 80 categories of food, principally meat, canned products, bread, cereals, cheese and savoury snacks, to beyond the levels of earlier 2010 targets. It states that the previous 2004 targets have already saved the NHS and employers £1.5bn annually and the national average intake has declined by 0.9g since 2000/2001. Maintaining close links with industry and continuing public appeals should, they say, help FSA reach targets deemed as being realistic and achievable.

 Some individuals are more sensitive to salt, therefore an excess of sodium will increase their blood pressure. Research by The Salt Institute has shown that when salt intake was reduced, 30% of individuals experienced a decrease in blood pressure between 1-4mm Hg, 20% experienced an increase between 1-4 mm Hg and 50% experienced no change whatsoever.

The US Centre for Science in the Public Interest (CSPI) has commented that some members of the US food industry are not taking on board the advice of the medical community, with some companies doubling or even tripling the percentage of salt in their products. Many companies claim the high level of salt in their products is essential; preserving the product and enhancing flavouring. Nevertheless the range of salt in differing brands of the same food product varies markedly suggesting that some food companies are choosing to ignore the issue.  

The view of the pressure groups

A number of consumer pressure groups (NGOs), in the UK and elsewhere, have lobbied hard in favour of reducing salt in manufactured foods, with the proviso that the preservation characteristics of the ingredients should not be compromised.

The food industry’s position on salt has been heavily criticised by NGOs, because of what is described as “the large vested interests in the provision of the nation’s food.” Critics link “the fierce opposition to evidence linking salt to high blood pressure” to public relations companies whose clients include manufacturers of table salt.

Graham MaccGregor and Peter Sever, the convenors of the pressure group Consensus Action on Salt and Hypertension (CASH), are also highly critical of the salt and processed food industry, which, they say “has fought a careful, expensive and largely successful public relations campaign…to convince the rest of the food industry, food suppliers, politicians, nutritionists and doctors that the evidence for salt is not substantial or at least that it is not sufficient for any action and more studies are required.”

The 2008 review of salt and health and current experience of worldwide salt reduction programmes, compiled by He and MacGregor, likened a modest reduction of salt intake worldwide to “public health successes of clean water and drains in 19th century Europe”.

NGOs comment that the 2012 targets show that the UK Government is listening to the medical profession and acting on this information positively.

The view of the lay press

A number of journalists in the broadcast media and in UK national newspapers have commented forcefully on the salt debate in recent years.

Examples since the publication of the original Intersalt data include Sharon Kingman, writing in 1991, recording the publication in the British Medical Journal of papers from Dr Malcolm Law and colleagues which re-examined more than 40 earlier studies into the link between salt intake and blood pressure and 78 trials looking at salt in the diet. They claimed that “lowering salt in the diet was in the same order as stopping smoking and reducing fat in terms of measures to reduce the risk of disease.”

Following the publication of the “Intersalt revisited” papers in the British Medical Journal, media interest revived. But the contrasting conclusions of Julien Midgely and his colleagues received little attention from the media, despite the wide publicity given to their paper in advance of publication both by the Journal of the American Medical Association, and the Food and Drink Federation.

The study published in the Lancet (March 1998) was the focus of several articles in the press. Headlines such as “Death study to be taken with a pinch of salt,” (The Independent, 14.3.98) highlighted the apparent inconsistencies of the scientific evidence. In the same article, the viewpoint of Graham MacGregor (CASH) was presented, where he described the evidence that a high salt intake was a major cause of hypertension as “overwhelming.”  

The Daily Telegraph published an article surrounding the possible links of decreased sodium and depressant affects (Morris, Na and Johnson, 2009). Studies on rats showed that when deprived of salt, they began to act abnormally, losing interest in food and previously enjoyable activities. This suggested that sodium may be linked to the areas of the brain responsible for motivation, reward and desire, and may provide an explanation towards the human cravings for salty foods. Excess consumption of sodium however, does not result in antidepressant effects.

Other 2009 headlines include articles about the surprising levels of salt within seemingly ‘healthy’ products such as ready made sandwiches, which apparently contain the same salt levels as “9 packets of crisps”. This followed a survey carried out by ‘Which? magazine’ investigating leading high street brands of sandwiches.

EU Policy

In the 2007 EU White Paper on a Strategy for Europe on Nutrition, Physical Activity and Health, salt reduction initiatives were formulated. The aim was to reduce the 2008 salt consumption value by 16% in 4 years, focusing on 12 food categories including restaurant and catering meals. So far 20 countries have expressed an interest in participating. Member countries were encouraged to promote public understanding of the risks regarding high salt intakes by 2009.

Conclusion

To conclude, the salt debate was fuelled by the conflicting recommendations surrounding optimum levels of salt required for health. It cannot be denied that salt is a vital component of the diet; however salt in much of the western world is consumed to excess.

The salt reduction initiatives that are being implemented are backed up with sound evidence that report sodium to have an effect on blood pressure. It would be appropriate to comply with the FSA’s advisory 6g/day in order to reduce the risk of hypertension as well as to address the risks of gastric cancer, osteoporosis and obesity.

The British Dietetic Association recommends foods with particularly high concentrations of salt should be limited to one serving per day.  Some brands do provide low salt alternatives; and knowledge of the food labelling system is important to compare the levels of salt. Ready meals containing over 1.25g of salt (0.5g sodium) and individual items with more than 0.75g salt (0.3g sodium) are discouraged by the BDA.

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World Action on Salt (1996) Salt and Osteoporosis. Retrieved from: http://www.worldactiononsalt.com/health/Salt_and_health/osteoporosis.htm

Salt Association (2007) About Salt- Salt Facts. Retrieved from the Salt Association website: http://www.saltsense.co.uk/aboutsalt-facts01.htm

Salt Association (2007) Salt Association welcomes new study which finds no evidence of link between salt and heart disease. Retrieved from the Salt Association website: http://www.saltsense.co.uk/releases/rel24.htm

Tomson, J. and Lip, G. (2005) Blood pressure demographics: nature or nurture ... ... genes or environment? BMC Medicine (Vol 3)
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=544878

US Food and Drug Administration (1994) Guide to Nutrition Labelling and Education Act Requirements. Retrieved from: http://www.fda.gov/ora/inspect_ref/igs/nleatxt.html

Webster, J.L., Dunford E.K., Neal B.C. “A systematic survey of the sodium contents of processed foods” American Journal of Clinical Nutrition 2010, Volume 91, Pages 413-420

Information sheet originally prepared in the 1990’s by staff in IFR Communications; updated by Ellen Mitchell, 2nd yr Nutrition undergraduate from the University of Chester, June 2009 as part of her placement with IFR.

Revised and Compiled by:

Ellen Mitchell
IFR Communications
Institute of Food Research,
Norwich Research Park
Colney, Norwich NR4 7UA, UK

Tel: +44 (0) 1603 255328
Fax: +44 (0) 1603 255168
Email: ifr.communications@ifr.ac.uk