What Causes Food Allergies?

What causes food allergies

Food allergies can cause a range of reactions from vomiting to anaphylaxis but what causes food allergies to develop?

Food Allergies vs. Food Sensitivity

Reactions caused by food allergies can be much more severe than a food intolerance or food sensitivity. Food allergies are the immune system treating a specific protein in a food as harmful and responding by producing IgE (Immunoglobulin E) antibodies that attack this protein.  Food sensitivities and intolerances are your body not properly digesting a food and do not affect your immune system, resulting in stomach upset, diarrhea and vomiting.

Common food allergens include egg, milk, wheat, peanut, tree nut, shellfish, fish, soy, mustard and sulphite.  Common food sensitivities can be gluten, dairy (lactose), caffeine and fructose.

What Causes Food Allergies?

When you come in contact with a food that threatens your immune system, the immune system reacts immediately by releasing histamine and other chemicals into the bloodstream.  Histamine causes blood vessels to expand and the skin to become inflamed or swollen. It also affects the nerves, hence the itchy rash and hives often experienced.  The nose may produce more mucus resulting in itchy, runny nose and sneezing. 

Family History

Food allergies can be hereditary. If close family members have any allergy related issue such as asthma, eczema, food or environmental allergies, you can have a higher risk of developing allergies also. 

Other Allergy Conditions

Having one allergy related issue – such as asthma – can lead to having food allergies develop.1 

Early Exposure

For decades doctors and researchers thought early exposure could actually create a higher risk of developing an allergy in children, but studies are now showing the opposite. 

Maria Garcia-Lloret, MD, a professor of pediatric allergy and immunology and co-director of the UCLA food allergy clinic says "we now believe peanuts, which are not actually nuts but are legumes, should be given to babies as early as 4 months, when solids are first introduced. It should not be the very first food a parent gives...However -- and this is critical -- babies with eczema and other established food allergies are considered high-risk. For those kids, introduction to peanuts should be carefully monitored under the guidance of a pediatrician."2

Change in Diet

There are some theories that the increase in the number of people with food allergies is due to our change in diet and environment t over the decades. Eating more or less meat that alters fat intake, eating less fruits and vegetables prevents getting enough benefits from antioxidants, less natural vitamin D due geographical location and longer winters and our hyper vigilance avoiding germs and increased use of antibacterial products.


Although there are not enough studies or long term effects to know what causes food allergies, one thing is constant, when a food allergy is recognized, early treatment and prevention of reoccurrence is key.  Food elimination diets, reading every food label before consuming anything and having antihistamines and epinephrine on hand become life savers when food allergies are a part of your life.



1. WebMD https://www.webmd.com/allergies/chronic-allergies-causes

2. WebMD - https://www.webmd.com/allergies/features/food-allergies-early-exposure

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