It’s easy to tell if some foods have corn in them, like cornstarch or popcorn. However, corn can also be hidden in many other foods and products.
Foods made in a certain way also tend to have corn in them, such as food that’s been changed to make it last longer or taste better (processed). About 75% of processed foods list corn as an ingredient.
It’s important to know if your symptoms are from an allergy. Once you know for sure, you can take steps to stay safe.
This article will explain the symptoms of a corn allergy, how it’s treated, and what you can do to prevent a reaction.
How Common Is a Corn Allergy?
We don’t know how many people have a corn allergy. There has not been a lot of research on it. Here are two studies that looked at how common corn allergies are:
A 2016 study in Pakistan used a food challenge test to see how many people had a corn allergy. In this test, a provider has a person eat a little bit of the food that might be causing allergy symptoms. Throughout the test, the person will eat more of the food and the provider watches to see if the person has an allergic reaction. The study in Pakistan that used this type of test found that about 1% of the population is allergic to corn. A study in Honduras tested 50 adults for a corn allergy. About 6% of them were found to be allergic to corn.
Having a corn allergy might not be common. It’s also possible that more people are allergic to corn and don’t know it. They may not realize that corn is causing their symptoms.
Signs and Symptoms
Food allergies can have a range of symptoms. You may have many of them or just a few. Corn allergy symptoms can include:
Hives Itching in/near the mouth (oral allergy syndrome) and other parts of the body Flushing or reddening of the skin Hay fever-like symptoms (sneezing, nasal congestion, and runny nose) Wheezing and asthma symptoms Headaches Abdominal pain Nausea and/or vomiting Diarrhea
Sometimes, an allergy can cause a serious reaction. A person who is very allergic to corn can have anaphylaxis. The signs and symptoms of an anaphylactic reaction include:
Swelling and/or tightness of the lips, tongue, throat, neck, or faceTrouble breathingHoarse voiceLightheadednessFast heart rateLethargy, confusion, or loss of consciousnessFeeling very uneasy (a sense of “impending doom”)
Causes
We know what causes some food allergies, like nuts, shellfish, and wheat. We’re not sure why people are allergic to corn. Genetics, environment, and the way that genetics and the environment interact (epigenetic factors) probably play a role in corn allergies.
A protein in corn called zein could be what causes an allergic reaction. When zein gets into the body, the immune system might see it as an invader that needs to be fought. The body releases antibodies called immunoglobulin E (IgE) as a defense.
IgE tells the cells in the immune system to put out substances called histamines. It’s the histamines that cause allergy symptoms.
Triggers: Foods and Products
Allergic reactions can happen from eating raw or cooked corn. It can also happen if you eat foods that were made using corn products.
Not all corn products contain zein, but it can be hard to know which ones do. Food labeling rules do not have “corn-free” as a designation.
Some items that are not food can also cause a reaction if you’re allergic to corn. For example, medical products like surgical gloves and intravenous (IV) fluids are often made with corn products.
Other Allergies
People with a corn allergy can also get symptoms from corn pollen, grass pollen, and cornstarch. These allergens can cause symptoms of hay fever (allergic rhinitis) and/or asthma.
If you have asthma, eczema, hives, hay fever, or other food allergies, you might be more likely to be allergic to corn. Having someone in your family with a corn allergy, especially a sibling, also makes you more likely to be allergic to it.
Diagnosis and Testing
If you have an allergy, your health and safety depend on you knowing how to avoid what you’re allergic to. However, diagnosing food allergies can be tricky.
Allergy testing with blood tests and skin tests does not always give results that are right. These tests often say that a person is allergic to something when they really aren’t. This is called a false-positive test result.
The first step in figuring out if you have a corn allergy is talking to your doctor about your symptoms. For example, you might notice that you always get the same symptoms after you eat corn or any food that has corn in it.
Food allergies can be hard to spot, but a corn allergy can be tricky because:
Corn is found in many foods and in varying amounts. The signs and symptoms of a corn allergy can also be caused by a lot of other allergies and health conditions. You might not even realize that your symptoms are related to corn. For example, you might just think you have a rash from a new body care product you’ve been using or that your stuffy nose is from a cold.
It can be helpful to keep a food diary. In it, you write all the foods that you eat, as well as when you ate them and whether you had any symptoms after.
Sometimes, cutting any foods that have corn in them from your diet can help you figure out if it was causing your symptoms. This is called an elimination diet. Once you stop eating foods with corn in them, you slowly start putting them back in. If you notice that you start having symptoms only after you start eating corn again, it can be a sign that you’re reacting to it.
You might need to do a food challenge test. Instead of avoiding corn, you will eat it on purpose. However, you’ll do this with a doctor present to make sure that if you have a reaction, someone is there to help you.
Treatment
If you only get mild allergy symptoms after eating corn, you may not need to do anything to treat it. You may find that taking an over-the-counter (OTC) medication to ease your symptoms is enough until the reaction passes.
Your doctor might ask you to keep a food diary or try an elimination diet. A food challenge test can also be used to find out if corn is causing your symptoms.
The main way to treat a corn allergy is to prevent a reaction in the first place. That means doing your best to avoid corn and corn products.
If you have a serious allergy, you will need to be prepared. Epinephrine (EpiPen) is the only way to treat an anaphylactic reaction. You will need to carry one with you and know how to use it.
Anaphylaxis is a medical emergency, so you’ll need to go to the emergency room or call 911 if it happens.
Prevention
The best way to prevent an allergic reaction is to avoid what you’re allergic to. However, that’s not always easy to do. There are many hidden sources of corn in foods and other products. These items also don’t have to be labeled to let you know that they have corn in them. That means it’s easy to be exposed to corn by accident.
If you have a severe allergy to corn, you might want to wear a medical alert bracelet. That way, emergency responders will know about your allergy even if you are unable to tell them.
Even if you know what to look for, you won’t always have the option. For example, you may not have an ingredients list to look at when you’re eating at someone else’s home or at a restaurant.
When you’re dining out, don’t be afraid to talk to the person preparing your meal. You can ask them about the ingredients and how they are making the food. For example, if a dish is made without corn but made with corn oil, it could still trigger a reaction.
Children who are allergic to corn may have a harder time avoiding it. If you’re a caregiver for a child with a corn allergy, you’ll need to make sure that the school knows and that they can take steps to keep your child safe. You’ll also need to talk to the caregivers of your child’s friends before birthday parties and playdates.
Following a Corn-free Diet and Lifestyle
If you have a corn allergy, there are foods and ingredients that you should not eat. There are also some corn-based ingredients that are OK for some people with a corn allergy. You will need to talk to your doctor about whether you can safely have them in your diet.
Foods That Always or Often Contain Corn
Corn syrup and high-fructose corn syrup (HFCS)Corn oil and vegetable oilCornmealCornstarchMaizePopcornGritsHominyCorn sugars (including dextrose, dextrin, maltodextrin, fructose, Dyno, Cerelose, Puretose, Sweetose, glucose, sorbitol, xylitol, inositol, sodium erythorbate)MargarineCorn chips and tortilla chipsCorn frittersSome breakfast cereal (such as corn flakes)Corn tortillas
Foods That May Contain Corn Products
Here are a few examples of foods that often have corn products like cornstarch, corn syrup, and corn/vegetable oils in them.
Vegetable commercial soups and chiliPeanut butterMeats including cold cuts like bologna, ham, hot dogs, sausages, and baconBreaded or fried foodsCheese and cheese spreadsChop suey and chow meinFish sticksFried potatoes or fried rice (if corn oil is used)Frozen mixed vegetablesCanned or creamed vegetablesSuccotashPork and beansBread dusted with cornmealGraham crackersBaking mixes, pancake mixes, and pancake syrupsEnglish muffinsTacos and tamalesPolentaGravies that have been thickened with cornstarchSalad dressings and saucesCanned or frozen fruits sweetened with corn syrupDates and other fruit confectionsIce creams and sherbetsChocolate milk, milkshakes, soy milk, eggnog, and yogurtAmerican wines, whiskey, gin, beer, and aleCarbonated beverages (including soda like Coca-Cola and 7-Up)Lemonade mixesInstant coffeesJams and jelliesCandies and chewing gumsMarshmallowsKetchup and mustard (prepared)White distilled vinegarMonosodium glutamateBaking powder, powdered sugar, cake yeast, and bleached flourGelatin capsulesVanilla extractMalt syrup, modified food starch, caramel, cellulose, and xantham gum
Non-Food Items That May Contain Corn
There are also many items that are made with or using corn. Even though you don’t eat these things, they might trigger a reaction if you’re around them.
Adhesives on envelopes, stickers, and stampsPaper containers like boxes, cups, plates, and milk cartonsFood wrappers with cornstarch coatingsStrawsToothpasteLaundry starchMedical products like surgical gloves coated with cornstarch and dextrose intravenous (IV) solutionPet FoodSome clothing and fabricsCrayonsDishwasher soapShampooPaint
Summary
A corn allergy is a type of food allergy. It’s not very common to be allergic to corn, but it can be serious. If you have symptoms after eating corn or using products made with corn, talk to your doctor.
Many products, even non-food items, have corn in them or are made using corn. If you have a corn allergy, it can be hard to avoid them. That said, your healthcare team can help you find ways to avoid corn and prevent an allergic reaction.
A Word From Verywell
Finding out you’re allergic to corn can be frustrating because so many foods and other products are made with it. Avoiding corn as much as you can is the best way to prevent allergy symptoms.
If you’re adjusting to a corn-free diet, start with foods like eggs, meat that is fresh and does not have chemical preservatives (unprocessed), oats, wheat, quinoa, beans, and rice. You might even be able to find corn-free versions of your favorite food and non-food products at health food stores.
Living with any allergy means having a lot to learn. Luckily, there are many resources to help. For example, the Food Allergy Research and Education organization offers tips for living with a food allergy. It also provides information on how to prepare for and manage severe reactions.
More common symptoms of a corn allergy include hives, itching, skin flushing, runny nose, sneezing, wheezing, headaches, abdominal pain, nausea, vomiting, and diarrhea.
