A food allergy results in an abnormal response of the immune system as it over reacts to a normally harmless piece of food. The body sees the food as an invader, releasing chemicals such as histamines in order to fight off the ‘foreign’ object.
Unlike allergies, a food intolerance is in no way linked to the immune system. A food intolerance is usually caused by a digestive problem, as the gut is unable to digest certain foods properly. Particular foods may irritate the digestive system or the individual affected may lack a certain enzyme necessary for successful digestion of the food.
Allergies usually produce symptoms such as dizziness, fainting, tingling of the skin (particularly around the mouth), hives, swelling and nausea. Allergies can cause severe and immediate problems and may be fatal. For this reason they are particularly concerning and ways to deal with allergic reactions must be put in place if possible.
Intolerances are not usually serious or life threatening, but may result in extremely uncomfortable reactions including cramping, diarrhea and nausea.
As food allergies can be extremely dangerous, once an allergy is identified, all traces of that food must be eliminated from the diet in order to avoid potentially fatal reactions. Even touching or inhaling a very small amount of the food may result in a serious allergic reaction. However, food intolerances may be managed without total elimination. Those who suffer from food intolerances can normally ingest a small amount of the food without problem.
Most often, people will recognise a food allergy after suffering a reaction from eating or touching an offending food. Consultation from a medical professional should always follow after the reaction. Blood tests may be taken to measure the level of antibodies in the blood. An abnormal level of antibodies in the blood indicates an allergy to a food. A skin test may also be used to recognise allergies. This test consists of a number of pricks to the skin. These pricked areas are then exposed to tiny amounts of the food(s) in question. Following this, swelling or redness will most likely indicate an allergy to the food causing the reaction.
A food intolerance may be recognised after a period of feeling generally unwell. Cramping, diarrhea and nausea for a prolonged period may indicate a food intolerance. In this case, the best way to test for a food intolerance is to begin an elimination diet. Specific foods are eliminated from the diet and reintroduced slowly.
In this way, it is much easier to identify the food(s) causing the problem. Keeping a food and symptoms diary will be of great help in identifying troublesome foods. Tests for food intolerances are not very reliable, however, suspected fructose or lactose intolerant sufferers may be tested through a breath test. This tests the hydrogen levels in the breath. The breath of lactose intolerants may have higher hydrogen levels than non sufferers.
While individuals may be allergic or intolerant to many different foods, there are some foods that commonly cause allergic reactions and intolerances.
A large proportion of severe allergic reaction are caused by only eight foods. These foods are wheat, milk, eggs, fish, shellfish, peanuts, tree nuts (almonds, cashews, walnuts), and soy. Care must be taken when first introducing these foods into your child’s diet, as an allergy is always a possibility. Common food intolerances include lactose intolerance, gluten intolerance, MSG intolerance, sulfite sensitivity and alcohol intolerance.
According to the European Academy of Allergy and Clinical Immunology (EAACI) more than 17 million people in Europe are affected by food allergies, with 3.5 million of these younger than 25. However, allergies are much less common than food intolerances, with approximately 5% of children and 3% of adults affected by food allergies. Often children will grow out of allergies as they get older, or they may develop new allergies as adults.
Most people are likely to be affected by a food intolerance at some stage in their life. The intolerance may continue for some time and then disappear or may have a more prolonged effect.
For more on food allergies and how to cope with cooking for kids with allergies, click here. Alternatively, visit our Health and Wellbeing page for more food and health resources.