Etiket Arşivleri: Can food additives cause allergies
The use of food additives is an emotional topic which continues to provoke consumer concern.
Despite modern-day associations food additives have been used for centuries. Food preservation began when man first learned to safeguard food from one harvest to the next and by the salting and smoking of meat and fish. The Egyptians used colours and flavourings, and the Romans used saltpetre (potassium nitrate), spices and colours for preservation and to improve the appearance of foods. Cooks regularly used baking powder as a raising agent, thickeners for sauces and gravies, and colours, such as cochineal, to transform good-quality raw materials into foods that were safe, wholesome and enjoyable to eat. The overall aims of traditional home cooking remain the same as those prepared and preserved by today’s food manufacturing methods.
Over the last 50 years, developments in food science and technology have led to the discovery of many new substances that can fulfil numerous functions in foods. These food additives are now readily available and include; emulsifiers in margarine, sweeteners in low-calorie products and a wider range of preservatives and antioxidants which slow product spoilage and rancidity whilst maintaining taste.
Food additives serve five main functions:
1. Maintain product consistency
Emulsifiers provide a consistent texture and prevent products from separating. Stabilizers and thickeners provide a uniform texture. Anticaking agents enable substances to flow freely.
2. Improve or preserve the nutrient value
Fortification and enrichment of foods has made it possible to improve the nutritional status of the U.S. population. For example, vitamins and minerals are added to many foods including flour, cereal, margarine, and milk. This helps to make up for vitamins or minerals that may be low or completely lacking in a person’s diet. All products that contain added nutrients must be labeled.
3. Maintain the wholesomeness of foods
Contamination from bacteria can allow food-borne illnesses to occur. Preservatives reduce the spoilage that air, fungi, bacteria, or yeast can cause. Preservatives such as antioxidants help baked goods preserve their flavor by preventing the fats and oils from becoming rancid. They also keep fresh fruits from turning brown when exposed to the air.
4. Control the acidity and alkalinity, and to provide leavening
Specific additives help change the acidity or alkalinity of foods to obtain a desired taste, color, or flavor. Leavening agents that release acids when they are heated react with baking soda to help biscuits, cakes, and other baked goods rise.
5. Provide color and enhance flavor
Certain colors improve the appearance of foods. There are many spices and natural and synthetic flavors that bring out the best in the flavor of food.
2. What are food additives and why are they necessary?
A food additive is defined as “any substance not normally consumed as a food in itself and not normally used as a characteristic ingredient of food whether or not it has nutritive value, the intentional addition of which to food for a technological purpose in the manufacture, processing, preparation, treatment, packaging, transport or storage of such food results, or may be reasonably expected to result, in it or its by-products becoming directly or indirectly a component of such foods” (Council Directive 89/107/EEC). Many food additives are naturally occurring and some are even essential nutrients; it is the technical purpose that leads to these being classified as food additives and given an E number.
Food additives play an important role in today’s complex food supply. Never before has the range and choice of foods been so wide either in supermarkets, specialist food shops or when eating out. Whilst a shrinking proportion of the population is engaged in primary food production, consumers are demanding more variety, choice and convenience alongside higher standards of safety and wholesomeness at affordable prices. Meeting these consumer expectations can only be achieved using modern food processing technologies which include the use of a variety of food additives proven effective and safe through long use and rigorous testing.
Additives carry out a variety of useful functions which we often take for granted. Foods are subjected to many environmental conditions, such as temperature changes, oxidation and exposure to microbes, which can change their original composition. Food additives play a key role in maintaining the food qualities and characteristics that consumers demand, keeping food safe, wholesome and appealing from farm to fork. Food additives are very carefully regulated and the general criteria for their use is that they perform a useful purpose, are safe and do not mislead the consumer.
3. How is the safety of food additives evaluated in Europe?
All food additives must have a demonstrated useful purpose and undergo a rigorous scientific safety evaluation before they can be approved for use. Until the creation of the European Food Safety Authority (EFSA), the safety evaluation of additives in Europe was done by the Scientific Committee on Food (SCF). At present, it is the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC Panel), who is in charge of this task. At an international level there is a Joint Expert Committee, from the Food and Agriculture Organisation (FAO) and the World Health Organisation (WHO), on Food Additives (JECFA).
Assessments are based on reviews of all available toxicological data in both humans and animal models. From the available data, the maximum level of additive that has no demonstrable toxic effect is determined. This is called the “no-observed-adverse-effect level” (NOAEL) and is used to determine the “Acceptable Daily Intake” (ADI) for each food additive. The ADI provides a large safety margin and is the amount of a food additive that can be consumed daily over a lifetime without any adverse effect on health.
The SCF before and now the European Food Safety Authority, encourage the lowest possible levels of an additive in a food. To ensure people do not exceed the ADI by consuming too much of, or too many products containing a particular additive, EU legislation requires that studies are done to look at the ranges of intakes across a population and to address any changes in consumption patterns. Occasional intakes over the ADI are unlikely to cause any harm because of the 100-fold safety margin. However, if the ADI might be exceeded by particular sectors of the population, the Commission would assess the need to review levels in foods or reduce the range of foods in which the additive is permitted.
The Codex Alimentarius Commission, a joint FAO/WHO activity which develops guidelines for food safety globally, is also drawing up new “General Standards for Food Additives” (GSFA), with the aim of establishing a harmonised, workable and indisputable international standard for world trade. Only those additives that have been evaluated by the JECFA are included.
Thanks to strict regulation and thorough testing, food additives can be considered safe components in our diet that are contributing to the rapid evolution of the food supply in Europe and throughout the world
4. How are food additives regulated in Europe?
A true single market for food products could not exist without harmonised rules for authorisation and conditions for the use of additives. In 1989, the European Community adopted a Framework Directive (89/107/EEC) which set out the criteria by which additives would be assessed and provided for the adoption of three specific technical directives: Directive 94/35/EC on sweeteners; Directive 94/36/EC on colours and Directive 95/2/EC on additives other than sweeteners and colours. These three directives establish the list of additives which could be used (to the exclusion of others), the foods in which they could be used and any maximum levels. The purity required for these additives is laid down in directives defining specific purity criteria.
5. What is an E-number?
An E-number signifies approval of an additive by the EU. To obtain an E-number, the additive must have been fully evaluated for safety by the SCF or the European Food Safety Authority. The E-number system also serves as a simple and convenient way to label permitted additives across the range of languages in the European Union. To see the list of permitted additives with an E-number.
6. Do food additives cause hyperactivity?
In the 1970s, some researchers suggested that changes in diet had coincided with a rise in the number of children with behaviour problems. The idea that food additives, and food colours in particular, could be linked to hyperactivity generated much interest and considerable controversy. Scientific studies have found no association between food additives, including food colours and behavioural problems or hyperactivity. The evidence in the current scientific literature gives no support for the use of elimination diets as a primary therapy for behavioural problems.
7. Can food additives cause allergies or food intolerance reactions?
There has been much public concern that additives cause adverse reactions although careful investigations show that this is often based on misconception rather than on identifiable adverse reactions. Food additives have only rarely been shown to cause true allergic (immunological) reactions. Among the food additives reported to cause adverse reactions are:
Reactions to tartrazine (E 102, a yellow food colour) and carmine (E 120 or red cochinille) have been reported occasionally in sensitive individuals. Symptoms include skin rashes nasal congestion and hives, although the incidence is very low (estimated to be 1-2 persons per 10,000) and very rare. IgE-mediated allergic reactions have been reported for carmine. Tartrazine has also been reported to cause asthma in sensitive individuals although the incidence is extremely low.
One group of additives that can cause problems in sensitive individuals is the sulfiting agents. This group includes several inorganic sulphite additives (E 220-228), including sodium sulphite, potassium bisulphite and metabisulphite containing sulphur dioxide (SO2). These preservatives are used to control microbial growth in fermented beverages and they have been widely used in wines, beers and fruit products for over 2000 years. In sensitive (asthmatic) individuals, sulphites may trigger asthma characterised by breathing difficulties, shortness of breath, wheezing and coughing.
Monosodium glutamate (MSG) and aspartame
MSG is made up of sodium and glutamic acid. Glutamic acid is an amino acid found naturally in high protein foods such as meats and dairy products like Camembert cheese. MSG is also a flavour enhancer used in prepared meals, some Chinese food, certain sauces and soups. MSG has been “blamed” for a variety of side effects including headaches and body tingling, however scientific studies show no link between MSG and these reactions suggesting that some other component of the meal, or even psychological responses, may be responsible for any adverse effects.
Similarly, the high-intensity sweetener aspartame (another substance made from naturally occurring amino acids, aspartic acid and phenylalanine) has been blamed for a wide variety of adverse effects, none of which have been validated by scientific studies.
While food additives pose no problems for most people, a small number of people with specific allergies may be sensitive to certain food additives. It appears that where food additives have an adverse effect, they exacerbate a pre-existing condition rather than induce it. These adverse reactions, which are rarely allergic, and the foods or food components responsible, should be validated by a health professional or dietician to ensure that unnecessary dietary restrictions are not imposed. As all food additives are clearly labelled, those with specific sensitivities and those who believe they have sensitivity to a food additive, can readily avoid any that may pose problems.
8. What food additives are used in Europe?
Food additives that are commonly added to foods in Europe include:
8.1. Additives that maintain freshness and prevent deterioration
Some food additives help to keep foods fresh and safe. They help increase shelf-life by protecting foods against deterioration caused by oxidation or by micro-organisms. They can be divided into two categories based on their principal function.
Antioxidants prevent the oxidation of foods that results rancidity or discoloration. They are used in baked foods, cereals, fats, oils and salad dressings. The major fat soluble antioxidants are:
Tocopherols (E 306-309), BHA (butylated hydroxyanisole or E 320) and BHT (butylated hydroxytoluene or E 321) – these protect edible fats, vegetable oils and salad dressings from turning rancid.
Ascorbic acid (E 300) and citric acid (E 330) – which preserve the colour of freshly cut fruits and vegetables.
Preservatives limit, retard or arrest the growth of micro-organisms (e.g. bacteria, yeast, mould) that are present in or gain entry to the food, preventing spoilage or food poisoning. They are used in baked foods, wine, cheese, cured meats, fruit juices and margarine among others. Examples include:
Sulphur dioxide and sulphites (E 220-228) – these help to prevent colour changes in dried fruits and vegetables. Sulphites also inhibit the growth of bacteria in wine and fermented foods, some snack foods and baked goods. Sulphites also have antioxidant properties.
Calcium propionate (E 282) – prevents bread and baked foods from turning mouldy.
Nitrates and nitrites (sodium and potassium salts) (E 249-252) – are used as a preservative in processed meats such as ham and frankfurters to keep the products safe by preventing the growth of botulinum bacteria, Clostridium botulinum, which is highly pathogenic.
8.2. Additives that amplify or promote sensory qualities
Additives are also useful for imparting certain characteristics to foods, improving texture or helping in food processing.
8.2.1. Taste and texture modifiers
Emulsifiers and stabilisers – The purpose of these food additives is to maintain consistent texture and to prevent the separation of ingredients in such products as margarine, low-fat spreads, ice cream, salad dressings and mayonnaise. Many reduced-fat and low-fat versions of common foods are dependent on this technology. Any recipe that requires the mixing of ingredients that normally do not mix, such as fat and water, need emulsifiers and stabilisers to impart and maintain the desired consistency. Examples include lecithin, mono- and digycerides.
Thickeners – these substances help increase the viscosity of foodstuffs. They are added to foods such as salad dressings and flavoured milk. Gelatin or pectin are often used as thickening agents.
Sweeteners – Both “bulk” and “intense” sweeteners impart a sweet taste to foodstuffs and are useful in low-calorie products and for special dietary products, such as those for diabetics. Intense sweeteners, such as acesulfam K (E 950), aspartame (E 951) and saccharin (E 954) are 130-200 times, 200 times and 300-500 times sweeter, respectively, than sugar-and they have zero calories. Thaumatin (E 957), a naturally sweet protein extracted from the fruit of the plant Thaumatococcus danielli, is 2500 times sweeter than sugar and is used at very low levels for its flavouring properties. Bulk sweeteners include sorbitol (E 420), isomalt (E 953) and maltitol (E 965) and these can be incorporated into “table-top” sweeteners and in energy-reduced foods, in which they provide volume and mouth feel. These substances have reduced caloric value, providing 2.4 kcal/gram compared with 4 kcal/gram for other carbohydrates.
Flavour enhancers – Probably the best known is monosodium glutamate (MSG; E 621), which is used to bring out and enhance the flavours in the foods to which it is added. It is used mainly in savoury products and in a wide variety of oriental dishes.
Others – this group includes acids, acidity regulators (used to control acidity and alkalinity in various types of food products), anti-caking agents (used to keep powders flowing freely), anti-foaming agents (reduce foams, e.g. when jams are boiled), and packaging gases (used in certain types of sealed packages, such as for meat, fish, seafood and ready-prepared vegetables and salads found in chill cabinets).
Colour is one of the first and most important sensory qualities and it helps us to accept or reject particular foods. Whilst adding colour may appear to some to be purely cosmetic, there is no doubt that colour is important in consumer perception of a food and it is often associated with a specific flavour and intensity of flavour. Colours are used to add or restore colour in a food in order to enhance its visual appeal and to match consumer expectations. The processing of peas and the preparation of jams can lead to loss of colour, and hence food colours can compensate for these losses. Some colours are used purely for visual decoration on cakes and confectionery items. Masking or disguising inferior quality, however, are unacceptable uses of colours.
The primary reasons for adding colours to foods include:
To offset colour loss due to exposure to light, air, extremes of temperature, moisture and storage conditions
To compensate for natural or seasonal variations in food raw materials or the effects of processing and storage to meet consumer expectations (Masking or disguising inferior quality, however, are unacceptable uses of colours.).
To enhance colours that occur naturally but at levels weaker than those usually associated with a given food.