The corn free diet removes not only corn kernels from meals, but also corn derivatives from products such as medications, food additives, and household supplies, which contain or are derived from corn. Most individuals who consume a corn free diet do so because they are allergic to the proteins in corn.
Symptoms of corn allergy are similar to any food allergy. These symptoms include skin rashes, hives, gastrointestinal distress (upset stomach). In the most extreme cases, an allergic person who has just consumed corn may experience breathing difficulty and even anaphylaxis, a life threatening condition where the throat swells and breathing may not be possible after the consumption of corn.
Although corn allergies are less common than soy or peanut allergies, the medical community has gained increasing awareness of this issue in recent years.
Some patients adopt a corn free diet under the instruction of their doctor. Corn is sometimes eliminated from the diet to see if symptoms resolve. If a patient's condition improves while on a corn free diet, the consumption of this food is reduced or eliminated.
Corn and its derivatives are in a large number of processed foods. Any food containing corn syrup, including ketchup, candied fruits, caramel coloring, vanilla extract, and pre-sweetened cereals are avoided.
Individuals experiencing unexplained exhaustion or repeated rashes may suffer from a corn allergy. As the cost of allergen testing decreases, an increasing number of individuals, especially children, are being tested for corn allergies. Many pediatricians now test for a wide range of allergies before considering more rare, and more serious, medical conditions with the same symptoms. Most individuals with corn allergies are put onto a corn free diet in order to eliminate the irritant.
Food allergies involve the body's immune system. The offending substance is known as an allergen. Although recent investigation into corn allergies has shown that they create a complex cascade of events in the body, the basic process of a body's reaction to an allergen is the same as with other substances. When the allergen is ingested, the body's immune system reacts to what it perceives to be a foreign invader. The body releases an antibody known as immunoglobulin E (IgE), which interacts with the allergen. Specialized tissue and blood cells connected to the IgE antibody release a substance called histamine, which is responsible for the uncomfortable, and sometimes life threatening symptoms that occur when an allergen is ingested.
Reactions to allergens occur throughout the body as the immune system tries to contain and eliminate the foreign invader. The most common locations where the allergic reactions occur include the mouth, digestive tract, skin, and airways. The lips and mouth may swell. Stomach cramps, vomiting, and diarrhea may result. Hives, rashes, or eczema may appear on the skin. In severe cases, wheezing or breathing problems may develop.
Skin allergy testing (so called "scratch tests") are not always a reliable way to test for food allergies. Some individuals who are reactive to ingested food may not show a reaction on a scratch test. Scratch tests offer only a localized response to an allergen, whereas ingested food may have a more systemic effect. This is because the body changes food as it is digested. The body also is exposed to a significantly higher amount of the allergen during ingestion. The exclusion of corn products from the diet and lifestyle, therefore, offer a much more comprehensive data on possible allergy.
Currently there are no available high-quality trials evaluating the corn free diet.
Asensio T, Armentia A, Lombardero M, et al. Cereal-induced anaphylaxis in an adult after eating a baby cereal formula. Allergol Immunopathol (Madr). 2004 Sep-Oct;32(5):310-1.
American Academy of Allergy Asthma & Immunology.
Foodsafety.gov: Gateway to Government Food Safety Information. 19 June 2006.
National Food Service Management Institute. 19 June 2006.
International Food Information Council. 19 June 2006.
Spergel JM, Andrews T, Brown-Whitehorn TF, et al. Treatment of eosinophilic esophagitis with specific food elimination diet directed by a combination of skin prick and patch tests. Ann Allergy Asthma Immunol. 2005 Oct;95(4):336-43.
Weichel M, Vergoossen NJ, Bonomi S, et al. Screening the allergenic repertoires of wheat and maize with sera from double-blind, placebo-controlled food challenge positive patients. Allergy. 2006 Jan;61(1):128-35.
Individuals who adhere to a corn free diet must become adept at reading food labels. Almost all types of processed food products contain trace amounts of corn.
Followers of the corn free diet often have to cook for themselves. At restaurants, it is important to remember that each product in a recipe may include many sub-ingredients. Foods may be cooked in corn oil. At social gatherings, followers of this diet may ask to examine ingredient packages, or bring a food product that they know is corn free.
Individuals adhering to a corn free diet often shop at natural food stores to avoid products containing corn products, especially corn syrup.
Individuals following the corn free diet must become familiar with the many words for corn, such as dent corn, flint corn, flour corn, maize, pod corn, sweetcorn, waxy corn, zea, and Z. mays. Frequent substitutions for corn include barley, buckwheat, millet, oats, potatoes, rice, rye, spelt (a type of wheat), sweet potatoes, and wheat.
Baked goods to avoid: Commercial backed goods that contain corn syrup or HFCS (high fructose corn syrup), biscuits, Bisquick and pancake mixes that contain corn syrup, granola bars and cookies that contain corn syrup or HFCS, modified cornstarch, pie crusts and cake mixes that contain corn syrup or HFCS.
Baking ingredients to avoid: Baking powders, most (corn free baking powders are available that use arrowroot powder or potato starch instead of cornstarch), caramel coloring (may contain corn syrup), cornstarch, cornmeal, vanilla extract (many brands contain corn syrup; some brands do not), yeast (except Red Star dry yeast).
Beverages to avoid: Coffee, evaporated milk, frozen orange juice (except Minute Maid), gin, whiskey, and any alcoholic beverage or soft drink containing malt, malt syrup, or malt extract, Hawaiian punch, Hi-C, infant formulas (Enfamil, Modilac, and Similac), instant coffee, Mott's apple juice.
Cereals to avoid: Cereals listing corn, corn syrup, or HFCS on labels, corn flakes, grits, pre-sweetened cereals (most).
Dairy to avoid: Ice cream and sherbets that contain corn syrup or HFCS, flavored yogurts that contain corn syrup or HFCS.
Desserts to avoid: Candy, frostings, and carob desserts that contain corn syrup or HFCS, fritos, graham crackers, jellies, jams, and peanut butter that contain corn syrup or HFCS, Jello, marshmallows, popcorn, products containing xanthan gum, puddings that contain corn syrup or HFCS.
Fruits to avoid: Candied fruits, canned fruits, and dried fruits that contain corn syrup or HFCS, frozen and sweetened fruits that contain corn syrup or HFCS, fruit desserts that contain corn syrup or HFCS.
Meats to avoid: Bacon and cooked meats in gravies that contain corn syrup or HFCS, cured ham, sausages, and wieners that contain corn syrup, HFCS, or glucono-delta lactone (GDL), luncheon meats and sandwich spreads that contain corn syrup or HFCS.
Medicines to avoid: Dextrose is common in intravenous solutions, most solid or liquid medicines and dietary supplements contain cornstarch. Inquire to the manufacturer, because additional ingredients may not necessarily appear on the label.
Miscellaneous products to avoid: Bath or body powder (may contain corn starch), some emollient creams and toothpastes, as a texturizer and carrying agent in some cosmetics, envelopes, labels, stickers, stamps, tape, plastic wrap, paper cups, paper plates, some plastic food wrappers, sorbitol in oral hygiene products (mouthwash and toothpaste), and Zest soap.
Sweeteners to avoid: Confectioners sugar (many brands contain cornstarch; some do not), "corn sugar," corn syrup, dextrose (iodized table salt contains dextrose), "fruit sugar," glucose, golden syrup, high fructose corn syrup, "invert sugar," "invert syrup," malt, malt syrup, malt extract, sucrose labeled "from corn," and treacle.
Vegetables to avoid: Corn, hominy, ketchup that contains corn syrup or HFCS, succotash.
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.