When food allergies are involved, navigating meals at home, school, work, and restaurants suddenly becomes much more challenging than simply deciding what you want to eat. People with mild food allergies may not have to be as careful, but those with severe allergic reactions causing anaphylaxis must pay close attention to where their food comes from and how it is prepared in order to avoid a life-threatening situation. 

Let’s take a closer look at food allergies, what they are, who has them, how to choose allergen-safe foods and snacks, and more. 

What are food allergies?

A food allergy occurs when someone has an immune-based reaction to ingesting, or sometimes even simply tasting or smelling, a specific food. This reaction repeats each time the person comes into contact with that food.

A food allergen is the specific component of the food—usually a protein but possibly a chemical additive when talking about processed foods—that causes the immune reaction. Most food allergens will still cause reactions even after cooking or alteration in some way. However, sometimes food processing may remove the food protein causing the allergic response.

Cross-reactivity between allergens can also occur, causing a person to react to another allergen that is similar in structure to the initial allergen. Shellfish and certain tree nuts are a common example of this.¹

Common food allergy signs and symptoms 

The signs and symptoms of a food allergy reaction include:

• Anaphylaxis: This is the most severe and dangerous symptom of a food allergy reaction, resulting in airway restriction within minutes of ingestion. This symptom mandates an immediate trip to the emergency room or use of an Epipen. 
• Vomiting
• Acid reflux
• Abdominal pain
• Diarrhea
• Itching in the mouth, tongue or throat
• Swelling of the lips or other tissues
• Skin rash 

Besides anaphylaxis, most of these symptoms are not life-threatening. But repeated reactions may cause more severe consequences over time.¹

Food allergy vs. intolerance

The basic difference between a food allergy and a food intolerance is that a food allergy involves an immediate or near-immediate immune response, like anaphylaxis or hives. A food intolerance, on the other hand, does not involve an immune-mediated response. For example:

• A cow’s milk allergy is caused by an immunologic reaction to milk protein.
• Lactose intolerance is caused by a person’s inability to digest lactose, the sugar found in milk. This is a digestive response rather than an immune response, though it may produce similar symptoms. 

In general, food allergies are considered to be a more serious health issue than food intolerances, though their symptoms may overlap. Often food intolerances are mistaken for food allergies, but food allergies are more rare, affecting about 5% of children under 5 years old and 4% of teens and adults. 

The growing impact of food allergies

Current scientific research indicates that food allergy prevalence seems to be on the rise.¹ However, it may affect children and adults a little differently. 

Food allergies in children

One in thirteen children in the United States has food allergies, classifying it as a major public health concern. The most prevalent allergens include peanuts, milk, shellfish, and tree nuts.² It is possible for a child to outgrow a food allergy, and new research has shown that introducing peanuts and peanut products at an early age can prevent allergies from developing in the first place.³ 

It is estimated that about 80% of young children with egg and milk allergies will outgrow them by age 16. However, allergies to fish, shellfish, and tree nuts are less likely to go away and may be lifelong.⁴

There is also now a peanut oral immunotherapy treatment that was approved by the FDA in 2020; however, the treatment presents risks of side effects, including allergic reaction.⁵ 

Food allergies in adults

Shellfish is the most common food allergy in adults, but the other common allergens are also prevalent, such as peanuts, food additives, spices, and tree nuts. Unlike children, adults are unlikely to desensitize to an allergen once they have become sensitive to it.¹

Public health impact of food allergies

Overall, the growing prevalence of food allergies is a burden on the healthcare system, especially for hospital emergency departments that see cases of life-threatening anaphylaxis.  Plus, food allergies can be very stressful for families and individuals, trying to ensure zero cross-contamination when eating out or simply preparing everyday allergen-safe meals.²

Allergen labeling, the FDA, and the 8 major allergens

In 2004, the Food Allergen Labeling and Consumer Protection Act identified eight major allergens: 

• Milk
• Eggs
• Fish 
• Shellfish
• Tree nuts
• Peanuts 
• Wheat
• Soybeans

These eight major allergens account for 90% of all food allergies. These allergens must be identified on food labels as well as the food source from which it derives. Unless the allergen is included in the regular name of the food (like buttermilk, for example), it must be identified either in parentheses immediately after the ingredient, for example: lecithin (soy), or in a list using the word “contains” following the full list of ingredients, for example: Contains egg and wheat.

To address potential cross-contamination during manufacturing or packaging processes, consumers may also see “advisory” statements, like “may contain [allergen] or “produced in a facility that also uses [allergen].” However, these statements do not absolve a manufacturer from adhering to good food safety and cleanliness practices. 

Ninth major allergen added: sesame

Earlier this year, President Biden signed legislation to make sesame the ninth major food allergen. This law states that all products containing sesame will have to be explicitly labelled in the same manner as the other top eight allergens. Previously, manufacturers were asked to voluntarily label a product when sesame was included as an ingredient.⁶ 

Peanut allergy: avoidance or early introduction?  

One of the top allergens affecting children and adults is peanut allergy, with its prevalence rapidly increasing over the past decade. 

For those affected by this allergy, it seemed that avoidance was the only option available, but then that assumption was flipped on its head. A landmark study in 2015 called Learning Early About Peanut Allergy (LEAP) showed that early introduction of peanuts to infants led to an 81% reduction of developing a peanut allergy, actually modulating the immune response in the early stages of the child’s development.^{3, 7} The findings of the study were subsequently endorsed by the American Academy of Pediatrics (AAP), recommending that children with high risk of peanut allergy be introduced to it in a safe way between 4-6 months of age.⁸

There is also now a peanut allergy drug called Palforzia that can be used with children ages 4 to 17 to reduce severity or ideally eliminate a peanut allergy.⁹ 

Practical tips for handling food allergies

Food allergies can be anything from a mild annoyance to life threatening, so it’s important to be vigilant when handling food for someone with food allergies. Here are some tips. 

Practice food safety when preparing meals and snacks. Wash all cooking tools with hot, soapy water to thoroughly clean them and consider having separate tools for preparing allergen-friendly foods. Always wash your hands before preparing food. Don’t use shared equipment such as grills or griddles to cook allergen-free food. Use separate utensils to serve separate foods and take care not to mix them while serving. Use special plates with either a different shape or color to designate allergen-free foods.¹⁰

Check all food labels. Some prepackaged foods have major allergens you wouldn’t expect. Always read the labels of any packaged foods you purchase. For example, soy sauce contains wheat, Worcestershire sauce contains fish, and chocolate chips often contain milk.

Introduce allergenic foods at a young age. Early introduction to peanuts, between 4-6 months of age can help children’s immune systems desensitize and accept the potential allergen. There is less evidence available for other top allergens such as eggs, but early introduction is still advisable. Only introduce one food at a time in an age appropriate form: scrambled eggs, milk, and smooth peanut butter are examples. Unless baby has a reaction to an allergenic food, continue to feed them small amounts of the food on a regular basis as part of a healthy diet.^{7, 8} 

Look out for innovative allergen-free food products on the rise. As allergies have become more prevalent, allergen-free food products are becoming more and more available too. Gluten-free, soy-free, dairy-free and other “free” products have been developed so that those with allergies can enjoy the same meals as the rest of the family, enjoy certain foods on special occasions, or simply have the reassurance that their food is safe. These foods can also help put parents’ minds at ease that they can send their child to school with an easy and safe snack, whether that child has allergies or not. 

Work with a dietitian to manage food allergies safely

Food allergies can be a serious health condition and difficult to navigate. Working with a dietitian and/or qualified nutritionist can help both diagnose and manage food allergies safely. A dietitian can also help pregnant women prevent and manage food allergies in babies through her nutrition during pregnancy, lactation, and baby’s diet from 1-3 years old. With children and adults, a dietitian can help individuals and families navigate meal prep, eating out, eating at school, nutrition education, and medical nutrition therapy when needed.¹¹