Food allergy is a very specific and occasionally life-threatening condition that appears to be on the rise across western countries. Appears is the important word here as it is getting increasingly difficult to judge the incidence of food allergy when it is so often confused with food intolerance or recorded only as part of more general allergy statistics.
This article on food allergy is by Kathryn Senior, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.
What is a food allergy?
Food allergy is a specific reaction to large molecules in our food, such as proteins. Food allergy can cause a wide range of symptoms but is only very rarely so serious that it is life-threatening. When food allergy occurs, the immune system stimulated incorrectly to defend the body against the perceived ‘foreign substance’ by producing antibodies called immunoglobin E (IgE). These antibodies trigger inflammation in critical areas of the body, such as the trachea, causing breathing difficulties, or the lips and tongue, again inhibiting breathing and also causing swallowing problems.
In severe cases of food allergy, the body can go into anaphylactic shock, resulting in a sudden and rapid drop in blood pressure. Anaphylaxis can be fatal unless treated swiftly, and people who know they are at risk often carry adrenaline to ensure prompt treatment whatever the circumstances.
Food intolerance is not an allergy
One of the biggest difficulties in deciding whether food allergies are on the increase, is the confusion in public perception between food allergy and the much more common food intolerance. The latter causes a spectrum of symptoms from slight rashes and mild headaches to chronic IBS and severe migraines. Food intolerance is usually set off only by a substantial quantity of the food in question and it is never fatal. Food allergy can be triggered by the smallest trace of the problem substance.
The rapid growth of alternative medicine, in which alleged food intolerances are blamed for all manner of complaints, muddies the waters still further. There are no end of complicated, and usually expensive, ‘allergy tests’ performed each year as people seek a quick fix for their weight gain, lethargy or other lifestyle illnesses.
Up to 8% of children have some form of food allergy, though many will grow out of this in adolescence. The British Dietetic Association estimates that fewer than 3% of adults actually have a food allergy. Other studies put the actual food allergy figure below 2%. It is telling therefore that more than 20% of adults are convinced they are affected by some type of food allergy. In contrast, up to 45% of us suffer some food intolerance at some point in our lives.
How much of a problem is it?
The public may perceive food allergy to be worse than it is but hard evidence is not easy to find. The Institute of Food Research points out the lack of agreement on the exact diagnosis of food allergy makes ‘estimates of its prevalence generally imprecise’.
A typical example of this is can be seen in the data on hospital admissions for anaphylactic shock – one of the most serious symptoms of food allergy. Although hospital admissions rose seven-fold between 1990/01 and 2003/04, and there were around 20 deaths per year, it was unclear how many of these were food allergy related. The Anaphylaxis Campaign has concluded that the number of deaths due to food allergy has often been underestimated due to ‘misdiagnosis or misreporting’.
A rise in incidence or in diagnosis?
For some specific allergies, there is strong data. For example, QResearch reported to the House of Lords that peanut allergy had risen by 117.3% between 2001 and 2005 affecting 25,700 people in England, with one in every 12,420 people newly diagnosed with the condition during 2005. There is also a documented rise in the number of different food allergy types identified in recent years. These include soya, sesame seeds, mustard, chickpea and kiwi fruit. Clearly, as our diet has widened, so new food allergy types have been discovered.
Although some data is high quality, it should not be taken to mean that food allergy is becoming more common. More cases have been detected and diagnosed in the last decade, but that is probably due to greater awareness rather than an increase in the number of people affected.
Once again, precise figures for food allergy alone are difficult to come by, however, the Department of Health estimate that 3 million people consult their GP each year with allergy related illnesses, costing between £200 and £300million. Allergy related drugs cost around £0.9 billion per year, amounting to 11% of the total drugs budget. There are also around 70,000 hospital admissions each year for allergy related asthma and 3,000 for anaphylaxis, together costing over £75 million.
There is an element of ‘fashion’ about food allergy and there has been for several years. The problem with this is that many people think they have food allergy, and go to great lengths to cope with it when they don’t have it at all. This wastes healthcare resources and provides a smokescreen that could prevent a real, serious underlying illness from being detected by either the person concerned or their doctor. Worse still, confusing it with the less serious food intolerances that occur could mean that a true food allergy is not taken seriously enough, leading to some deaths from anaphylactic shock that could be been prevented.