Imagine starting every meal, every snack and every little hunger-driven nibble wondering if one bite of the wrong food might hurt or kill you. That’s a daily reality for anyone living with food allergies.
Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Nine foods in particular account for more than 90% of serious allergic reactions like anaphylaxis. The list includes milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soybean and sesame.
In the United States, these allergens must be specifically declared on food ingredient labels. Let’s take a closer look at these common food allergens with allergist Jaclyn Bjelac, MD.
Identifying major food allergens
Food allergies saw a dramatic rise beginning in the early 1990s. The number of cases skyrocketed so much that researchers declared food allergies an epidemic. Managing allergies — and knowing how to avoid allergens — became a priority.
“The best defense against a food allergy is avoidance,” says Dr. Bjelac. “But to avoid a food, you have to know where it is.”
Lawmakers in the United States passed the Food Allergen Labeling and Consumer Protection Act of 2004. It identified eight foods as major allergens and set labeling and manufacturing requirements to better help people avoid those allergens.
Legislation in 2021 added a ninth food to the major allergens club. Labeling laws regarding sesame took effect on January 1, 2023.
Here’s why each allergen earned a spot on the list.
Got milk? The answer is a definite NO for an estimated 6.1 million Americans with a milk allergy.
An allergy to cow’s milk protein is the most common food allergy in infants and young children. Between 2% and 6% of children may be allergic to cow’s milk, according to some research estimates.
A milk allergy makes all dairy products off-limits, too. That means no butter, cheese, ice cream, yogurt … well, you get the picture.
“It can be extremely limiting and also very isolating,” notes Dr. Bjelac. “Imagine being a kid and not being able to have cake or ice cream at a birthday party. It can make for some challenging experiences.”
The good news? Most kids outgrow a milk allergy, often within a few years.
Milk allergy vs. lactose intolerance
It should be noted that having a milk allergy is different from being lactose intolerant — and potentially far more dangerous.
A food allergy triggers an overreaction from your immune system, explains Dr. Bjelac. If you have a milk allergy and consume milk, symptoms can range from mild (rashes and hives) to deadly (swelling that closes your airway).
But if you’re lactose intolerant, you’re dealing with a digestive issue. Basically, your body is missing an enzyme that allows it to digest lactose, or the sugar in milk and dairy. That can lead to nausea, gas and diarrhea if you consume milk, but it isn’t life-threatening.
Learn more about the differences between a food allergy and food intolerance from a registered dietitian.
Avoiding eggs if you have an egg allergy can be difficult. Sure, it’s easy to stay away from an actual egg. (They’re pretty easy to spot, after all.) The issue is when eggs go into making certain foods.
Eggs can sometimes be found in bread, waffles, pasta, pretzels, marshmallows … even specialty drinks. “Egg tends to hide in food,” says Dr. Bjelac. “Sometimes, you just can’t tell that it’s there — which adds a definite degree of difficulty when you’re trying to stay safe.”
But sometimes, people with an egg allergy can tolerate eggs if they’re baked into food. (Cake, as an example.) It’s best to consult with your allergist on this.
Like milk allergies, egg allergies are more common in children and are typically outgrown. Learn more about how to detect food allergies in children.
Peanut allergies grab a lot of attention. It’s easy to understand why.
Violent reactions to peanuts lead to more emergency room visits for food-induced anaphylaxis than any other food, research shows. It’s the third-most common food allergy along children and adults.
About 1 in 5 children with peanut allergies currently outgrow the condition. There’s hope that new treatment approaches may improve those numbers, says Dr. Bjelac.
So, why does this list include peanuts and tree nuts? Because they’re completely different despite sharing the nutty name.
Peanuts are actually a legume grown underground, making them a cousin of beans or peas. Tree nuts, on the other hand, are exactly what you would think given the name: They’re nuts that grow on trees.
Common examples of tree nuts include walnuts, almonds, hazelnuts, pecans, cashews and pistachios, explains Dr. Bjelac. U.S. food labeling laws name 18 tree nuts that must be identified on products.
It’s a good thing, too, because tree nuts can pop up in some pretty unusual places. (BBQ sauce, as an example.)
Reactions to tree nuts are the second-most common reason for an ER trip related to a food allergy. Allergies to tree nuts tend to be lifelong, though a small percentage of children outgrow the allergy.
The most common food allergen comes from the seafood section.
Shellfish allergies are the top food allergy for adults and the overall population. People can be allergic to crustaceans (such as shrimp, crab and lobster) or mollusks (like clams, oysters, scallops, snails and octopus).
Many people learn they’re allergic to shellfish as an adult when diets become a bit more adventurous. (“I don’t know how many 2-year-olds are going for the shrimp tray at parties,” notes Dr. Bjelac.)
Allergies to shellfish tend to be lifelong.
If you’re allergic to fish, odds are you’re allergic to all fish. “Most finfish have very similar allergenic proteins, so if you’re allergic to one, it’s very likely that you would be allergic to others,” clarifies Dr. Bjelac.
So, while tuna, salmon, cod and catfish most commonly set off allergic reactions, just about any of the 20,000 species of fish swimming around on Earth can probably do the same.
Like shellfish, most learn that they’re allergic to fish as adults.
But while fish and shellfish both fall in the seafood category of the menu, they’re extremely different biologically. So, you can be allergic to fish but not shellfish, and vice versa, adds Dr. Bjelac.
A wheat allergy is another example of a food allergy that’s more common among younger children before disappearing with age.
But while it’s present, it can complicate life. Wheat is pretty popular, after all. The world’s farmers grow almost 800 million metric tons of the grain every year. It’s safe to say it ends up in a lot of different foods.
A wheat allergy is different from celiac disease and gluten intolerance, also known as non-celiac gluten sensitivity (NCGS). (Learn more as a gastroenterologist breaks down both of the conditions.)
“As with other food allergens, treatment for wheat allergy is strictly avoiding it,” states Dr. Bjelac.
The good news? With the growth in wheat-related health issues, there has been an influx in wheat alternatives that weren’t widely available a decade ago. Lean on other grains such as amaranth, corn, oats, quinoa or rye.
Soybean allergies are more typical during childhood and often go hand-in-hand with other food allergies, particularly peanuts. One study found that 88% of children with a soy allergy also had a peanut allergy. (Both are legumes.)
Avoidance of soybeans can be difficult given how often they end up in processed foods. But many people with a soy allergy can tolerate products containing soy lecithin, says Dr. Bjelac.
Talk with your allergist to determine what, if any, soy products might be OK to eat.
“An allergist can work with you to safely determine what should or should not be restricted when it comes to soy,” she says. “Being able to add in certain elements can be really empowering to patients and their families.”
Sesame has grown into a leading cause of food-induced anaphylaxis around the world, a fact that earned it a designation as a major allergen.
It’s not just a matter of avoiding easy-to-spot sesame seed buns, either. Sesame is a common ingredient in many prepared foods. (Hummus, for instance.) It can be used in many forms, too, including flour, oil, paste and salt.
U.S. laws requiring sesame to be clearly noted on food labels began in 2023. Be aware that packaged foods manufactured in 2022 or earlier may contain unidentified sesame. “That’s something people managing a sesame allergy will have to navigate for a while,” Dr. Bjelac notes.
Final thoughts on food allergens
While the nine foods listed above are the most common causes of allergic reactions, they are far from the only foods that can start trouble. In fact, more than 170 foods have been identified as allergens.
“It’s unfortunate we’re seeing food allergy prevalence increasing,” says Dr. Bjelac. “But thankfully, that has brought an increased awareness and understanding about what it means to have a food allergy. That’s a big step toward helping people manage it.”
If you have a food allergy, Dr. Bjelac advises you to read every label, every time, to ensure food is safe. Always carry your prescribed epinephrine auto-injector to administer medicine in case of an allergic reaction, too.