What are Food Additives and Preservatives?
There are thousands of substances added to various foods for the purposes of coloring, flavoring and preserving. Additives are usually only a very small component of foods, but have been suspected of causing various reactions. Food additives include the following groups:
Food dyes and colorings (such as tartrazine, annatto and carmine)
Antioxidants (such as BHA and BHT)
Emulsifiers and stabilizers (such as gums and lecithin)
Flavorings and taste enhancers (such as MSG, spices and sweeteners)
Preservatives (such as benzoates, nitrates and sulfites)
The Food and Drug Administration (FDA) keeps a list of all of the food additives currently used in the United States.
How Common are Reactions to Food Additives and Preservatives?
Since it is probable that many reactions to food additives are not diagnosed, the exact rate of reactions is not known. However, various studies estimate that the rate is probably less than 1% of adults, and up to 2% of children.
What Reactions Occur as a Result of Food Additives?
There are many types of reactions that can occur as a result of food additives. Some of these reactions suggest an allergic cause, while many others do not appear to be allergic, but rather an intolerance. Reports of reactions to food additives have included the following:
behavior and mood changes
attention deficit and hyperactivity disorder
How is Allergy to Food Additives Diagnosed?
A diagnosis of allergy to food additives is suspected when a person experiences various reactions to prepared foods or when eating at restaurants, but not from foods prepared at home. Various seemingly unrelated foods might in fact have common ingredients, such as food colorings or preservatives.
Once a food or food additive is suspected, allergy testing (using skin testing or RAST) may be possible to certain natural substances such as annatto, carmine, and saffron. Testing for synthetic substances is not possible or reliable, and therefore a trial of a preservative-free diet may support a diagnosis of food additive reactions.
In many instances, the only way to truly diagnose an adverse reaction to food additives is for the person to undergo an oral challenge with the suspected additive under close supervision of an allergist.
Which Food Colorings Cause Reactions?
Tartrazine.Also known as FD&C Yellow #5, tartrazine has been suspected as the cause of many reactions, including urticaria (hives), asthma and other illness. Recent studies have disproven the thought that aspirin-allergic asthmatics were especially sensitive to tartrazine. Other studies suggest a role of tartrazine as worsening atopic dermatitis.
Find out how to follow a tartrazine-free diet.
Carmine.Carmine is a red food coloring made from a dried insect called Dactylopius coccus Costa, which can be found on prickly pear cactus plants. This coloring is also found in various cosmetics, drinks, red yogurt and popsicles. Reactions to carmine are probably due to allergic antibodies.
Annatto. Annatto is a yellow food coloring made from the seeds of a South American tree, Bixia orellana. This additive has been found to cause allergic reactions, including anaphylaxis and urticaria/angioedema.
Saffron.This yellow food coloring, obtained from the flower of the Crocus sativa plant, has been reported as a cause of anaphylaxis.
Many other food colorings are less common, but possible, causes of adverse reactions. These include sunset yellow (yellow #6), amaranth (red #2), erythrosine (red #3), and quinoline yellow, among others.
What about Antioxidants?
Antioxidants such as BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) are added to prevent the spoilage of fats and oils. Both BHA and BHT are suspected of causing urticaria and angioedema.
What about Emulsifiers and Stabilizers?
Lecithin. Lecithin in an emulsifier made from soybeans and eggs, and may contain soybean proteins. Reactions to soy lecithin are rare, even in soy-allergic people, since the level of this additive is usually very low in most foods.
Gums.Various gums are used as food additives and function as emulsifiers and stabilizers. Major gums include guar, tragacanth, xanthan, carageenan, acacia (Arabic) and locust bean. Many of these gums are known to worsen to worsen asthma, particularly in the occupational setting, when airborne. Others are known to cause allergic reactions when present in foods.
Monosodium Glutamate (MSG). MSG is a flavor enhancer added to various foods, and also occurs naturally. Reactions to MSG have been called the “Chinese Restaurant Syndrome,” and symptoms include numbness on the back of the neck, shoulders and arms, weakness and palpitations. Other symptoms include facial pressure/tightness, headaches, nausea, chest pain and drowsiness. MSG is also suspected of worsening asthma symptoms.
Spices. Spices are the aromatic part of various weeds, flowers, roots, barks and trees. Because they are derived from plants, spices have the ability to cause allergic reactions, just like pollens, fruits and vegetables. The most common spices used include chili peppers, celery, caraway, cinnamon, coriander, garlic, mace, onion, paprika, parsley and pepper.
Aspartame. Aspartame is a sweetener used in many sugar-free foods and drinks. This food additive has been suspected of causing such symptoms as headaches, seizures and urticaria.
What Preservatives Cause Reactions?
Sulfites.Sulfites are common preservatives used in various foods, and are well known to cause a variety of symptoms. Learn more about sulfite allergy.
Nitrates and Nitrites. These additives are used as curing agents in meat products. Few reports of reactions to nitrates and nitrites exist, and include urticaria, itching and anaphylaxis.
Benzoates. Benzoates are used in foods as antimicrobial preservatives, and have been responsible for worsening asthma, allergic rhinitis, chronic urticaria, and flushing in some people.
Sorbates/sorbic acid. Sorbates are added to foods as antimicrobial preservatives. Reactions to sorbates are rare, but have included reports of urticaria and contact dermatitis.
How are Reactions to Food Additives Treated?
Many of the reactions to food additives, such as with MSG, are mild and resolve without treatment. More severe reactions, including urticaria, angioedema, worsening asthma and anaphylaxis may require immediate medical attention. These reactions are treated much the same way as other food allergies. If reactions are severe, it may be necessary for a person to be prepared for a severe reaction (such as carrying injectable epinephrine and wearing a medical alert bracelet.
Otherwise the mainstay of therapy for people with adverse reactions to food additives is avoidance of the culprit food additive.
Wilson BG, Bahna SL. Adverse Reactions of Food Additives. Ann Allergy Asthma Immunol. 2005; 95:499-507.
Bush RK, Taylor SL, Hefle SL. Adverse Reactions to Food and Drug Additives. In: Adkinson NF, Yunginger JW, Busse WW, et al, eds. Middleton’s Allergy Principles and Practice. 6th edition. Philadelphia: Mosby Publishing; 2003:1645-1663.
DISCLAIMER: The information contained in this site is for educational purposes only, and should not be used as a substitute for personal care by a licensed physician. Please see your physician for diagnosis and treatment of any concerning symptoms or medical condition.