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Food Allergies and Your Immune System

Updated on June 09, 2020

Article written by
Kelly Crumrin

KEY TAKEAWAYS:
  • Food allergies are widespread and becoming more prevalent.
  • Food allegies are caused by the immune system overreacting to certain proteins in some foods.
  • Anaphylaxis is a severe and potentially fatal allergic reaction that can be caused by food allergens.
  • There is no cure for food allergy.
  • Avoiding food allergens is the best way to prevent allergic reactions, but it's difficult to do in everyday life. Food allergens are hard to identify, so education, research, and vigilance are key.
  • Immunotherapy is a potential way to treat food allergies that may help some people with severe food allergies prevent life-threatening allergic reactions.

Who Has Food Allergies?

From peanuts to shellfish, 32 million people in the United States (and 17 million people in Europe) have food allergies. Food allergies are becoming more prevalent in both the U.S. and Europe, and hospitalizations from allergic reactions are on the rise.1,2

Food allergies are more common in young people. In the U.S., about 8 percent of children and about 4 percent of adults have been diagnosed with at least one food allergy.3,4 Teenagers and young adults have the highest risk for a fatal allergic reaction from food.5

Why Do Some People Develop Food Allergies?

It is largely a mystery why some people develop food allergies, but both genetic and environmental factors seem to play a role.6 Having family members with food allergies or related allergic conditions, such as asthma, eczema, and environmental allergies raises your risk for developing food allergies. Children who had eczema as babies are more likely to later develop food allergies.7 Growing up with siblings, pets, or livestock seems to lower the risk for developing food allergies.6

The Immune System

Your immune system is designed to defend your body. It spots and neutralizes dangerous invaders such as bacteria, viruses, and parasites.8 When you develop a food allergy, your immune system sees a specific food protein as a threat and becomes hypersensitive to it. Any protein that triggers an allergic reaction is called an allergen.

The first time the immune system encounters the food allergen and misidentifies it as a danger, white blood cells begin producing allergic antibodies. When you are exposed to the food allergen again, the antibodies trigger immune cells to release mediators that cause allergy symptoms such as breathing difficulties, hives, or vomiting.8,9

Symptoms of Food Allergies

Food allergies can cause widespread symptoms that affect many different systems of your body. The severity of food allergy symptoms can range from mild to life-threatening. The same person may experience different symptoms - at varying levels of severity - over time. Some symptoms of food allergy include:10

Anaphylaxis is the most severe form of allergic reaction.11 During anaphylaxis, people experience two or more of the symptoms listed above (affecting more than one body system) and may also experience:

Anaphylaxis is a medical emergency, and it can be fatal if not treated immediately with an injection of epinephrine followed by a hospital visit.12

Is It Food Allergy or Food Intolerance?

It can be difficult to tell the difference between a food allergy and a food intolerance because they can cause some of the same symptoms such as nausea, diarrhea, and vomiting.13 Unlike a food allergy, a food intolerance does not involve the immune system reacting to a food protein. Food intolerances usually occur when the body has trouble digesting a food. For instance, people with lactose intolerance cannot digest lactose, a type of sugar found in most milk products. Other people cannot digest gluten. Unlike food allergies, food intolerances tend to cause symptoms that are limited to the digestive system, and do not cause life-threatening reactions such as anaphylaxis.14 People with food intolerances may not experience symptoms if they eat small quantities of the food, whereas people with food allergies have the potential to develop intense reactions if they are exposed to even small amounts of the allergen. If you have food allergies, your best course of action is to avoid foods to which you are allergic.

How Do Food Allergies Differ From Environmental Allergies?

Allergies to proteins in the environment - such as those in dust, pollen, animal dander, or mold - are known as environmental allergies.15 Environmental allergies, which are often seasonal, commonly cause bothersome “hay fever” symptoms such as sneezing, watering eyes, and a runny nose. Environmental allergies are a nuisance, but most cannot cause anaphylaxis. In contrast, an allergy to bee sting venom can result in a life-threatening reaction. In many people, symptoms of environmental allergies can be treated with over-the-counter antihistamines such as Benadryl® (Diphenhydramine), Claritin® (Loratadine), or Zyrtec® (Cetirizine). People with food allergies and bee sting allergy are at risk for more dangerous reactions and therefore must carry epinephrine auto-injectors.

[CHART: Environmental vs. Food allergies (AIMMUNE)]

Which Foods Cause Allergic Reactions?

It is possible to have an allergic reaction to the proteins in any food. However, some foods are much more common allergens than others.

In the U.S., 90 percent of allergic reactions are accounted for by eight food allergens that are legally required to be listed on food product labels.16 Currently, the eight major allergens in the U.S. are:

Sesame is being reviewed by U.S. Food and Drug Administration (FDA) and may soon be added as the ninth food allergen to require mandatory labelling.17

The European Union mandates labelling of these 14 major allergens on food products sold in member countries:18

How Are Food Allergies Treated?

So far, there is no cure or approved treatments for people with food allergies.19 Avoiding allergenic foods is the only way to reduce or eliminate the risk for food allergy symptoms and anaphylaxis. However, it can be difficult to avoid exposure to all traces of allergens.

Sometimes, mild to moderate food allergy symptoms such as itching, sneezing, or hives may be managed with antihistamines.20 Injection with epinephrine is the only emergency rescue treatment that works to reverse life-threatening anaphylaxis.21

When considering treatment options for food allergies, it is important to work with a board-certified allergist.

What Is Immunotherapy?

Immunotherapy is an approach to treating and managing food allergies that involves controlled, gradual exposure to a food allergen over time.22 The goal of immunotherapy is to desensitize the immune system to the food allergen, making accidental exposures less dangerous for those with severe allergies to foods.

In oral immunotherapy (OIT), tiny amounts of the allergen are ingested under supervision of an allergist. In epicutaneous immunotherapy (EPIT), a patch containing the food allergen is worn on the skin. In both approaches, the dosage of the allergen is increased over time. Since immunotherapy involves exposure to allergens, it is performed under a doctor’s supervision.

Other forms of immunotherapy taken sublingually (under the tongue) or injected subcutaneously are available for other types of allergies such as grass pollens, ragweed, and bee venom.

No immunotherapy regimens for food allergies have been approved by the U.S. Food and Drug Administration for use by the public at this time. However, several clinical trials have shown that immunotherapy can potentially lessen the immune response to small amounts of food allergens in children with severe allergies.23 More trials are underway, and many researchers believe immunotherapy could prove to be a valuable treatment strategy for many people with dangerous food allergies.

Sources

1. Facts and Statistics. FARE. https://www.foodallergy.org/life-with-food-allergies/food-allergy-101/facts-and-statistics. Accessed February 2019.

2. Food Allergy: a burden carried by more than 17 million Europeans. Anaphylaxis Campaign. https://www.anaphylaxis.org.uk/2015/07/20/food-allergy-a-burden-carried-by-more-than-17-million-europeans/. Accessed February 2019.

3. Food Allergy: Overview. American College of Allergy, Asthma & Immunology. https://acaai.org/allergies/types/food-allergy. Accessed February 2019.

4. Approximately 8 Percent of Children are Diagnosed with Food Allergies. American Academy of Pediatrics.https://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/Approximately-8-Percent-of-Children-are-Diagnosed-with-Food-Allergies.aspx. Accessed February 2019.

5. Facts and Statistics. FARE. https://www.foodallergy.org/life-with-food-allergies/food-allergy-101/facts-and-statistics. Accessed February 2019.

6. What Causes Food Allergies? FARE. https://www.foodallergy.org/life-with-food-allergies/food-allergy-101/what-causes-food-allergies. Accessed February 2019.

7. Childhood Food Allergy. Allergy UK. https://www.allergyuk.org/information-and-advice/conditions-and-symptoms/42-childhood-food-allergy. Accessed February 2019.

8. Allergies and the Immune System. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/healthlibrary/conditions/allergy_and_asthma/allergies_and_the_immune_system_85,P00039. Accessed February 2019.

9. Allergy. British Society for Immunology. https://www.immunology.org/policy-and-public-affairs/briefings-and-position-statements/allergy. Accessed February 2019.

10. Symptoms of an Allergic Reaction. FARE. https://www.foodallergy.org/life-with-food-allergies/food-allergy-101/symptoms-of-an-allergic-reaction-to-food. Accessed February 2019.

11. Signs and Symptoms. Anaphylaxis Campaign. https://www.anaphylaxis.org.uk/what-is-anaphylaxis/patient-signs-and-symptoms/. Accessed February 2019.

12. Anaphylaxis. American College of Allergy, Asthma & Immunology. https://acaai.org/allergies/anaphylaxis. Accessed February 2019.

13. Food allergy vs. food intolerance: What's the difference?. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/food-allergy/expert-answers/food-allergy/faq-20058538. Accessed February 2019.

14. Food intolerance. Anaphylaxis Campaign. https://www.anaphylaxis.org.uk/knowledgebase/food-intolerance/. Accessed February 2019.

15. Allergy. KidsHealth. https://www.kidshealth.org.nz/allergy. Accessed February 2019.

16. Food Allergies: What You Need to Know. U.S. Food and Drug Administration. https://www.fda.gov/Food/ResourcesForYou/Consumers/ucm079311.htm. Accessed February 2019.

17. Statement from FDA Commissioner Scott Gottlieb, M.D., on the FDA’s new consideration of labeling for sesame allergies. U.S. Food and Drug Administration. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm624484.htm. Accessed February 2019.

18. Rules and legislation. Food Standards Agency. https://allergytraining.food.gov.uk/english/rules-and-legislation/. Accessed February 2019.

19. Treatment for Living With Food Allergy. National Institute of Allergy and Infectious Diseases. https://www.niaid.nih.gov/diseases-conditions/treatment-living-food-allergy. Accessed February 2019.

20. Treating Allergic Reactions to Food. FARE. https://www.foodallergy.org/life-with-food-allergies/newly-diagnosed/treating-allergic-reactions-to-food. Accessed February 2019.

21. Treating Severe Allergic Reactions. FARE. https://www.foodallergy.org/life-with-food-allergies/epinephrine/treating-severe-allergic-reactions. Accessed February 2019.

22. Oral Immunotherapy. Anaphylaxis Campaign. https://www.anaphylaxis.org.uk/knowledgebase/oral-immunotherapy-2/. Accessed February 2019.

23. Treatment for Living With Food Allergy. National Institute of Allergy and Infectious Diseases. https://www.niaid.nih.gov/diseases-conditions/treatment-living-food-allergy. Accessed February 2019.

Kelly leads the creation of content that educates and empowers people with chronic illnesses. Learn more about her here.

A MyFoodAllergyTeam Member said:

Hey Miriam ...so sori to hear this...I'm having good days now ...just use the cream and bathcream morning and evening and I dnt even take allergy pills… read more

posted 3 days ago

hug

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