Food allergies are something we’ve all heard of. Whether it is extreme allergic reactions in the news, or simple allergen information on food labels, it’s become a part of daily life. But if you don’t have an allergy yourself, it’s easy to disregard its importance. Food allergy incidences have increased in the last 30 years, some with life threatening circumstances.
What causes a food allergy? The truth is we don’t exactly know for sure and the pathways are extremely complex. Food allergy is a type of food intolerance. Food intolerances can be caused by enzymes, such as lactose intolerance, or by antibodies. Only reactions involving the Immunoglobulin E (IgE) antibody are classified as food allergies; reactions involving other enzymes are intolerances.
When someone eats a food that they have an allergy to, their immune system produces IgE. IgE causes the cells to go through a series of processes that result in the release of histamine. Histamine causes the ‘allergic reaction’ symptoms. A mild reaction can result in swelling and hives, whilst the most severe reactions can result in trouble breathing and anaphylactic shock. It is estimated that 6 to 8 people in the UK die from an allergic reaction to food each year. However, this number is hard to analyse, so could be much higher.
There are 14 ‘common’ allergens that must be labelled on all food sold. These are: cereals containing gluten, crustaceans, eggs, fish, peanuts, tree nuts, soybeans, milk, mustard, celery, sesame, sulphur, lupin and molluscs. Around 95% of all food allergies are caused by these. Allergy incidence in children is much higher than in adults, meaning a lot of children ‘grow out’ of their allergies.
There have been many theories for why allergy incidence is increasing. Theories suggest it could be due to children growing up in cleaner environments, meaning they are exposed to less allergens from birth – this is known as the hygiene hypothesis. It is also considered that the lifestyles of the western world contribute to incidence. Allergy is increased from the food we eat and from being surrounded by high pollution, backed up by evidence developing countries having far lower allergy rates. There is also a suggestion that the growing rates of vitamin D deficiency in the UK are to blame. Scientists have not yet been able to pin down an exact source.
There’s no doubt that recorded cases of allergy are increasing. In reality, less than 1% of adults have a food allergy. However, 20-30% of adults believe they have some kind of food allergy. This could be caused by the heightened awareness of food allergy and the difficulties in determining the difference between allergy and intolerance, however. There is also a lot to be said for the money that can be made by the health food market surrounding allergy and intolerances. A 2018 study showed that on average, free from items cost 159% more than their original counterparts. The ethics around convincing a nation they are allergic to certain foods are highly questionable, but certainly profitable.
If you think you may have an allergy, contact your GP for an allergy assessment. Although convenient, many at-home allergy tests are not reliable and could end up restricting your diet unnecessarily.
Lizzie studied Food Science and Nutrition at the University of Leeds and is currently working in product development with one of the UK's largest snack manufacturers. Her passion for science extended to teaching whilst studying science education modules at university. She believes science should be more accessible and interesting to everyone.