Editorial
Article Type: Editorial From: Nutrition & Food Science, Volume 38, Issue 5.
I have been pleased to put together this special edition of Nutrition and Food Science, which focuses on food allergies and intolerances, which are often called hypersensitive reactions to food. These conditions affect some 1.5-3.5 per cent of adults and 2-8 per cent of children and it is an area of increasing interest in the developed world.
This editorial has been made longer to include key definitions and information on food hypersensitivity.
In requesting papers for this special edition it can be clearly seen that most have been derived from the developed countries such as the UK and USA. There was little response to this request from the developing countries. However, in developing countries there is a wealth of unusual foods, which could be of assistance to those who have a restricted diet due to a food allergy or intolerance. Therefore these papers have been included as well.
I am conscious the area of food allergies and intolerances is a controversial one with some less well established and research methodologies and treatments,which can in some ways, discredit the excellent science that is also performed.
People who have allergies to foods can react to minute quantities of the relevant foodstuff so it is vital that caterers, food manufacturers and anyone involved in food or nutrition has some understanding of this area.
Definitions
Adverse reactions to food can be due to a toxic reaction to a constituent of the food such as aflatoxins from mouldy peanuts causing liver damage or solanine, a toxic compound found in the green parts of potatoes which have been kept too long.
Non-toxic reactions are defined as hypersensitivity and occur in an unpleasant manner (and at times deadly way) each time the food (or component of a food or food additive) is eaten.
There are two forms of hypersensitivity;
- 1.
(1) Food allergy, which involves an abnormal immunological response. This involved the IgE mechanisms and is often severe, immediate and indeed life threatening. Such a life threatening response is termed an anaphylactic shock, which is associated with severe swelling of the airways. In the UK around ten people a year die from such reactions. If the allergic reaction is not IgE mediated it is often a slow onset with a range of symptoms such as eczema, asthma, vomiting and skin reactions. This makes it quite difficult to diagnose. Both types of food allergy are due to proteins found in foods.
- 2.
(2) Non-allergic hypersensitivity, which is often termed a food intolerance and does not involve the immune system. It can be due to a lack of an enzyme such as lactase, which occurs in lactose intolerance, histamine production or a pharmacological response such as may occur to mono sodium glutamate. Thus the food components may not be proteins. While the symptoms are not usually life threatening they are often very unpleasant and difficult to diagnose.
Food implicated in food hypersensitivity reactions
There is a whole range of foods implicated in food allergies and intolerances. Some are quite common components of the diet. Others may be considered more obscure.
There are strict requirements for pre-packaged foods to be labelled with potential allergens. These are
peanuts (which are in fact not a true nut but grow underground on a plant in the same way that potatoes do);
tree nuts like brazils, almonds, etc;
eggs of all types;
milk again of all types;
crustaceans such as crab and lobster;
fish of all types;
sesame;
cereals which contain gluten such as wheat, rye, oats and barley;
soy;
celery;
sulphur dioxide – a preservative;
mustard;
molluscs such as squid and snails; and
lupin which is added in some instances to flour to boost protein levels.
Looking briefly at the specific groups of foods;
Tree nuts like brazils, almonds, etc. and peanuts together with seeds have been particularly implicated in food allergies and anaphylactic shock. People with such sensitivities tend to have the problem persist through out life and have to carefully manage their diet.
Eggs of all types tend to be implicated in a number of disorders particularly in children, but many children do grow out of the disorder by the time they go to school.
Milk again of all types. This is most prevalent in children and the majority grow out of it by school age. Where it does persist some find that different types of milk such as goat or buffalo may be better tolerated. In others there is no tolerance. Some individuals react not to the protein in milk but to the sugar lactose. This is due to a lack of the enzyme lactase. This occurs in certain groups being more common in Chinese populations. In other people the enzyme may be lacking after a severe gastrointestinal disorder but recover in time.
Crustaceans such as crab and lobster, fish of all types and molluscs such as squid and snails cause reactions in some people. It is noted that there is a greater prevalence to these in the USA. Often any hypersensitivity to these foods is combined with that to other foods.
Cereals, which contain gluten such as wheat, rye, oats and barley, can cause a reaction called coeliac disease. This is relatively common in the UK with one in 300 people suffering. It often presents in adults with gastro-intestinal symptoms and resultant deficiencies such as anaemia. Reactions to the wheat itself can also occur in some individuals.
Soy hypersensitivity is not that common and when seen in children are often out grown.
Sulphur dioxide – a preservative can cause problems such as asthma in some individuals. Other additives such as the red and yellow food colours such as tartrazine, sunset yellow, quinoline yellow, carmoisine and ponceau as well as the preservative sodium benzoate have been implicated in behavioural problems in children. For this reason these have been recommended not to be used in children's foods. Monosodium glutamate, a flavour enhancer, used in traditional Chinese cooking and also manufactured products may cause reactions in some individuals with headaches and flushing.
Reactions to less common foods such as mustard, lupin, kiwi fruits, latex(and hence foods packaged in bags which have a latex component) can all be seen in individuals even though they are not common.
Where to obtain information on food hypersensitivity
There is excellent advice available on the whole area of food allergies and intolerances.
The Food Standards Agency produce a range of information on food allergies and intolerances on their website and booklets can also be obtained by post. Of note is “Allergy – what to consider when labelling” which is aimed at small food manufacturers.
The Anaphylaxis Campaign and Allergy UK provide support and information.
Registered dietitians can provide an excellent service on diets for different types of allergies and intolerances. They can be contacted via the British Dietetic Association.
The Migraine Trust, National Eczema Society and Asthma UK produce information on specific disorders.
Coeliac UK produces a wealth of information and are at present promoting a toolkit for caterers to help them cope with gluten free diets. They also produce a magazine called the “Crossed Grain”.
A magazine called Foods Matter aimed at food allergy and intolerance sufferers.
Training on nutrition (including food hypersensitivity) at various levels is provided by the Royal Society for the Promotion of Health and the Royal Institute of Public Health (RIPH). These two organisations are at present in the process of merging. Highfield training produce information on food allergy auditing for the food industry and the RIPH have just launched a qualification on food allergy.
Finally
There seems no conclusive evidence as to why food hypersensitivity is increasing but there are a number of theories around such as those based on the immune system and in this cleaner and more antiseptic society it turns on itself and produces these problems with food.
It is an area where more research is needed both in causes, management and food alternatives.
Mabel Blades
