Because the symptoms of many common food allergies may dovetail with the symptoms of different forms of gluten intolerance, this lesson covers the 8 most common food allergies. After this lesson you should feel more empowered to discuss the triggers and treatments of these common food allergies with your doctor.
- What Defines A Food Allergy?
- Introducing the 8 Most Common Food Allergies
- Tree nuts
- Review: What You Need to Know
- Take The Quiz
What Defines A Food Allergy?
Your body’s humoral immune system produces antibodies or immunoglobulins. These immunoglobulins are proteins that can identify and neutralize foreign intruders like bacteria, viruses and toxins. Sometimes these immunoglubulins identify otherwise harmless foreign bodies as harmful and tag them for an immune response.
A particular immunoglobulin, immunoglobulin E (often abbreviated as IgE) may tag food proteins as antigens, triggering your immune system to over-react to them. The cells activated when IgE tags these proteins as antigens are called mast cells and basophils. When these cells are activated, they create an inflammatory response and chemicals such as histamine are released into your bloodstream. The entire process is called an IgE-mediated response to food.
This can result in digestive or respiratory distress as well as dermatitis (a skin inflammation). While allergic reactions can vary in severity, in their most severe form (anaphylaxis) they can be life threatening. After antigen exposure they may quickly grow severe.
This reaction is a type 1 hypersensitivity and is not the same as a food intolerance. For example, a lactose intolerance is not an allergic reaction. In lactose intolerance, your body simply doesn’t produce the right enzyme to digest lactose, so the lactose ferments in your gut and your body doesn’t absorb it into your bloodstream. Many food intolerances are likes this: they don’t involve the immune system; they instead represent your body’s inability to properly digest them.
Because many confuse a food intolerance with a food allergy, the public perception is that food allergies are more common than they are. About 6% of children under 5 have a food allergy about 4% of teens and adults suffer from a food allergy. But this doesn’t include food intolerance or autoimmune diseases.
Food allergies in children often fade as they age. This leads many people to think celiac disease in children will go away as they grow into adults, unfortunately this isn’t the case. As I discuss elsewhere in the Gluten Intolerance School, celiac disease is not a food allergy.
So in short, a food allergy exists when your body produces IgE in response to eating a particular food protein. This IgE tags this food protein as an antigen, which then activates mast cells and basophils, which then results in an inflammatory response.
Introducing the Eight Most Common Food Allergies
To start, let’s just list them. These are sometimes referred to as the “Big 8” and some research suggests they are responsible for up to 90% of all food allergy reactions:
- Shellfish (crab, lobster, shrimp)
- Tree nuts (almonds, cashews, walnuts)
In the United States, some recent evidence suggests a sesame allergy may eventually makes this list as well.
The following is an overview of each of these allergies and isn’t intended to be a comprehensive resource for any single allergy.
All these allergies have the potential to cause eczema, allergic conjunctivitis (red, itchy eyes) and angioedema (lip, tongue or face swelling). Gastrointestinal reactions and anaphylaxis are also possible in all these allergies, but allergies to peanuts and tree nuts often trigger the most severe reactions.
Eggs are the second most common food allergy in children, occurring in approximately 1.5% of all children under 6. However, around 80% of all children will outgrow their egg allergy by age six. Vaccines and anesthetics may contain eggs or be sourced from eggs, so if you’re child tests positive for an egg allergy, make sure your doctor is aware of this when it comes to surgery or vaccinations.
Fish allergies are more common in adults than children. Once they develop, they can be serious and lifelong. Some people are only allergic to certain species of fish, but because of a cross-reactive protein in all fish, people allergic to one fish species are advised to avoid all fish.
Keep in mind that fish makes it into some foods you may not realize, like Caesar salad dressing, Worcestershire sauce, and kosher gelatin. Many omega-3 oil supplements are made with fish oil, but there are excellent vegan alternatives such as flaxseed oil or Ovega-3 algal oil.
Milk is the most common food allergy in children. About 2.5 percent of all children in the United States suffer from an allergy to cow’s milk. However, current research suggests that most (but not all!) children will outgrow their milk allergy before they turn ten. Milk is not currently considered a major allergen for adults.
Note that a lactose intolerance is not a milk allergy. A child with a milk allergy cannot consume lactose-free milk or milk with added lactase.
An allergy to peanuts is the third most common among children and second most common among adults. Recent research suggests peanut allergies are becoming more common among children. Most people with peanut allergies will endure them for their entire lives, although a small percentage of children outgrow them.
Peanut allergy reactions are often immediate and severe. More people with a peanut allergy will suffer from anaphylaxis than any of the other most common food allergies. If you know someone with a peanut allergy, don’t take what you might perceive as “paranoia” lightly. People with a peanut allergy often need to carry an EpiPen (epinephrine auto-injector) to help them avoid anaphylactic shock after an unexpected peanut exposure.
Peanuts, peanut oil and peanut butter can hide in many unexpected foods. Peanut oil is often used in Chinese cooking and in deep-frying. Some skin care products (including makeup) also use peanut oil, so be sure to keep an eye on labels.
Peanuts are a legume, not a nut, but some cross-reactivity has been observed with tree nuts, in particular with hazelnuts and almonds. Also, some people with a peanut allergy also have an allergy to other legumes, the most common being chickpeas, lentils and soy.
An allergy to shellfish is the most common adult food allergy. It is far less common in children. While around 2% of all adults suffer from a shellfish allergy, only 0.1% of all children are allergic to shellfish. While this allergy tends to develop later in life, it can be severe and once it develops, it usually becomes a lifelong matter.
There are two classes of shellfish: crustaceans and mollusks. While some people are allergic to one class and not the other, many people suffer an allergy to both. Only complete allergy testing can isolate your specific condition. Shellfish-sourced ingredients may hide in fertilizer, pet food and vitamins.
Shellfish is the most well-known trigger of Exercise-induced anaphylaxis, a severe allergic reaction that occurs when you combine exercise with a food allergen.
Soy has become a little controversial in recent years because of its phytic acid (phytate) and its phytoestrogenic properties, but for this lesson I am focusing on its well-established conventional understanding as an allergen.
About 0.4% of children suffer from an allergy to soy. Some babies may develop Food Protein Induced Enterocolitis Syndrome, a Milk-Soy Protein Intolerance. Many of these children outgrow this allergy by adolescence, so soy is not considered a major allergen for adults. However, because soy is so pervasive in our food supply, allergic reactions to soy occur more often than allergic reactions to more common food allergens.
Soy has become a ubiquitous ingredient in packaged foods. But it is also sometimes used for Vitamin E supplements, so if you are allergic to soy, check your vitamin labels.
While most soy-based ingredients must, by law in the United States, be identified clearly on food labels, soy lecithin and refined soybean oil are exempted. This is because these ingredients are considered to be so heavily processed their soy protein content is considered negligible.
However, some highly sensitive individuals may still react to these hidden ingredients, so learning to contact manufacturers for detailed ingredient information may become necessary.
While the current data suggests that slightly more than 1% of all children suffer from an allergy to tree nuts, there is also some evidence this frequency may be increasing. While some children will outgrow this allergy by adolescence, for most individuals it remains a lifelong allergy.
Like with peanuts, there is a greater chance of deadly anaphylaxis with a tree nut allergy than there is with most other food allergies.
One of the biggest challenges to understanding and treating a tree nut allergy is grasping the enormous list of tree nuts, including (but not limited to) common nuts like almonds, brazil nuts, cashews, hazelnuts, pecans, pistachios and walnuts. Often times people suffer from an allergy to just one tree nut, but having an allergy to one tree nut greatly increases the likelihood of experiencing an allergy reaction to another tree nut.
People with tree nut allergies also have a greater chance of having an allergy to peanuts.
A wheat allergy is not celiac disease, but it can be just as troubling to some people. Anaphylactic shock is possible, and wheat has been related to exercise-induced anaphylaxis (a severe allergic reaction that occurs when exercise and a food allergen are combined).
While it may not be as difficult to avoid as gluten, wheat is still a pervasive ingredient in our food supply. Some manufacturers use it for thickening sauces and some use it to keep products from clumping within the package (for example, dried fruits are sometimes lightly powdered with wheat flour to prevent clumping).
Read more about a wheat allergy in the lesson on Wheat Allergy Symptoms.
Review: What You Need to Know
If you believe you have one of these food allergies, it is important you consult an allergy specialist for proper testing. You need to isolate your exact allergy and discover any possible related allergies (having one allergy can put you at greater risk of having another).
Because the symptoms of these different food allergies can be very similar and because of the possibility of anaphylactic shock, you shouldn’t diagnose yourself. Have an allergy specialist isolate and identify your exact allergy.
A wheat allergy is not celiac disease and a food allergy is not an autoimmune disease. The way the human body reacts to a food allergen is not the same as the way the body behaves when you have an autoimmune disease.
Remember the list of the most common food allergies — eggs, fish, milk, peanuts, shellfish, soy, tree nuts and wheat. Be vigilant if you have one of these allergies, and be patient and respectful of anyone else who must be vigilant with one of these allergies.
Take the Quiz!
Test Your Understanding of Food Allergies
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