When you google “corn allergy”, the top links you get back seem to convey a picture of corn avoidance that is far less complicated than what I experience, and what the folks in my support groups and who contact me directly through my blog experience. Now, I’m not trying to bum anybody out here, but I am trying to keep everybody safe. Which does seem to bum people out a lot. But hey, I like being alive so I’m not bummed at all to know things that keep me that way.
Here are some of the things I see a lot of the most popular google hits on corn allergy get wrong. I’ve included references where I can, but in a lot of cases research on these kinds of things just haven’t been funded. So for some items all I really have is my own experiences, my own critical thinking, and reports from the patient community to go on. I would much prefer solid statistics and rigorous studies. If you would like to explore some of these topics in that manner, let me know and I will help you find volunteers to participate.
In the meantime, this is what I know, based on as much peer-reviewed research as I can find, the reports of 8,000 members in a support group, and many dozens of direct messages between myself and members of the corn allergy community:
Misconceptions about Corn Allergies
- Corn allergy reactions are only to the protein.
- If you have to avoid derivatives and traces of corn, you can do so by reading labels.
- If you have to avoid derivatives and traces of corn, you can do so by calling or emailing manufacturers and asking them if their product “contains corn”.
- Airborne reactivity to corn is impossible or at least incredibly rare.
- Coping with a corn allergy only involves avoiding foods that contain corn.
- The symptoms of a food allergy are limited to hives, hay-fever type symptoms, severe facial swelling, or throat closing.
- Food intolerances cannot cause serious reactions.
Incorrect: Corn allergy reactions are only to the protein. Starches, sugars, alcohols or other items synthesized using corn products as a starting material cannot cause an allergic reaction.
Allergens can be more than just proteins.
- Structural biology of allergens
Aalberse, Rob C., Journal of Allergy and Clinical Immunology , Volume 106 , Issue 2 , 228 – 238
Summary: IgE antibodies can bind to non-peptidic (non-protein) allergens.
- IgE-binding epitopes: a reappraisal.
Aalberse, R. C. and Crameri, R. (2011),
Allergy, 66: 1261–1274. doi:10.1111/j.1398-9995.2011.02656.x
Summary: General discussion on IgE binding.
- Strategies to Query and Display Allergy-Derived Epitope Data from the Immune Epitope Database.
Vaughan K, Peters B, Larche M, Pomes A, Broide D, Sette A.
International archives of allergy and immunology. 2013;160(4):334-345. doi:10.1159/000343880.
Describes methods for searching non-peptidic (non-protein) epitopes in a database.
- Galactose-α-1,3-Galactose: Atypical Food Allergen or Model IgE Hypersensitivity?.
Wilson, J. M., Schuyler, A. J., Schroeder, N., & Platts-Mills, T. A. (2017).
Current allergy and asthma reports, 17(1), 8.
Summary: Discussion of an IgE mediated allergy to the carbohydrate (sugar) found in mammalian meat.
Those articles are about allergens other than corn, but it’s intuitively obvious that if we barely have scratched the surface of identifying possible epitopes, we definitely don’t know ALL of the constituents of corn, peanuts, or other foods, that can cause an allergic reaction.
Protein-free in theory is not protein-free in practice.
Even if a person only reacts to the protein, if you look at the patents for many of the processes by which corn derivatives are made, especially for food-grade use which is less strictly regulated than lab use, it becomes clear that not a lot is done to purify the final product from its starting materials of corn.
Here’s a youtube review of citric acid production on aspergillus niger that discusses how it’s strained from the growth medium:
And here’s a patent that discusses simply centrifuging the mycelial growth out, which does nothing to remove any corn steep liquor that may not have been fully metabolized.
Whatever the reason, the patient experience is that we react to derivatives that “should” not contain protein.
I have a few research links to provide about this, but most of it you’ll have to just take my word as a patient, and as someone who’s in contact with a ton of patients. Again, if you’re someone that wants to conduct a rigorous study, please let me help you find some participants.
Almost everyone I’ve personally encountered with a corn allergy has to avoid sugar, starch, and food-grade alcohols derived from corn. Even the people who aren’t sensitive enough to need support groups or contact me for help.
Among the people that are sensitive enough to need a support group and/or reach out to me for help, most of us have to avoid more processed derivatives such as citric acid, lactic acid, ascorbic acid, and all of the other items found on the corn derivative list.
I have references on my “hidden corn” post showing *how* these items are from corn, but there isn’t a lot of research funded on proving that people have corn allergy reactions to them. We, as patients, just know that we do react to these things when they are derived from corn, and that we don’t when they aren’t, and we frequently have the reaction before we are aware of the corn-derived ingredients.
Here’s what I have for resources showing the possibility to reacting to corn based sugars, and starches. Unfortunately all I have is patient experience regarding ethanol or other derivatives. But it’s seriously a *lot* of patient experience.
- Probable anaphylactic reaction to corn-derived dextrose solution.
“…clinicians should be aware of the possibility of corn allergy due to the administration of i.v. fluids containing corn-derived dextrose.”
Vet Hum Toxicol. 1991 Dec;33(6):609-10.
- Annals of Allergy: “Anaphylaxis due to cornstarch surgical glove powder.”
- Package inserts stating to avoid corn dextrose in corn allergic patients: Insert 1 and Insert 2.
As I detail in my hidden corn post (linked above), there are all kinds of ways that cross contamination can occur and not have to be listed on an ingredient.
Just a few examples off the top of my head:
- Dusting the an oven tray or stone for loaves of bread or pizza with corn meal to keep them from sticking. Many places do list this if they do it, but many more do not and are not legally required to.
- Corn-derived citric acid added to wash water for produce items such as pre-cut (baby) carrots to prevent browning. (This is how dry iceberg salad sent me to the ER once with a swollen tongue and closing throat.)
- Shared equipment for mills, threshing, and shelling equipment used to process grains and beans.
- “Ingredients of ingredients” such as corn oil used as a carrier for the Vitamin D added to milk.
More info in my hidden corn post.
Incorrect: If you have to avoid derivatives and traces of corn, you can do so by calling or emailing manufacturers and asking them if their product “contains corn”.
Man, I wish this were true. I can’t tell you how many times I have people say, either directly to me or via the support groups, “Good news! I’ve contacted the company and they have verified that this product is corn free!”
Funny story, there doesn’t seem to be any reliable correlation between companies reporting this and people with corn allergy actually tolerating the item. In fact if there is one, it’s a negative correlation: Often when companies are confident that there is no corn in their product, they fail to answer questions accurately that would reveal where the hidden corn is.
I have a post discussing my experiences with calling companies about their products and giving some advice on getting a more accurate answer, and Von over at Avoiding Corn has some further explanation of why it’s so hard to get an accurate answer. That’s why we have the support groups- to trade stories of what we react to and tolerate and give ourselves slightly better than a random chance that we’ll tolerate the things we try.
I know from personal experience that it’s possible, and if I thought I wouldn’t literally die, I would prove it in a double-blind study.
As it is, most of my airborne reactions have happened when I had no idea there was a contaminant around, and I only found out after I had a severe reaction that there was corn near me.
And I’m not actually unusual. I see a *lot* of people that I don’t consider to be super sensitive to traces and cross contamination with corn who still react airborne to popcorn, cooked corn, and corn chips. Sorry, no statistics here- that would require resources I don’t have and no one has funded a study that I’m aware of. I just observe that I don’t see too many people in the support groups who avoid eating corn but can be around corn.
Having an adverse reaction to corn affects the medications you take, body products you use, and whether you can tolerate the air in many public places, including roads and highways.
Additionally many of the ingredients on the derivative list above are also found in bath and body products including soap and shampoo. Cross reference this list with the ingredients list of literally any soap, lotion, or cosmetic you pick up.
Additionally a number of airborne contaminants that are sometimes annoying to people but not usually considered dangerous for allergies are a big problem for corn allergy: stage fog effects (corn glycerin), vape fumes (also corn glycerin), the ethanol in gas fumes, corn starch in fire works. Most corn allergy suffers report issues with artificial scents and fabric softeners.
Incorrect: The symptoms of a food allergy are limited to hives, hay-fever type symptoms, severe facial swelling, or throat closing. Anything else is an “intolerance.”
Allergic reactions can cause a range of symptoms throughout the body.
Non-allergic food reactions can be serious or even deadly.
- Most food intolerances are though to be due to Immunoglobulin-G (IgG), while Immunoglobulin-E (IgE) mediates “true allergy” reactions. There is evidence that IgG reactions can cause anaphylaxis.
- The long-term effects of inflammation from consuming foods you are intolerant to can be serious.
- FPIES, or Food Protein-Induced Enterocolitis Syndrome, is a non-IgE food sensitivity that can be life threatening in the short term, and has a number of negative developmental implications for a child in the long term.
- Eosinophilic Esophagitis is another non-IgE-mediated food sensitivity that is very painful and can lead to permanent damage to the esophagus, causing the inability to swallow solid food.
- Mast Cell Activation Syndrome is a non-IgE-mediated food reaction that literally causes the exact same reaction as an allergic reaction- the degranulation of mast cells. It can therefore cause anaphylaxis and subsequently death.
In conclusion, any food you have an adverse reaction to is a food you should avoid, regardless of whether you have a “true allergy” or not.