Learning about Food Allergies and the Detection of Allergens

Food allergies have become a growing concern worldwide, as there has been a large increase in the number of both children and adults in the last few decades that are being affected by this immune system condition. The National Institute of Allergy and Infectious Diseases (NIAID) has reported that 4% of adults and 5% of children in the United States are currently affected by food allergies. As it is becoming a more common problem amongst people, it is important to bring awareness and to learn more about food allergies.

Generally, how do allergic reactions work?

Most commonly, the body will detect a foreign invader (an antigen) causing a large immune response. Antibodies or an immunoglobulin (Ig), which are Y-shaped proteins created by the body in response to a particular antigen, are released so that it binds to the antigen and is able to remove it from the body. Antibodies are highly specific proteins made up of two light chains and two heavy chains linked by disulfide bonds. On each side of the Y, an antibody contains a highly variable region made up of amino acids which contain the specificity needed to bind to a particular antigen. When the antibody binds the antigen, a complex is formed that triggers the breakdown and destruction of that antigen.

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Considering that food consumption is a pretty large part of life, why do some people’s bodies react so strongly to certain foods? How does the body recognize food as a threat?

Unfortunately, the reason why this severe immune response occurs in some individuals and not in others is still unknown, but the mechanism of food allergies has been well researched. A food allergy occurs when a person is exposed to a certain food that triggers an unwanted immune reaction. Our immune system is supposed to protect us from foreign invaders that make us sick; however, in some individuals a food that is ingested will contain an antigen that causes a harmful immune response. The most common food allergens include: peanuts, tree nuts, milk, eggs, and soy. The proteins that make up these foods often are the source of the antigens detected in the body. When the food is broken down into proteins and encounters a lymphocyte cell (a white blood cell that is part of the immune system) the food is seen as harmful and causes the production of antibodies called immunoglobulin E (IgE). These antibodies will then bind to IgE binding sites on mast cells, which will circulate the body and come into contact with more food antigen. After some time, the body will become hypersensitive to the antigen, and when the IgE binds another antigen it will cause the mast cell to release things like histamines and leukotrienes, which will cause an allergic reaction. This hypersensitivity is called sensitization. This means that even small traces of the antigen in the body will trigger an allergic reaction from the immune system. 

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Symptoms of allergic reactions can present differently amongst people. In some, the response will be mild causing some skin or stomach irritation. In others, the response can be severe causing swelling and trouble breathing. The most severe response being, anaphylaxis, which is a reaction that can lower blood pressure and can close up airways making it very difficult to breathe.

How can we detect these allergens in food and why is it important? 

In order to detect food allergens, we want to determine the presence of the antigen or antibody of the allergen. This can be accomplished through methods such as immunoblots, enzyme-linked immunosorbent assays (ELISAs), and polymerase chain reaction (PCR). The most common method being ELISAs, because they are a reliable method that are designed to detect specific antigens through antibodies. It is important to be able to detect these allergens quickly, and accurately determine the presence of common allergens in food products so that those with allergies are able to safely avoid these foods.

Interested in learning more about food allergies or the antibody-antigen relationship? Check out the following Edvo-Kits to learn more!