Original photo by michellegibson/ iStock
Allergies are a pain — and can sometimes even be fatal. For those with food allergies, obsessive label-checking is a way of life, to seek out sneaky ingredients like soy or wheat. Some allergens have to be prominently displayed on packaging, but people with less common allergies have to be extra-careful.
Where do food allergies come from, and how do they work? How are they different from intolerances? Can seasonal allergies affect how we react to food? These nine fast facts about food allergies could help shed some light on something millions of people struggle with.
Nine Foods Cause the Most Food Allergy Reactions
Just about any food can cause an allergic reaction, but nine foods, known as the “big nine,” are responsible for around 90% of food allergies: milk, soy, eggs, wheat, peanuts, tree nuts, sesame, fish, and shellfish. For children, milk is the most common allergy; for adults, it’s shellfish.
Sesame Allergies Are on the Rise
Until very recently, the “big nine” was the “big eight” — sesame wasn’t included until a few years ago. Because sesame allergies affect around 1 million people, however, the United States declared sesame a major allergen in 2021. As of 2023, the Food and Drug Administration (FDA) requires clear labeling of all foods that contain sesame.
Food Intolerances Are Fundamentally Different From Food Allergies
Allergic reactions are caused by the immune system. The body identifies a food — say, shrimp — as an invader, even though it’s not actually harmful, and produces antibodies to defend against it. Those antibodies spread to other cells in the body, which release chemicals that cause an allergic reaction. A serious, sudden reaction is called anaphylaxis, and it can be life-threatening.
Intolerances are very real problems, but they work differently. When someone has an intolerance, they’re not able to properly digest certain foods, whether it’s because of a sensitivity, an enzyme deficiency, or a condition such as irritable bowel syndrome. This can cause gastrointestinal distress or other symptoms, although reactions are generally less severe than they are with allergies.
More Interesting Reads
Nonfood Items Can Trigger Food Allergies
Food allergies can apply to more than just food, and people with food allergies may have to avoid lotions, soaps, or even medication. Someone with an almond allergy may have a reaction to a lotion with almond oil in it, for example. Food additives show up in unexpected ways; milk or egg can show up in shampoo, and sesame oil is a common ingredient in lotions and soaps.
Food Can Trigger Pollen Allergies
Are you prone to hay fever? Some fruits and vegetables may trigger a mild reaction when you eat them — usually itching, tingling, or swelling of your lips, mouth, and throat. This is sometimes called pollen food allergy syndrome, and it’s not usually serious. Not everybody with seasonal allergies gets these reactions, but allergens tend to be associated with certain foods; if you have a grass allergy, for example, you’re more likely to react to celery, melons, oranges, peaches, or tomatoes.
33 Million People Have Food Allergies in the United States
There are around 333 million people in the United States, and around 33 million of them have some kind of food allergy, according to the advocacy group Food Allergy Research and Education (FARE). That’s about 1 in 10 adults and 1 in 13 children. Every year, around 200,000 people have medical emergencies related to food allergies.
People With Egg Allergies Don’t Have to Avoid Egg-Containing Vaccines
It’s a common misconception that people with egg allergies have to avoid certain vaccines — you’ve probably been asked if you have an egg allergy before getting one. This is because most flu vaccines have some egg protein in them. But according to recent research, it’s unlikely to trigger an allergic reaction, even among people with severe egg allergies. (Still, it’s always good to check with your doctor beforehand.)
Some Kids Outgrow Food Allergies
Childhood allergies aren’t necessarily forever, although the likelihood that a kid will outgrow them depends on what they’re allergic to and how severe the allergy is. About 60% to 80% of children with milk or egg allergies will outgrow them by age 16, especially if they’re able to eat these items in a baked good. Only 20% of kids with peanut allergies will outgrow them, though — and it’s even less likely to outgrow a tree nut or shellfish allergy.
Food Allergies Can Develop at Any Age
Allergies are often thought of as a childhood issue or something you’re born with — but the reality is that you can develop an allergy to anything at any point in your life, even foods that you’ve enjoyed for years. Fish and shellfish are the most common allergies to develop after childhood. In a 2019 survey, around half of adults with allergies reported developing them as adults.
Sarah Anne Lloyd is a freelance writer whose work covers a bit of everything, including politics, design, the environment, and yoga. Her work has appeared in Curbed, the Seattle Times, the Stranger, the Verge, and others.
