What is food sensitivity?
Food sensitivity is sensitivity to the ingredients in food. In food allergy the body’s immune system is activated against the proteins from food, which are interpreted by the body as “dangerous” intruders. Even small traces of the food to which the individual is intolerant can be sufficient to trigger an allergic reaction. The reactions usually occur rapidly after ingestion of the foodstuffs and in some cases can be serious.
In other types of food sensitivity the immune system is not involved but the symptoms may be similar to those suffered in allergic reactions. The onset of symptoms is less rapid; they are less serious and are dependent on the quantity of food eaten. The term intolerance is often used to describe conditions whereby a food reaction is observed, without this being demonstrated in laboratory tests. There are many forms of food sensitivity or food intolerance – as it is often described.
Lactose intolerance: The gut mucosa has reduced ability to break down milk sugar (lactose in milk and milk products). Causes stomach pain, bloating and diarrhoea, which are not dangerous but are uncomfortable. See fact sheet on milk allergy.
Coeliac: Is a disease of the small bowel, which is often termed gluten intolerance because the gluten proteins in barley, rye and wheat destroy the gut wall. A lifelong gluten-free diet is necessary in order to maintain control of the disease.
Common forms of food intolerance:
In small children, allergies to milk, egg, fish, nuts, shellfish and pulses (peas, peanuts, beans, soya, lupin and lentils) are most common. Children with atopic eczema may in particular have non-allergic sensitivity reactions to citrus fruits, strawberries and tomatoes. These reactions depend on the quantity of the substance taken and most commonly lead to itching and flare-up of the eczema.
In older children and adults, allergies to nuts (peanuts, hazelnuts and almonds), raw carrot, apples, pears and other stone fruits and shellfish are the most common. Lactose intolerance generally has a gradual onset, beginning after the child has finished breastfeeding, up to school-age.
Wheatmeal allergy, with reaction to wheatmeal, is not common but can cause serious reactions and often in connection with exertion. Coeliac disease occurs at a frequency of approaching 1% of the population and can debut at all ages, including in adults. Reactions to additives occur, most commonly in the form of non-allergic sensitivity, and cause mild symptoms.
Symptoms:
Reactions can vary from mild symptoms, which resolve after a short period, to serious, and sometimes life-threatening, symptoms. Itching in the mouth and throat and swelling of the mucosa are termed oral allergy syndrome and are typical in cross reactions to foods, such as experienced by individuals with pollen allergy. Typical gut and stomach symptoms are bloated stomach, pain, diarrhoea and nausea. Skin symptoms such as urticaria, exacerbation of eczema and itching are also common, particularly in small children. Allergic shock (anaphylaxis) is rare, but extremely serious and requires urgent treatment. It is characterised by swelling of the throat, breathing problems, often vomiting, and can progress to a drop in blood pressure and unconsciousness.
How is it diagnosed?
Skin prick test and blood sampling are the most common tests. These alone are insufficient to make the diagnosis but must in the majority of cases be combined with food tests in order to confirm diagnosis. It is essential that important foods are not removed from the diet without a clear diagnosis. This applies in particular to suspected coeliac disease where the diagnosis is almost impossible to make after commencing a gluten free diet. In a trial phase the suspected foodstuffs can be withdrawn for a period of time, thereafter to be introduced on an individual basis.
Accurate testing is available for the diagnosis of coeliac disease and lactose intolerance. There are no collective tests in conventional medicine to establish general food sensitivity. Many alternative therapists offer such tests, but there is no evidence that these do what they promise.
Voksentoppen Barneklinikken, Rikshospitalet HF, is a special hospital for children with allergies. There are no such special institutions for adults. Adults first make contact with their general practitioner who thereafter refers them to an appropriate specialist, e.g. a gastroenterologist, pulmonary physician or Ear, Eye, Nose and Throat (ENT) specialist.
Treatment:
A properly balanced diet is very important and particularly so during childhood. The only treatment in food allergy is to avoid the foods to which one is intolerant. Nutrients in foods removed from the diet must be replaced. In the case of milk allergy it is important to ensure sufficient intake of calcium and B-vitamins. For the smallest children is it also important to ensure that they receive sufficient intake of fats and proteins. Children with cow’s milk allergy should receive a satisfactory milk substitute (on prescription from the pharmacist). In a wheat-free diet it is important to ensure that the diet contains sufficient protein, fibre and minerals. Intake of vitamin C can be low in instances where a number of fruits and vegetables are removed from the diet. The doctor may make a referral to a clinical at the hospital’s outpatients department for individual dietary guidance.
Medication:
Individuals who are vulnerable to suffering serious life-threatening allergic reactions should be provided with an adrenaline syringe (EpiPen and EpiPen Jr.). The syringe contents are injected as an “antidote” in cases where an individual inadvertently ingests something to which he/she is allergic. Allergy medicines taken for other allergic conditions, e.g. pollen allergy, may also reduce the symptoms occurring with ingestion of non-tolerated foods. It is not however usual to take regular medication for food allergies.
The food allergy register
In the event of serious reactions to food, notification should be sent to the Food Allergy Register at the Norwegian Institute of Public Health. The criteria for reporting of incidences are that the patient has attended his/her doctor within 24 hours of eating the foodstuff. The Register was created in order to gain further knowledge about food reactions, including their severity, what foods are reacted to and who is affected.
Often individuals with food allergies must prepare most of their food themselves. When ready-made food is used, it is important to always read the list of ingredients carefully. When visiting restaurants or eating out, it is important to ask about the contents of the food and inform the person(s) concerned about the allergy or food sensitivity.
Prevalence:
Amongst the smallest children – from one to three years – 5-8% have reactions to food. In the remaining population, approximately 5% have food allergy/intolerance – where pollen-related cross-allergies are included. Many more are affected day-to-day, where the problem has practical consequences for family and friends.