Food allergy and food intolerance – what’s the difference? You hear people all the time say they can’t eat a particular food because they are allergic. However, a true food allergy is not as common as you may think. In fact, the adverse reactions to food that are commonly thought to be an allergic reaction are quite often due to food intolerance rather than an allergy.
Food allergy
Food allergy is when a person’s immune system produces antibodies to a particular food protein that it believes is harmful. When an individual eats that food, their immune system releases chemicals, including histamine, in order to protect the body. Some of the most common allergic reactions include eczema, asthma and hay fever, and, in severe cases, anaphylactic shock.
Although research is being conducted into food allergies and new treatments, at present, total avoidance of the problem food is the only way to prevent a reaction.
A food allergy is usually first identified as a problem for infants, toddlers and young children. While children are often allergic to two or three (sometimes even more) different foods, fortunately, most tend to grow out of some allergies, particularly egg and milk reactions, by school age.
Diagnosing a food allergy
Unfortunately, most of the methods used to diagnose allergies are not supported by scientific evidence, so are considered unreliable. Some of these diagnostic tests and treatments include kinesiology, blood testing, iridology, hair analysis, acupuncture and reflexology.
For a firm diagnosis of a food allergy, an immunologist needs to conduct a skin prick test or a blood test to detect if someone has antibodies to the common food allergens.
What is anaphylactic shock?
An anaphylactic reaction is a severe, rapidly progressive allergic reaction that can be life-threatening unless treated immediately. Symptoms can begin within minutes of exposure with hives and swelling of the mouth and throat area, vomiting, diarrhoea, asthma, difficulty breathing and even loss of consciousness. People with severe food allergies need to be very careful as even a trace amount of the problem food can cause a reaction in some individuals.
Food intolerance
Unlike food allergy, food intolerance causes an adverse reaction to a food, but it does not involve the person’s immune system. Rather, the symptoms of food intolerance are triggered by chemicals in food.
The symptoms of food intolerance are varied and can often be very similar to those of a milder food allergy, which is why some people may report they have a food allergy when, in reality, it is far more likely to be food intolerance. People with food intolerance may suffer from symptoms such as hives, skin swellings, eczema, bowel irritation and stomach pains, headaches, fatigue, irritability, muscular aches and pains, poor concentration.
People may be born reacting to certain chemicals, or the intolerances can develop in later life, usually triggered by environmental factors, such as a change in diet or illness.
Identifying food intolerance
Intolerances to food chemicals can only be identified by an elimination diet and challenge procedure, usually best conducted under the supervision of an Accredited Practising Dietitian (APD), as initially, the diet is quite restrictive (and bland in flavour as foods high in food chemicals tend to be the most tasty!). The elimination diet involves following a low-chemical eating plan for three or four weeks and then “challenging” with carefully selected foods, one by one, to identify the chemicals that cause the symptoms.
Once identified, problem food chemicals, such as food additives and artificial colours and flavours, can be avoided by checking food labels and staying away from foods that contain these chemicals.
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