Every year, food allergies cause about 30,000 visits to the emergency room and an estimated 150 deaths in the United States. Milk, eggs, peanuts, tree nuts, fish, shellfish, soybeans, and wheat are 8 foods that cause 90% of all allergic food reactions. But why is it that those are the specific foods that cause food allergies while others don’t? A study conducted by a group of university scientists in 2005 suggests that the answer may lie in three-dimensional protein structures.
Our body’s immune system detects and destroys pathogens that could make us sick. A food allergy happens when our immune system overreacts and releases immunoglobulin antibodies to attack a harmless food protein. This releases chemicals that create an allergic reaction. Our immune systems will only react to certain proteins or molecules that refuse to be broken down and stay in our bodies for long periods of time. So, over the years, scientists have been able to deduce the fact that certain protein structures in foods contribute to their allergenicity. They did this by experimenting with all proteins in food allergens and categorizing most of them in just four main common structure groups. Some of these common structures make the proteins very stable in our bodies thus making them hard to digest.
(Picture or structure of Immunoglobulin e)
Clare Mills(leader of a research team at the British Institute of Food and Research) also analyzed surface structures in proteins that were cross-reactive. One family of proteins, the Bet v 1 family, showed an unusual conservation of surface shapes across different foods/plants. Usually, cross-reactive proteins change quite a lot on their surfaces from species to species but this family was unusual to Mills because although some Amino Acid residues changed, the shape of the molecule was relatively the same. From this study, Mills was able to conclude the fact that the degree of change in the surface of the allergenic protein from food to food correlates with the number of foods that cause allergic symptoms in people as well as the degree of allergenicity of the foods. For example, a Bet v 1 related allergen Api g’s surface does not change much. It can be found in celery as well as in birch pollen and so if you develop an allergy towards one of them, you’re most likely going to be allergic to the other as well.
Along with the molecular aspect of the allergen itself, food allergies can also be caused by certain natural risk factors There are four main factors:
- Age: Young children are more likely to develop food allergies than adults
- Family History: Having a parent or sibling with a food allergy increases your risk
- Having a food allergy: People with food allergies tend to have more than one
- Having a related medical condition: Some people develop a cluster of several different allergic diseases because of a medical condition from the past
In conclusion, Food allergies are caused when our immune system reacts to specific proteins in the allergens. The reason that we aren’t allergic to all foods is because only certain foods have proteins with specific structures that make it difficult for our digestive system to break down. If a protein remains in our body too long, our immune system will react to it, causing allergies. Lastly, there are also natural risk factors associated with allergies that cannot be prevented. So, to make sure that you don’t get allergic reactions, your best bet is to just stay away from the foods you know you’re allergic to.