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Food Allergies

Definition

Food allergies are the body’s response to proteins found in food. For more than 12 million Americans alone, food allergy is a significant medical condition. All food contains proteins that enter the body when the food is eaten, or in some cases if it is touched. Allergic reaction occurs when the body reacts to these proteins as if they were harmful, and for individuals with food allergy, the offending food is harmful.

Symptoms of food allergy vary and can range from mildly annoying to dangerous and life threatening. Symptoms of food allergy include:

  • tingling of the mouth
  • tingling or numbness in arms or legs
  • rash or hives
  • itching
  • abdominal cramps
  • vomiting
  • diarrhea
  • breathing difficulties
  • sudden drop in blood pressure (hypotension)
  • swelling of the tongue
  • swelling of the throat
  • loss of consciousness
  • death

The most serious symptom of food allergy is anaphylaxis. Anaphylaxis, also called anaphylactic shock, is a sudden and potentially life threatening allergic reaction in which the whole body reacts to an allergen. During anaphylaxis the airway constricts making breathing difficult. Vomiting and diarrhea may also occur as the digestive tract constricts. The skin may swell and become itchy with rash or hives especially in the face. This swelling may block airways as well. The

heart may race and the heart beat may become irregular as blood vessels around the heart expand.

Anaphylaxis is caused when the body encounters a substance it believes is toxic. This substance is an allergen and is also called IgE. When this occurs, the body produces a substance called histamine. Histamine is a protein that the body releases in reaction to a substance in the blood that the body believes is toxic. Histamine causes blood vessels to dilate or become larger and this causes the symptoms of anaphylaxis. The treatment for anaphylaxis is medication called antihistamine. The most common antihistamine is diphenhydramine hydro-chloride which is found over–the–counter drugs such as Benadryl. If taken immediately, this antihistamine can stop anaphylaxis before it becomes too serious.

In cases of severe allergy, an injection of a strong antihistamine called epinephrine or adrenaline may be needed. If allergy is suspected or if an individual has had a previous allergic reaction, an injectable form of epinephrine may be prescribed. An auto–injectable form of epinephrine that looks similar to a large ball point pen is kept on hand at all times. If a severe.

KEY TERMS

Adrenaline—(also called epinephrine) A hormone released by the body during times of stress, it increase heart rate and blood pressure. As a medication, it may be used to constrict blood vessels, relax breathing tubes, and as a treatment for anaphylaxis.

Allergen—Any substance that produces an allergic reaction.

Anaphylaxis (Anaphylactic shock)—A sudden, severe, and potentially fatal allergic reaction characterized by difficulty breathing, low blood pressure, hives, and swelling.

Antibody—Proteins in the blood that help defend the body against infection.

Antihistamine—Medication that stops the action of histamines.

Anti–inflammatory—Medication such as aspirin or Ibuprophen that reduces swelling.

Diphenhydramine hydrochloride (Benadryl)—An antihistamine that relieves allergy symptoms.

Epi-Pen—A the brand name of the auto–injectable form of epinephrine. Used to stop or prevent anaphylaxis after expose to an allergen.

Epinephrine—(also called adrenaline) A hormone released by the body during times of stress, it increase heart rate and blood pressure. As a medication, it may be used to constrict blood vessels, relax breathing tubes, and as a treatment for anaphylaxis.

Histamine—A substance that is released by the body in the presence of allergens. It stimulates dilation of blood vessels, constriction of breathing tubes, and decreased blood pressure.

IgE—A substance in the body that triggers the body to release histamine when an allergen enters the body. IgE is measured in allergy tests.

allergic reaction occurs,the auto–injector (brand named Epi-Pen) is held against the skin and the medication is administered with a shot. Epinephrine is a strong antihistamine that stops anaphylaxis very quickly.

There is no cure for food allergies; however, food allergies may be prevented. By avoiding foods that cause allergic reactions, an individual can prevent allergic reaction. Avoiding foods that cause allergic reactions is called an elimination diet.

Before food allergies can be avoided, the offending food must be identified. There are eight foods that cause 90% of all food allergies these foods include:.

  • milk
  • eggs
  • peanuts
  • tree nuts (walnuts, cashews, pecans, etc.)
  • fish
  • shellfish
  • soy
  • wheat

Origins

The fact that some foods cause physical illness has been recognized throughout history. It was the ancient Greek, Lucretius who first said, “One man’s food may be another man’s poison.” Throughout history, people have avoided foods that seemed to cause ill health. In the 1960s researchers began to document food allergies and to verify that avoiding these foods reduced or eliminated the allergy symptoms all together.

In the following 50 years, screening tests such as blood tests and skin tests were developed to assist in identifying food allergies. Treatment including antihistamines and anti-inflammatory medications have helped relieve symptoms, but an elimination diet remains the single most effective method to treat food allergies.

Description

Food allergies occur when the body has an abnormal reaction to a food eaten or touched. In some individuals, certain foods cause the body to produce histamine. This histamine travels throughout the body causing symptoms such as hives, swelling, wheezing, vomiting, or diarrhea. Once a food allergy has been identified, an elimination diet is the only effective treatment. By eliminating the food that causes the allergic reaction, allergic reaction to food may be prevented.

To identify food allergies, a doctor first records a detailed medical history. The patient will usually keep a food diary documenting exactly what is eaten and when. The patient will also record any physical symptoms and when they occur. In most cases, patterns of reaction to specific foods can be seen in the food diary. Other means of diagnosis food allergies includes.

  • Skin Tests—In a skin allergy test, a small amount of extract of a food that is suspected of causing an allergic reaction is placed on the skin, the skin is scratched in that area, and observed for reaction. If an allergy exists, a small bump (similar to a mosquito bite) will appear usually within 15 minutes. This is a rapid way to see if a food allergy exists
  • Food Challenge—This is a food test in which neither the testing doctor nor the patient knows what food is given. Opaque capsules are filled (by an assistant or another doctor) with foods that are suspected of causing allergies and foods that are not. The capsules prevent the patient from tasting or smelling the food. The patient swallows a capsule, and the doctor observes to see if a reaction occurs. This teat is not appropriate a person who has had a severe allergic reaction. It is time consuming and is usually performed when a doctor suspects the allergic reaction is not being caused by food. The test can rule out food as a cause for allergic reactions

After a food allergy is diagnosed, an elimination diet may be implemented. Avoiding foods that cause allergic reaction may sound simple, but it can be quite difficult. It is easy to avoid eating scrambled eggs or a handful of raw peanuts; however, many common food allergy foods are ingredients in many foods.

Reading Food Labels

It is essential that individuals with food allergies read the labels of every food they eat. Federal law called the Food Allergen Labeling and Consumer Protection Act (FALPCA) took effect January 1, 2006. This law mandates that all food containing milk, eggs, fish, crustacean shell fish, peanuts, tree nuts, wheat, or soy must note this on the label. To follow an elimination diet, it is essential to read these labels.

Ingredients that may cause allergies are listed on the label after the word “Contains”. If these ingredients have names which are not readily known as versions of foods that may cause allergic reactions, the manufacturer will list the allergen in parenthesis. For example, albumin (egg) or casein (milk) Foods that may be present as additives for coloring or texture must be listed as well. Manufacturer must also list the individual ingredient used and 160 foods that have been identified as causing food allergies must be listed.

According to the American Academy of Allergy, Asthma, and Immunology, many other foods and ingredients may contain parts of foods that cause allergies. These foods should be avoided when on an elimination diet.

Here is a list of other foods and ingredients that may contain foods which cause allergies:.

  • These may contain milk: Butter flavor, butter, butter fat, butter oil, buttermilk, casein, casemates, rennet casein, cheese, cream, half and half cottage cheese, custard, yogurt, pudding, ghee, all forms of milk from animals such as goats, sour cream, milk solids, lactalbumin, lactalbumin phosphate, lactoglobulin, and lactulose
  • These may contain eggs: eggnog, albumin or albumen, lysozyme, mayonnaise, meringue, surimi, lecithin, pasta, marzipan, marshmallows, and nougat
  • These may contain peanuts or ingredients that may affect people with peanut allergies: any nut or nut product, any nut butter, peanut oil, arachis oil, goobers, mandelonas, many candies and baked goods, nougat, sunflower seeds, and foods from ethnic restaurants such as—African, Chinese, Indonesian, Mexican, Thai, and Vietnamese

Be aware of the date of manufacturing of the foods in the pantry or on the store shelf. The new labeling requirements went into effect on January 1, 2006. Any food packaged prior to that date may not list all potentially allergy causing foods.

Function

The function of an elimination diet is to prevent potentially life threatening allergic reactions caused by food. Food allergies begin the second time an allergy-causing food is eaten or, in some cases, touched. The first time the food is consumed, the body reacts with an abnormal biological alarm. As the food is digested and broken down into proteins that enter the blood stream, protective cells called antibodies are formed. Normally, antibodies are used to attack germs such as bacteria or viruses that invade the body. In this case, antibodies protect from disease by destroying the germs. Antibodies prompt other reactions in the body such as fever to kill disease cells or dilating of blood cells so that blood can reach infected areas of the body more rapidly.

The second time the food is ingested, these antibodies alert the body that an invader is present, and the body mounts an attack. The body responds causing the symptoms of itching, rash, hives, breathing difficulties, swelling, or irregular heart beat. Doctors suspect that the reason some people become allergic to foods and other do not is genetic. Children of parents who have a significant allergic reaction to a food are more likely to have that food allergy as well.

Benefits

The benefits of following an elimination diet to prevent symptoms of food allergies include avoiding the discomfort of symptoms such as itching, stomach upset, and diarrhea. For individuals with severe food allergies, following an elimination diet may be lifesaving.

Precautions

If food allergy is suspected, it is best to consult a doctor. Removing foods from the diet can cause an unbalanced diet that may be deficient in necessary nutrients. Since some of the most common foods that cause allergies include milk, eggs, and wheat, significant sources of protein, calcium and fiber may be removed. With the assistance of healthcare professions, diets may be modified and healthy substitutions may be found.

Food allergy is becoming more common in children. Food allergies in children may be more severe. Anaphylaxis generally occurs suddenly. Symptoms of food may initially be more subtle in children. It is important to discuss any suspected food allergies with a doctor.

Most individuals with food allergy are allergic to only one food; however, peanut allergy may indicate reaction to tree nuts as well. Many manufacturers who process peanut products, process other nut products as well. Machines that handle and package these products may spread small pieces of peanut to other products. The FALPCA mandates that labels note this fact as well.

Risks

Risks of food allergy range from minor discomfort to death. Allergic reactions to food are serious and should be discussed with a doctor. Food allergy can come on suddenly. A food that did not previously cause a reaction may suddenly cause a severe reaction as the levels of antibodies in the body increase and allergy develops.

If food allergy is suspected, or if an allergic reaction has occurred, a doctor should be consulted. It may be necessary to keep an auto–injector of epi-nephrine on hand in case a sudden allergic reaction occurs again. These antihistamine injectors require a prescription and should only be used if a doctor has advised it.

There are few risks of following an elimination diet. However, a doctor should be consulted before eliminating foods rich in necessary nutrients such as milk, eggs, or bread. Suitable substitutions should be incorporated to insure that all necessary vitamins and minerals are maintained in the diet. Many children have food allergies. It is especially important to maintain a balanced diet in children during the important years of development.

Individuals following a special diet to treat other medical conditions should consult with a doctor before altering that diet. Eliminating foods from a previously prescribed diet may aggravate a medical condition and may be harmful.

General acceptance

The elimination diet is standard treatment for preventing allergic reactions to food once food allergy has been diagnosed. Virtually all doctors agree and there is much data to support the effectiveness of an elimination diet.

Some individuals report food sentivities. Food sensitivity is more subtle than food allergy and rarely causes anaphylaxis. Many people report being sensitive to a variety of foods and food additives. Food sensitivity is less well understood than food allergy. However, the numbers of individuals reporting food sensitivity is increasing, especially in the Western world. In response, there are more studies investigating food sensitivity.

Some doctors doubt the validity of claims of multiple food sensitivities. Food allergy has been well studied and well documented. Most individuals with a food allergy are allergic to only one food. Many people with food sensitivities report reactions to many foods. These reactions are sometimes vague but can be marked and significant. Reported symptoms of food sensitivity include:.

  • rash
  • itching
  • stomach upset
  • chronic diarrhea
  • insomnia
  • forgetfulness
  • asthma
  • inflammation of the joints
  • hyperactivity (especially in children)

Children may be affected by food sensitivity. Many parents report changes in behavior after a child has eaten a food for which they may be sentitive. Currently, researchers are investigating the role of diet, food allergy, and food sensitivity in children.

QUESTIONS TO ASK YOUR DOCTOR

  • Could I have more than one food allergy?
  • Is an elimination diet safe for me?
  • Are there any special precautions I should follow?
  • Are there any drug precautions I should be aware of while following this diet?
  • Do I need an Epi-Pen?

who have been diagnosed with attention deficit disorder and autism. Both conditions are affecting more children each year.

Doctors disagree about the impact of food on children with these conditions. However, many parents report successfully improving symptoms such as inability to concentrate, hyperactivity, and sleep disturbances by eliminating foods such as wheat from the diets of their children.

Research

In the early 20th century, pediatricians, Clements von Pirquet and Bela Schick coined the term allergy from the Greek words allos, meaning changed or altered, and ergon, meaning reaction. Dr. von Clements was one of the first doctors to study reactions to what would later be called allergens.

In 1943 the American Academy of Allergy, Asthma, and Immunology was formed. This and other organizations of physicians help coordinate and implement many of the research finding of the many studies conducted on allergies each year.

Allergy reportedly affects 38% of all Americans. The Royal College of Physicians reports that one in three adults have an allergy. In a survey of over 3000 adults, 43% reported food allergies.

Multiple studies report a decrease of symptoms when foods that cause allergic reactions are eliminated from the diet.

BOOKS

Beirman, W., D. S. Pearlman, G. G. Shapiro, and W. W. Busse, eds. Allergy, Asthma, and Immunology from Infancy to Adulthood. Philadelphia: W. B. Saunders, 1996.

Braly, James, M. D. Hidden Food Allergies: The Essential Guide to Uncovering Hidden Food Allergies and Achieving Permanent Relief. Laguna Beach, CA: Basic Health Publications, 2006.

Brostoff, Jonathan and Linda Gamlin. Food Allergies and Food Intolerance: The Complete Guide to Their Identification and Treatment Rochester, VT: Healing Arts Press, 2000.

Carter, Jill and Alison Edwards. The Allergy Exclusion Diet: The 28–Day Plan to Solve Your Food Intolerances. Carlsbad, CA: Hay House, 2003.

Cutler, Ellen, MD. The Food Allergy Cure: A New Solution to Food Cravings, Depression, Obesity, Headaches, Arthritis, and Fatigue. New York, NY: Three Rivers Press, 2003.

Speer, F., ed. Allergy of the Nervous System. New York, NY: Thomas, 1970.

Walsh, William E. MD. The Complete Guide to Understanding and Relieving Your Food Allergies. New York, NY: John Wiley and Sons, 2000.

PERIODICALS

Crowe, S. E. and M. H. Perdue. “Gastrointestinal Food Hypersensitivity: Basic Mechanisms of Pathophysiol-ogy.” Gasteroenterology 103, no. 3 (1992): 1075–1095.

Dreskin. “Role of Genetics in Food Allergy.” Curr Allergy Asthma Rep 6 (2006): 58–64.

Finn, R. “Food Allergies–Fact or Fiction: A Review.” Journal of the Royal Society of Medicine 85, no. 9 (1992): 560–564.

Iikura, Y. et. al, “How to Prevent Allergic Disease I. Study of Specific IgE, IgG, and IgG4 Antibodies in Serum of Pregnant Mothers, Cord Blood, and Infants.” Int Arch Allergy Appl Immunol 88 (1989): 250–252.

Sampson, H. A., L. Medelson, and J. P. Rosen. “Fatal and Near–Fatal Anaphylactic Reactions to Foods in Children and Adolescents.” New England Journal of Medicine 327, no.6 (1992): 380–384.

Sicherer, S. H. and Leurg, D. Y. “Advances in Allergic Skin Disease, Anaphylaxis, and Hypersensitivity Reactions to Food, Drugs, and Insects.” J Allergy Clin Immunol 116 (2005): 153–163.

Steinman, H. A. “Rostrum: Hidden Allergens in Foods.” Journal of Allergy and Clinical Immunology 98, no. 2 (1998): 241–250.

Winbourn, M. “Food Allergy, the Hidden Culprit.” Journal of American Academy of Nurse Practitioners 6, no. 11 (1994):515–522.

OTHER

Food Allergy Fact Sheet, American Academy of Allergy, Asthma, and Immunology, (2007) Website: http://www.aaaai.org/patients/resources/fact_sheets/food_allergies.pdf.

ORGANIZATIONS

American Academy of Allergy, Asthma and Immunology. 611 East Wells Street, Milwaukee, WI 53202. Telephone: (800) 822-2762. Website: http://www.aaaai.org.

The Food Allergy and Anaphylaxis Network. 11781 Lee Jackson Hwy., Suite 160, Fairfax VA 22033. Telephone: (800) 929-4040. Website: http://www.foodallergy.org/.

The Food Allergy Initiative, 1414 Avenue of the Americas, Suite 184, New York, NY 10019, Telephone: (212) 207-1974. Website: http://www.foodallergyinitiative.org

Deborah L. Nurmi, MS.

Food combining see Hay diet.


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