SURVEY OF SODIUM, POTASSIUM, IRON AND CALCIUM CONTENTS OF RETAIL SAMPLES OF SOME PROCESSED FOODS (BREAKFAST CEREALS AND SNACKS) SOLD IN NSUKKA, ENUGU STATE

CHAPTER ONE

INTRODUCTION

Sodium occurs naturally in almost all foods including processed foods, and, is essential for normal human functioning; however, its current intake far exceeds recommendations for good health (Brown et al., 2009). This has become a common occurrence around the world (Elliot, 2007). Excess sodium consumption is now a major public health concern worldwide (Institute of Medicine, 2010) and,  has been linked to numerous adverse health conditions like hypertension, which is a major cause of cardiovascular diseases (Turnbull, 2003;  Dickinson and Havas9, 2007), gastric cancer (Tsugane9et al., 2004), decreased bone mineral density (Devine et al., 1995) and possibly obesity (He and MacGregor, 2008). It has been estimated that 62% of stroke and 49% of coronary heart disease is caused by high blood pressure (He and MacGregor, 2010), which rises with age (Havaset al., 2004).  In recent decades, with increasing consumption of many different processed foods containing high levels of sodium (Mattes and Donnely, 1991), the perception of dietary salt has evolved to a point where it is now considered a potential health threat. In 2003, as a result of the high sodium intakes around the world, the World Health Organization( WHO) recommended a worldwide intake target of less than 5grammesof salt (or 2000 mg sodium) per day per person (World Health Organization, 2003).

Modern diet contains a high proportion of processed foods with high levels of sodium, which is inherently appealing to humans (Mattes, 1997). As seen in many developed countries, a new pattern of food intake which favours the consumption of processed foods and snacks is emerging in Nigeriadue, to the convenience of these processed foods that often encourages unhealthy eating patterns (Monteiro, 2009). This change in life style may be attributed to busy work schedule which makes dependence on these convenience foods to be on the increase. Most processed breakfast cereals have been modified in flavours and forms, thereby making them more appealing to consumers (Truswell and Brand, 1985), thus, helping manufacturers to increase sales in a highly competitive  market. Also, most people have strong preference for snacks like cake, biscuit and the wholesomeness of these snacks are not important in determining their food choice,since they do not provide overall intake of nutrients (Buthrieet al., 2002).Due to the health risks associated with excessive consumption of sodium, health agencies estimated that reducing its levels in processed and restaurant food by 50% would save 150,000 lives (Havaset al., 2004). Historically hominid diets contained high potassium and low sodium concentrations due to a diet consisting largely of fruits, vegetables and whole grains (Cordainet al., 2005). The consumption of excess sodium and insufficient potassium intake that is associated with a typical modern diet has been linked to several health effects. High intake of sodium and the low intakes of potassium has been shown to  produce and maintain elevated blood pressure in a big proportion of the population (Krishna, 1990; Karppanenet al., 2005).

Processed foods can be deliberately fortified with micronutrients like iron and calcium, to increase intake of these nutrients. This could reduce micronutrient deficiency and associated health conditions (Darnton-Hill and Nalubola, 2002). Low iron intake is associated with anaemia (Nielson and Nachtigall, 1998), while, low calcium consumption increases the risk of bone problems like osteoporosis (Heaney, 2006) and elevated blood pressure.  Increase in dietary sodium intake has a potential to influence bone loss by increasing loss of calcium. High intake of calcium has been shown to reduce systolic and diastolic blood pressure (Griffith et al., 1999).

WHO, as part of its Global Strategy on diet, physical activity and health, organized a forum and technical meeting in 2006 to review and discuss the link between high salt consumption and health, various initiatives to reduce population-wide salt intake and the cost and effectiveness of these programs. Several countries have developed strategies for significantly reducing the sodium chloride content of many processed foods (Cobcroftet al., 2008).

Based on the realization that processed foods are major contributors to the daily sodium intake, reducing the sodium content of  processed foods has therefore been  recognized as a feasible and more effective strategy for reducing daily salt intake than simply reducing the amount of salt added during cooking or on the table (WHO, 2007). Unfortunately, consumers are often unaware of the salt content of some of these processed foods that they consume regularly (Nwanguma and Okorie, 2013). This so called ‘hidden salt’ has been reported to contribute up to 95% of the salt intake of some people, especially in countries where processed foods are widely consumed (Anderson et al., 2010).  An international organization of experts on the health effects of salt WASH (World Action on Salt and Health) publicized the adverse effects of sodium chloride on health and work with governments and industry to reduce salt concentration in processed foods, catered foods and restaurant food, as well as salt added during cooking, and at the table. Achieving population wide reductions in salt intake is therefore, an important public health priority in many countries (Webster et al., 2011). Numerous health organizations and Government agencies have recommended a substantial reduction in sodium levels that would allow for manufacturers to reformulate foods and for consumers to adapt their tastes to lower sodium. The research was aimed at surveying sodium, potassium, calcium and iron content of selected retail samples of processed foods available in Nsukka, Enugu State South Eastern Nigeria, namely breakfast cereals, biscuits, cakes, meat pies, doughnut and sausage.

1.1   Processed foods

Food processing is the set of methods and techniques used to transform raw ingredients into food, or to transform food into other forms for consumption (Monteiro and Levy, 2010). Food processing can create products that require little or no preparation on the part of consumers (Brunner et al., 2010). It produces attractive, marketable and often long shelf-life food products. Methods used for food processing are canning, freezing, dehydration, aseptic processes (Monteiro and Levy, 2010).

Processed foods are foods that have been altered from their natural state for safety reasons or for convenience.  They are designed to be less perishable, more durable and more portable than prepared foods and, often contain substantial amounts of sweeteners, preservatives and appealing ingredients such as chocolates, peanuts and specially designed flavours (such as flavoured potato chips) (Street Foods, 2006). Processed foods are major contributors to population dietary salt intake (i.e. the total number of sodium intake from all sources including sodium chloride, monosodium glutamate or any other sodium containing preservatives or additives.  They account for more than three-quarters of all sodium consumed as shown in fig.1 (Mattes, 1997; FSANZ, 2007). The reduction of salt (sodium) in processed foods is therefore a major challenge for health authorities across the globe and in many cases the challenge is currently being set to the food industry to change formulations and, reduce dietary sodium consumption thereby reducing hypertension and associated risks on cardiovascular disease (Webster et al., 2010; Xing, 2012).

Fig. 1: sources of sodium (Mattes and Donnelly, 1991)

1.1.2    Reasons why processed foods contain salt

The utility of sodium has made it a crucial ingredient for many processed foods. Sodium improves the sensory properties of foods, by increasing saltiness, decreasing bitterness, and increasing sweetness and other congruent flavour effects (Keast and Breslin, 2003).  Salt is added to processed foods for the following reasons:

1. Sodium chloride (salt) can prevent the development of food-borne pathogens. It reduces water activity in foods thereby acting as a critical hurdle to control growth of pathogens and spoilage organism (Delahunty and Piggott, 1995; Hutton, 2002).Because food manufacturers and producers often want to prolong the shelf life of their products, the amount of sodium in many processed foods is increased to certain levels.
2. Sodium helps bind ingredients and enhances the colour of the food.In breakfast cereals,it plays a key flavour-blending role, added at about 1.25-1.75% by weight.
3. Salt improves taste flavour enhancement and aids in stabilization.( Lynch et al., 2009; Taormina, 2010)
4. Salt is also responsible for fermentation control and texture in yeast-raised breads.
5. Salt plays a part in fat emulsification, thus diminishing the loss of fat and water during cooking in products such as sausages.
6. In most baked goods like biscuits, salt is used to improve product taste and flavour. Without salt, many baked goods will have an insipid taste. Salt not only sustains the “life” of the food but also, provides a more economical approach to most companies. Thus, if the food is more processed, it is likely that the sodium content is higher. Some of the most popular leavening agents contain sodium, including baking soda (sodium bicarbonate) accounting for 95 percent of the sodium in these products.
7. Salt has been found to improve the perception of product thickness, enhance sweetness, mask metallic or chemical off-notes, and round out overall flavour while improving flavour intensity (Gillette, 1985).
8. Various sodium-containing ingredients have been known to reduce the bitterness of certain compounds found in foods, including quinine hydrochloride, caffeine, magnesium sulfate, and potassium chloride (Breslin and Beauchamp, 1995)

1.2   Snacks                

Snacks are quick foods, oftentimes smaller than that of a regular meal, usually derived from one or more basic food items, and are eaten between meals. They give a feeling of satiety. Snacks come in a variety of forms including packaged and processed foods and items made from fresh ingredients at home. They can be processed from food group origin such as cereals, pulses, starchy fruits, roots and tubers, beef, dairy and poultry (Okoruwa, 1997). Processed snack foods are designed to be less perishable, more durable, and more portable than prepared foods and they often contain substantial amounts of sweeteners, preservatives, and appealing ingredients. They constitute a major meal for a handful of indigenes due to their availability, affordability and accessibility (Draper, 1996). Commonly consumed snacks in Nigeria include baked products (biscuits, cake, hamburger, meat pie and sausage rolls), fried and roasted snacks (cashew nut, doughnuts, peanuts and popcorn), and nuts. Snack food are patronized in leaps and bounds by individuals to satisfy their hunger pangs or as refreshments without giving cognizance to the preparation and packaging methods or nutritional contents in most cases.

 

 

 

 

 

1.3       Breakfast cereals

Breakfast cereals are foods made from processed grains and are often eaten with the first meal of the day. It is often eaten cold, usually mixed with milk (e.g. cow's milk, soy milk, rice milk, almond milk), juice, water, or yogurt, and sometimes fruit, but may be eaten dry. They are good sources of micronutrients (Bonner et al., 1999). Fortified breakfast cereals are of great importance (McNulty et al., 1994) since they contribute significantly to iron and calcium intakes (McNulty et al., 1996). They can be categorized into, traditional (hot) cereals and ready-to-eat (cold) cereals.Traditional (hot) cereals require further cooking or heating before consumption while, cold cereals can be consumed from the box or with the addition of milk (Tribelhorn, 1991)

1.3.1   Traditional (hot) cereals

Traditional (hot) cereals are those requiring cooking or heating prior to consumption and are made from oats, farina (wheat), rice, and corn (Fast, 1990). Almost all (99 percent) of the traditional cereal market are products produced from oats (over 81 percent) and farina (approximately 18 percent). Cereals made from rice, corn (excluding corn grits), and wheat (other than farina) make up less than 1 percent of traditional cereals.

 

1.3.2   Ready-to-eat cereals

Ready-to-eat breakfast cereals are processed grain formulations, suitable for human consumption without further cooking in the home. They are relatively shelf-stable, lightweight, and convenient to ship and store. They are made primarily from corn, wheat, oats, or rice, usually with added flavor and fortifying ingredients. These groups are flaked cereals, extruded flaked cereals, gun-puffed whole grains, extruded gun-puffed cereals, oven-puffed cereals, shredded whole grains, extruded shredded cereals, and granola cereals (Fast, 1990).

  1.4     Sodium

Sodium is an essential nutrient, the cation that performs a number of vital roles in the body including, regulating extracellular fluid volume and plasma volume, maintaining the volume of extracellular fluid, osmotic pressure, acid-base balance and transmission of nerves impulses (Geerling and Loewy, 2008). It determines membrane potential of cells,  participates in the active transport of some molecules across cell membranes, facilitates absorption of nutrients such as glucose (sugar), amino acids (protein constituents) and, is essential for myriad biological processes including fluid balance and muscle contraction (Webster et al., 2010). Sodium also occurs naturally in almost all foods and is present in processed foods due to the use of some food additives, for example, sodium bicarbonate (baking soda) used as a raising agent in cakes and biscuits. Most of the sodium in our food comes from sodium chloride (table salt) which is the major dietary source of sodium and in western diets; starchy foods are one of the major dietary contributors (e.g. breads, snacks and crisps). Sodium chloride is a commonly used food ingredient which provides many technological functions such as flavour enhancement, preservation and texture modification (Hutton, 2002).

High levels of dietary sodium have however, been linked to health conditions such as hypertension. World Health Organization (WHO) recommendations indicate that, in order to prevent chronic diseases, an adult upper daily limit intake of sodium should be less than 87 mmol Na/day (<5 g NaCl/day) (WHO, 2007). The National Research Council of the National Academy of Sciences recommends even less, 1,200 to 1,500 mg of sodium each day for adults (Institute of Medicine, 2010). However, leading scientific organizations and governmental agencies advise limiting sodium intake to 2400 mg or less daily (Dickinson and Havas, 2007).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.4.1 Sources of sodium

Sodium is also found in many other ingredients used in food processing. Examples of sodium-containing ingredients and their uses in foods as shown in table 1

 

 

Compounds	Uses
Baking powder	leavening agent
Baking soda	leavening agent
Monosodium glutamate	flavour enhancer
Sodium benzoate	preservative
Sodium caseinate	thickener and binder
Sodium citrate	control acidity in soft drinks and fruit drinks
Sodium nitrite	curing agent in meat, provides color, prevents botulism (a food poisoning)
Sodium propionate	mold inhibitor (inhibits molds in bread and cake)
Sodium phosphate	emulsifier, stabilizer, buffer
Sodium saccharin	artificial sweetener
Disodium phosphates	quick cook cereals and processed cheeses
Sodium alginate	Used inchocolate milk and ice cream; holds chocolate in suspension

Table 1: sodium containing ingredients and their uses (Institute of Medicine, 2012)

1.4.2     Sodium guidelines or acceptable nutrient claims of sodium by Food and Drugs Administration (FDA).

Terms	Sodium amount
Sodium – free	less than 5mg per serving
Very low sodium	35mg or less per serving
Low sodium	140mg or less per serving
Medium sodium	≥200<500mg per serving
High sodium	>500mg per serving

Table 2: sodium guidelines by FDA (Food Facts, 2014).

 

 

1.5   Calcium

Calcium helps build strong bones and teeth, regulates muscle contraction, including the heartbeat and makes sure blood clots normally (Heaney and Weaver, 1990). Most highsodium foods increases the risk of calcium loss(Ho et al., 2001).  Concerns regarding bone health and sodium intake stem from the observation that a high salt intake is associated with increased urinary calcium excretion. It has been estimated that urinary calcium levels increase by approximately 1mmol per 100 mmol sodium intake (Nordinet al., 1993).Cutting back or eliminating these high-sodium processed foods therefore, is a great way to lower calcium excretion and risk of bone problems (Devine et al., 1995), hence, marginal deficiency of calcium may play a role in stimulating human salt intake (Tordoff, 1992). This suggest that one strategy to reduce salt liking and, perhaps intake would be to encourage increased calcium consumption, which is already strongly recommended for bone health (HHS, 2000).  By encouraging milk consumption, breakfast cereals are also an excellent way of helping to ensure adequate calcium intake in both children and adults.Research has indicated that calcium intake at the recommended level (1,000-1,200 mg/day) (Ma et al., 2007), may be helpful in preventing and treating moderate hypertension(Miller et al., 2000).Recommendations however, vary for different stages of growth and reproduction (COMA, 1991).

 

 

 

 

1.6   Iron

 

Iron is an essential mineral that plays important roles in the body(Boldt, 1999 ; Conrad et al., 1999).  The majority of functional iron within the body is present in haem proteins, such as haemoglobin, myoglobin and cytochromes, which are involved in oxygen transport or mitochondrial electron transfer. Many other enzymes also contain or require iron for their biological function(Lieu et al., 2001). Fortified breakfast cereals are an important source of iron in the diet, providing 20% of mean total iron intake. These fortifications have contributed to increased dietary iron intake and reductions in iron deficiency anaemia (Whittaker et al., 2001). Breakfast cereals fortified with vitamins and minerals provide at least 17% for iron. RDI (Recommended Daily Intake) for iron is 10-15mg/day however; recommendations vary for different stages (COMA, 1991)

 

1.7   Potassium

Potassium is an essential dietary micronutrient responsible for smooth muscle contractility, fluid balance, neural signal transduction and cardiac function (Wardlaw and Hampl, 2007). Adequate intake for the prevention of chronic disease for potassium is 120 mM/day (4.6g) (WHO, 2003; Champagne, 2006). The increase in potassium intake makes it possible to reduce blood pressure. This phenomenon can be explained by potassium’s capacity to increase excretion of sodium and by the vasoactive effects on blood vessels.

Potassium is present in many foods but not in large quantities. The best sources of potassium are fresh foods (fruits and vegetables) that have undergone little processing. These diets are high in potassium but low in sodium and hence, can reduce the risk of hypertension i.e., reduce blood pressure (Adrogué and Madias, 2008). Some processed foods might contain potassium but food manufacturers tend to flavour their products with a lot of sodium, and, don’t balance out the sodium additives with potassium additives.

The equilibrium between potassium (K⁺) and sodium (Na²⁺) is fundamental. Due to the imbalance between sodium and potassium intake the kidney retains more sodium and releases potassium. Too much sodium retained in the water in the body is thus stored and it expands the body fluids, and this increases blood pressure and affects the kidney and heart functions. Hence the more processed foods one eats the more sodium intake will exceed potassium intake.

 

1.7.1Sodium-potassium interactions

Through a mechanism known as the “sodium-potassium” pump, as shown in fig. 2, sodium and potassium work together closely to initiate muscle contraction and nerve transmission, and to maintain the body's normal distribution of fluid (Debska et al., 2001). Sodium potassium pump is an enzyme based   mechanism of active transport driven by the energy generated by Na⁺,K⁺-ATPase, by which sodium (Na⁺) is extruded from a cell and potassium (K⁺) is brought in, so as to maintain the low concentration of sodium and the high concentration of potassium within the cell with respect to the surrounding medium. Most of the potassium in the body is stored inside of your cells, while most of the sodium in your body is stored in the fluid that surrounds the cells (He and Macgregor, 2001).

During muscle contraction and nerve transmission, potassium leaves the cell and sodium enters the cell via the “sodium-potassium pump.” (Sigworth, 2001).  This transfer causes a change in electrical charge within the cell, which initiates the muscle contraction or the nerve impulse. Because sodium attracts water, once the muscle contraction or nerve impulse is initiated, the sodium is immediately pumped out of the cell to prevent water from entering the cell and causing the cell to swell or burst, and potassium is pumped back into the cell (Sobey, 2001).  A high concentration of intracellular potassium is necessary for vital processes such as protein biosynthesis, certain enzyme activities, and maintenance of the membrane potential of excitable cells.

 

 

 

Fig. 2:  Mechanism of sodium-potassium pump (Guyton and Hall, 1994)

 

• The pump, while binding ATP, binds three intracellular Na⁺ ions.
• ATP is hydrolyzed, leading to phosphorylation of the pump at a highly conserved aspartate residue and subsequent release of ADP.
• A conformational change in the pump exposes the Na⁺
  ions to the outside. The phosphorylated form of the pump has a low affinity for Na+
  ions, so they are released.
• The pump binds 2 extracellular K⁺ ions. This causes the dephosphorylation of the pump, reverting it to its previous conformational state, transporting the K⁺ ions into the cell.
• The unphosphorylated form of the pump has a higher affinity for Na⁺  ions than K⁺ions, so the two bound K+ ions are released. ATP binds, and the process starts again.

 

1.7.2   Significance of the sodium potassium ratio

Maintaining optimal sodium-potassium ratio is important to health. Imbalance in the ratio can lead to health complications like heart disease and deaths (Quanhe, 2011). The easiest way to achieve this imbalance is by consuming diets of processed foods that are significantly low in potassium, while high in sodium. Some studies have shown the effect of the sodium potassium ratio on blood pressure and cardiovascular disease to be more significant than the effect of either electrolyte considered individually (Poulteret al., 1990; Cook et al., 2009). Excess sodium and insufficient potassium intakes are a major health concern in the developed world as it plays a role in the manifestation of hypertension, stroke and cardiovascular diseases as shown in fig. 3. The totality of existing evidence suggests that both sodium and high potassium intakes are necessary for the greatest protection against high blood pressure and cardiovascular diseases (Xieet al., 1992; Dyer et al., 1994).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 3: The relationship between sodium, potassium and blood pressure in the pathogenesis of hypertension (Adrogué and Madias, 2008)

 

1.8       Methods/strategies for sodium reduction in processed food.

A reduction in population sodium intake is a global public health priority (WHO, 2OO7). Lowering sodium (sodium reduction) is one of the most important dietary changes that all need to make and is a responsibility in many quarters like industry, governments, and including consumers. Strategies aimed at lowering the sodium content of processed foods have the potential to decrease sodium in the food supply, thereby decreasing population wide sodium consumption. The magnitude of potential health gains achievable through population based sodium reduction  has been found to be highly significant (Asariaet al., 2007; Webster et al., 2010), hence  decreasing sodium intakes would assist the prevention of age related rises in blood pressure and therefore cardiovascular disease risk (Neal et al., 2006).

 

1.8.1   Role of food industries

The addition of sodium to food by food processors accounts for about 75% of dietary sodium consumption (James et al., 1987; Hypertension Canada, 2009); hence, sodium reductions within these foods could significantly contribute to an overall dietary decrease in sodium.  A food industry strategy is an important component of many sodium reduction programs worldwide. They should comply with all applicable legislative and regulatory provisions for the production, marketing and sale of foods and aim for sodium reduction in foods to the lowest level possible while maintaining food safety and consumer acceptance. A World Health Organization (WHO) report, Reducing Salt Intake in Populations, underlines the need to work directly with food manufacturers as a cornerstone of any successful national salt reduction campaign (World Health Organization, 2006). There is a clear need for the food industry to identify technical routes to enable functionality to be modified, flavour to be enhanced and shelf life to be preserved whilst reducing the concentration of sodium salts and maintaining the consumer experience. They should reformulate foods that are low in sodium and high in potassium.  However, though excessive sodium consumption has long been of great concern to health professionals, most food processors have done little to reduce sodium levels. In one study, CSPI (Center for Science in the Public Interest), has monitored the sodium content of 100 popular foods since 1983 and, observed that of all the 69 products still marketed in 2004, the average sodium content decreased by just 5 percent (from 592 mg to 564 mg) (Jacobson, 2005).  However, there has been some success in reducing salt content of these processed foods in some developed countries. Food manufacturing industries need to be committed in their effort to reduce sodium content in these processed foods. To achieve these, they can carry out the following strategies

1.8.1.1  Sodium reduction by stealth

This strategy refers to a gradual reduction of salt in processed foods that is unnoticeable to consumers (Kilcast and Ridder, 2007). The foundation of the approach is based on setting sodium reduction targets for different product categories which industry are expected to meet within an allocated time period. Perceptual studies with taste show that people are generally unable to detect differences between two concentrations of a taste substance when the difference is less than approximately 10 percent (called a Just Noticeable Difference (JND), (Pfaffmannet al., 1971). It has also been suggested that a gradual reduction of salt in food, in incremental steps, would be unnoticed by the consumer. According to this argument, if incremental reductions were instituted regularly (e.g., once each year or even more frequently), it would be possible to substantially reduce the salt content of foods over the course of several years without the consumer noticing. Cauvain (2007)reported that 25 percent of the salt in bread could be eliminated, over a cumulative series of small decreases, without people recognizing a taste change (Cauvain, 2007). This strategy has been successful with the sodium content of most processed foods in supermarkets being reduced by 20-30% (Heet al., 2008). For example, the Australian Sodium in Bread study progressively lowered the sodium content of bread served to a group of hospital patients from 100% to 75% over a six-week period. Those in the intervention group were unable to detect the changes (Girgiset al., 2003). In another study that examined a very small number of individuals (Bertinoet al., 1982) reported that after consuming a diet with a 30–50 percent overall reduction in sodium content for 2 to 3 months, volunteers gradually developed a preference for foods with lower salt levels. In other words, they acclimated to the lower-salt diet.

This is an attractive strategy for reducing salt in foods while maintaining their acceptability, and several food manufacturers are reported to have already undertaken it. However, advancements in several research areas may optimize the implementation of such a strategy. First, industry has not undertaken reduction of sodium across all foods, so there may be some individual products for which reductions may be limited. Secondly, it is likely that there will be a limit to reductions that can be achieved by simply lowering sodium content without additional reformulation and taste changes, but there are no published data testing the limits of this strategy. It seems likely for many foods that at some point further reductions may not be possible while maintaining consumer palatability. Determination of where the point of limited reductions resides will vary by food item and is a focus of industry research during the reformation process. Thirdly, since salt has many sensory functions in foods in addition to making it taste salty, it is unclear whether changes in these other functions would go unnoticed following small reductions or whether additional changes in food formulations would be required. However, changes can only be made gradually to maintain consumer acceptability and allow for the limits of technology and microbial safety. Reformulation of products must be technically feasible and safe, and their taste must remain acceptable to consumers.

 

 1.8.1.2 Use of salt substitutes

An ideal situation would be the replacement of sodium with a compound that elicits a similar pure saltiness when consumed.  Salt substitutes, are compounds or ingredients that allow for the partial replacement of salt without affecting saltiness of products. There are many different types of substitutes used within the food industry. Sodium chloride replacers such as potassium chloride, calcium chloride and magnesium sulfate have been used to replace or enhance salt taste in a number of food products (Van der Klaauw and Smith, 1995). While these compounds do contribute a certain salty taste quality, they may also provide undesirable after tastes such as bitter, metallic and astringent tastes, which has limited their current use in food manufacturing (Reddy and Marth, 1991; Lawless et al., 2003). Potassium chloride is currently the most commonly used material to replace sodium in foods (Dotshet al., 2009). In addition to producing a salt like taste, potassium chloride also elicits a bitter / metallic taste (Van der klaauw and Smith, 1995; Beauchamp and Stein, 2008). However, when potassium chloride is used in high concentrations the bitter/mellic taste dominates over the salty taste, often causing foods to become unpalatable thus limiting the utility of potassium chloride as a salt substitute (Ainsworth and Plunkett, 2007). Potentially, the intensity of perceivable bitter taste and associated off flavours can be decreased by ―bitter blockers, or sweeteners such as sucrose. Most companies have been reducing sodium in food products by replacing NaCl (salt) with sodium-reduced, potassium and magnesium enriched mineral salt called Pansalt. The significance of the success of using Pansalt in manufactured food products has sparked an interest in the development and use of salt substitutes. Other types of salt flavour enhancers are Hydrolysed Vegetable Proteins (HVP), yeast extracts and mono-sodium glutamate (MSG) (Brandsma, 2006). Arguably salt taste is the most important function of NaCl since our innate liking for salt taste in foods has an important role in food choice and acceptance.

1.9Roles of government

Sodium reduction strategies led by government and food processing industry are projected to be cost effective (Asariaet al., 2007). Government need to develop programs and adopt regulations that would decrease the sodium content of the food supply for the sake of the public’s health by considering the following measures:

1. They should provide generous funding for FAD ( Food and Drug Administration) division of sodium reduction to develop regulations
2. They should press food industry to use less salt.
3. Monitoring sodium levels in foods and diet.
4. Setting sodium limits for categories of processed foods that are the biggest sources of sodium. This limit could be based on the levels in the lowest sodium brands or on the median sodium content in each category.
5. Provide funding for the department of health and human services to educate the public about sodium.
6. Since sodium is only one of many factors that cause cardiovascular and other diseases, the government should sponsor major campaigns to promote diets rich in vegetables, beans, fruit, whole grains, nuts, and seafood, along with lean meat and poultry and fat-free or low-fat dairy products. It should also help schools serve more healthful meals, provide financial incentives to farmers to produce more healthful foods, and give bonus food stamps to enable recipients to buy more fruits and vegetables.
7. The government should support measures to encourage physical activity.
8. Target major food producers or trade organizations to standardize the sodium content of foods that are distributed locally and internationally.
9. Enforce clear mechanisms to monitor the food producers activities' related to the salt composition of food products (this monitoring system should cover not only processed foods, but also catering industry, restaurants and meal deliveries in general).
10. They should support the reduction of average sodium intake to 2300 mg per, through an awareness and education campaign to inform Nigerians on sodium as part of healthy eating.

1. Supporting research related to sodium reduction in the areas of food science and food technology, health and human physiology, and evaluation and monitoring.

12. Develop and enforce clear monitoring mechanisms – not only for producers of processed foods, but also caterers, restaurants and others involved in commercial meal preparation.
13. Allocate a clear budget for the salt reduction program and employ qualified staff for monitoring.
14. Assist small businesses (e.g. bakeries, restaurants, local cheese producers) to work toward sodium‐reduction targets. Assistance might take the form of toolkits on how to reduce salt in specific products, free information sessions, or provision of consulting services by qualified technical staff.
15. Encourage public declaration of sodium content through labels on all processed food and meals. Labelling should be clear, simple, coherent, and consistent with the key message of the accompanying consumer awareness campaign.

Most countries like UK( Foods Standard Agency, 2009), Canada (Health Canada, 2009) , USA (New York City Department of Health and Mental Hygiene,2009) , and Australia (Webster et al., 2010) have developed model to decrease sodium intake  by promoting reductions in the sodium content of processed foods. Their strategies includes- assessing baseline sodium amounts in processed foods, establishing voluntary sodium reduction targets by food category, recommendations in the areas of education and monitoring progress with time.

1.10     Roles of consumers

Consumers have to reduce their daily dietary salt and consciously reduce the intake of these processed foods that contribute to three quarter of sodium consumed. Consumers should also, become more aware of nutrition issues and food composition with the aim of making more informed choices at the grocery store, while cooking at home, or when eating out and, educate themselves and their families on healthy living practices, including healthy eating and adequate physical activity. According to Creswell(2010) acquiring a taste for salt is a learned behavior and can be unlearned. However, interventions targeting lifestyle are difficult to implement and usually have quite limited success (Appel, 2006).

 

1.10.1    Sodium-restricted diets:

Sodium-restricted diets have been shown to be effective at reducing blood pressure,however; support is often required in the form of extensive dietary counseling or in the provision of low salt food products. Community-based intervention trials, however, have demonstrated that only 20–40% of participants were able to reduce their sodium intake below the recommended upper limit of 100 mmol Na/day (5.8 mg NaCl/day) despite intense counseling (Karanjaet al., 2007). Due to the need for counseling, this intervention would not be feasible at a population level. Sodium reduced diets are difficult to maintain as they often require a change in dietary behavior (Hooper et al., 2002). This behavioural change is difficult to develop. Additionally, having an innate liking for salt taste in a food environment rich in sodium makes compliance with low sodium diets difficult. Hooper and Sacks suggested that an overall sodium reduction could be more effectively achieved by reducing the sodium content of processed foods than by just giving dietary advice alone (Sacks et al., 2001; Hooper et al., 2002; NHF, 2006).

With an appropriate food industry response, combined with consumer education and knowledgeable use of food labels, the average consumer should be able to choose a lower-sodium diet without inconvenience or loss of food enjoyment. However, in the continued absence of voluntary measures adopted by the food industry, new regulations will be required to achieve lower sodium concentrations in processed and prepared foods.

 

1.11     Responsibilities/roles of Food and Drug Administration in Nigeria (NAFDAC) in regulating sodium content in processed Foods

The responsibilities for regulating sodium content of processed foods in Nigeria devolve within many government organizations and agencies although NAFDAC (Nigeria’s FDA equivalent) has played the lead role over the past decade. The scope of this organization (NAFDAC) is to regulate, protect and promote public health by ensuring the wholesomeness, quality, safety and efficacy (as applicable) of food, packaged water, drugs, cosmetics, medical devices, chemicals and detergents (referred to as regulated products) used in Nigeria

 

General requirements

Any health claim made in the label or package of the food should respect the Codex Alimentarius recommendations (Codex Alimentarius, 2004).  False advertising/labelling claims must be firmly avoided. National authorities should ensure that any nutritional labelling system implemented is clear, simple, culturally-acceptable and easily understandable by the population, independently of their literacy or socioeconomic level.

NAFDAC regulations require food labeling to be informative and accurate and not fraudulent or misleading. The nutrient profiles for food and/or certain categories of food shall be established taking into account in particular:

1. the quantities of certain nutrients and other substances contained in the food, such as fat, saturated fatty acids, trans-fatty acids, sugars and salt/sodium
2. the role and importance of the food (or of categories of food) and the contribution to the diet of the population in general or, as appropriate, of certain risk groups
3. The overall nutritional composition of the food and the presence of nutrients that have been scientifically recognized as having an effect on health.
4. The nutrient profiles shall be based on scientific knowledge about diet and nutrition, and their relation to health.

 

NAFDAC also requires that nutrient declarationbe mandatory for foods for which nutrition claims are made. Nutrient declaration shall be voluntary for all other foods. Where nutrient declaration is applied, the declaration of the following shall be mandatory:

1. Energy value; and
2. The amounts of protein, available carbohydrate (i.e., carbohydrate excluding dietary fibre) fat, salt/sodium and total sugar (NAFDAC, 2010)

A food may be labeled “sodium free” if it contains less than 5 mg per serving, “very low sodium” (< 35 mg/serving) or “low in sodium” (< 140 mg/serving) (Cooper, 1997). However, many processed foods in Nigeria do not meet all these nutritional requirements.

Most does not specify the amount of ingredients like sodium in their food products. Because the amount of most dietary sodium is “hidden” in processed / packaged foods, it is impossible for consumers in these countries to know how much salt they are eating.  Some exaggerate their nutritional claims.

There is need for NAFDAC to reduce the negative effects of  exaggerated nutritional claims by carefully monitoring these food products to make sure that they comply with these nutritional standards. They should also make sure that if the chief sources are foods imported from other nations, a way must be found to influence the content of food entering the domestic market, and to ensure that a particular product is not sold with higher salt content in the domestic market than in other nations. They should also, set up mandatory and voluntary targets for sodium for different food categories and sub-categories. They should track and access sodium content changes in food category over aperiod of time. More so, a database has to be provided to monitor this change, since setting of sodium targets for food categories and the establishment of a database to monitor the sodium contents of foods have been core to the success of national reduction programs (FSA, 2009). They should encourage food manufacturers to gradually reduce sodium content in their food since, reduction could be easily achieved through this means than by dietary advice alone (Hooper et al., 2002 and Sacks et al., 2001). NAFDAC should ensure food manufacturers comply with nutrient declaration claims on foods; provision of disease risk reductions claims to help consumers make informed choices thereby reducing their risk of developing chronic disease; ensuring that claims are consistent and non-deceptive. NAFDAC and similar regulatory organizations should launch salt reduction program to substantial reductions in the sodium content of many processed foods, particularly those known to be major contributors to sodium intake (Mhurchuet al., 2011). However, according to a presentation made at the 2006 WHO Forum in Paris Nigeria has been complimented as one of the Africa countries that   have dietary guidelines for salt intake (World Health Organization, 2007).

 

1.12Effect of sodium reduction in processed foods

Changing a population’s dietary habits is complex. Taste is one of the most important factors in food choice. In general, attempts to reduce dietary sodium intake through sodium restricted diets have shown short term success but have lacked long term sustainability and practicality for large populations due to high levels of sodium in processed foods and the significant contribution of processed foods to diet (James et al., 1987; Hooper et al., 2002).

Also, a reduction of sodium chloride in foods is accompanied by a loss of palatability of those foods (Mattes, 1997; Karanjaet al., 2007). Humans have an innate liking for salt taste (Chandrashekaret al., 2006) and as a result, when large reductions in sodium content occurthere is a decline not only in saltiness of the product, but also in palability and consumers acceptance ( Beauchamp et al., 1982;  Mattes, 1997). This is an issue for the food industry as dramatic changes in product flavour profiles could potentially alienate consumers and encourage them to choose other product brands ( Brandsma, 2006; Dotschet al., 2009). Estimates by the Consensus Action on Salt (CASH) show that a 10-25% reduction in sodium is undetectable by human senses (Consensus Action on Salt and Health, 2006).  The ideal solution would be to reduce the concentration of sodium in the food while retaining optimum saltiness for palatability.

Salt has other effects on the flavour of foods by enhancing the taste of some other ingredients and suppressing or masking bitter flavours. Perception of bitterness is genetically controlled. It has been estimated that about 25% of the population are non-tasters (insensitive to ordinary levels of bitter compounds) and about 25% are supertasters (very sensitive to bitter compounds) (Kilcast and Ridder, 2007). However, with a continual decline of sodium from products it is inevitable that a point will be reached where a difference in flavour profile will be detectable by consumers. Therefore, to achieve large sodium reductions in foods, an approach is required where the salt taste elicited by sodium can be replaced so that the consumer acceptance is not negatively affected (Dotschet al., 2009)

Reducing sodium chloride level may affect texture and other quality characteristics including, moisture levels, fat content, pH, starter cultures, various additives, and processing conditions (Dotschet al., 2009). For example, sodium chloride is able to bind proteins and fats and hold water. Therefore, meat batters with low sodium need to have a sodium replacer, which not only replaces salt taste, but also needs to compensate for the other functions, which are lost when sodium is decreased (Xiong, 2007). In addition to safety risks and processing challenges involved in producing low sodium foods, there is also an economic consideration. Sodium chloride is relatively cheap and any substitute used will increase the cost of the product. Furthermore, in order to find suitable salt replacers, bitter blockers and or flavour enhancers substantial effort and money needs to go into research, development and consumer testing. The food industry will need to take all functions of sodium in foods into account when addressing sodium reduction.

1.13   2012 salt targets of some food categories by UK Food Standard Agency (FSA, 2009).

FOOD CATEGORIES	TARGETS FOR 2012 (mg sodium/100g)
Sausages	450 sodium (maximum)
Breakfast cereals	244 sodium (average recommended) 450 sodium (maximum)
Cakes and pastries	200 sodium (average recommended) 400 sodium (maximum)
Biscuits   Sweet filled biscuits Sweet unfilled biscuits	270 sodium (average recommended) 450 sodium (maximum)
Table 3: salt targets of food categories by UKFSA Savoury biscuit unfilled	550mg sodium (average recommended) 800mg sodium (maximum)

1.14 Standard amount of sodium in some food categories set by NAFDAC

Food categories                                                      standard amount
Biscuits	626mg
Cake	300mg
Cornflakes	1005mg
Oatmeal	610mg

Table 4:  Standard amount of sodium by NAFDAC

                                                                  

1.15    Aim and objectives of the research

1.15.1 Aim of the study

The study was aimed at determining the sodium, potassium, iron and calcium levels in       some selected processed foods (snacks and breakfastcereals)

1.15.2 Specific objectives of the study

• To determine the sodium, potassium, iron and calciumlevels in selected processed foods (biscuits, sausages, cakes/pastries and breakfast cereals).
• To estimate the amount of sodium, potassium, iron and calcium consumed from each type of food relative to the Recommended Daily Allowance (RDA).
• To compare the mineral contents (sodium, calcium, iron and potassium)in the selected processed foods (biscuits, sausages, cakes/pastries and breakfast cereals).
• To compare the sodium contents of samples to targets set by National Agency for Food and Drugs Administration and Control (NAFDAC) and United Kingdom Food Standard Agency (UKFSA).

 

$39.69 – DOWNLOAD FULL PROJECT DOWNLOAD FULL PROJECT Added to cart