True food allergy (also known as food hypersensitivity) affects fewer than two out of every 100 people. Children are 2 to 3 times more likely that adults to be allergic to food, but many childhood allergies seem to disappear as the children grow older.
So, you may ask, why do I need to learn about food allergies? Good question. Here's the answer: Food allergies that do not disappear can trigger reactions ranging from trivial (a stuffy nose the next day) to the truly dangerous (respiratory failure). So it pays to know which foods do what.
What is a Food Allergy?
Your immune system is designed to protect your body from harmful invaders, such as bacteria. Sometimes, however, your immune system responds to substances that are normally harmless. A food allergy is just such a response - your body fighting back against specific proteins in foods.
Symptoms of an Allergic Reaction To Food
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Reactions:
Hives
Itching
Swelling of the face, tongue, lips, eyelids, hands, and feet
Rashes
Headache, migraine
Nausea and/or vomiting
Diarrhea, sometimes bloody
Sneezing, coughing
Asthma
Breathing difficulties caused by tightening (swelling) of tissues in the throat
Loss of consciousness (anaphylactic shock)
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Two kinds of allergic reactions
Your body may respond to an allergen immediately or later on.
Immediate reactions are more dangerous than delayed reactions because they involve a fast swelling of tissues. Immediate reactions may occur within seconds after eating, touching, or - in some cases- even smelling the offending food.
Delayed reactions may occur as long as 24 to 48 hours after you've been exposed to the offending food, and the reaction is likely to be much more mild, perhaps a slight nasal congestion caused by swollen tissues.
How an allergic reaction occurs
When you eat a food containing a protein to which you are allergic, (the allergen), your immune system releases antibodies that recognize just that specific allergen. The antibodies circulate through your body on white blood cells (basophils) that pass into all your body tissues where they bind to immune system cells, called mast cells.
Both basophils and mast cells produce, store, and release histamine, which causes the symptoms - itching, swelling, hives - associated with reactions. (That's why some allergy pills are called antihistamines.) When the antibodies carried by the basophils and mast cells come in contact with food allergens, boom! You have an allergic reaction.
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Allergy linggo
allergen. Any substance that sets off an allergic reaction.
anaphylaxsis: A potentially life threatening allergic reaction that involves many body systems.
antibody: A substance in your blood that reacts to an antigen.
antigen: A substance that stimulates an immune response; an allergen is an antigen.
basophil: A white blood cell that carries lgE and releases histamine.
ELISA: Short for enzyme linked immunosorbent assey; a trait used to determine the presence in your blood of antibodies, including antibodies to specific allergens.
histamine: The substance released by the immune system that provides symptoms or an allergic reaction such as itching and swelling.
intolerance: A nonallergic adverse reaction to food.
lgE: An abbreviation for immunoglobulin E, the antibody that reacts to allergens.
mast cell: A cell in body tissue that releases histamine.
RAST: An abbreviation for radioallergosorbent test, a blood test used to determine whether you are allergic to certain foods.
urticaria: The medical name for hives.
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Who gets food allergies?
A tendency to allergies (though no the particular allergy itself) is inherited. If one of your parents has a food allergy, your risk of having the same problem is two times higher than it would be if neither of your parents were allergic to foods. If both your mother and your father have food allergies, your risk is four times higher. People with food allergies are often allergic to other things, such as dust or pollen, as well.
Are food allergies dangerous?
They can be. While most allergic reactions are unpleasant but essentially mild, about 100 people die every year in the United States from an allergic reaction to food. These people have suffered anaphylaxsis, a rare but potentially fatal condition in which many different parts of the body react to an allergen in food (or some other allergen), creating a cascade of effects beginning with sudden, severe itching and moving on to swelling of the tissue in the air passages that can lead to breathing difficulties, falling blood pressure, unconsciousness, and death.
Identifying a Food Allergy
If you sprout hives or your skin itches or your eyelids, lips, and tongue begin to swell right after you've eaten a particular food, that's a clear sign of a food allergy. But some allergic reactions occur in milder form, many hours after you've eaten. To identify the culprit, your doctor may suggest an elimination diet.
This regimen removes from your diet foods known to cause allergic reactions in many people. Then, one at a time, the foods are added back. If you react to one, bingo! That's a clue to what triggers your immune response.
To be absolutely certain, your doctor may "challenge" your immune system by introducing foods in a form (maybe a capsule) that neither you nor he can identify as a specific food. This rules out any possibility that your reaction has been triggered by emotional stimuli - that is, seeing, tasting, or smelling the food.
Two more sophisticated tests - ELISA (enzyme linked immunosorbent assayJ) and RAST (radioallergosorbent test) - can identify antibodies to specific allergens in your blood. But these two tests are rarely required.
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Elimination Diet
Because different people are sensitive to different foods, more than one elimination diet exists. The three listed here eliminate broad groups of foods known to cause allergic reactions in many people. Your doctor will pick the one that seems most useful for you.
Diet #1: No beef, pork, poultry, milk, rye, corn
Diet #2: No beef, lamb, rice, milk
Diet #3: No lamb, poultry, rye, rice, corn, milk
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Coping with food allergies
Once you know that you're allergic to a food, the best way to avoid an allergic reaction is to avoid the food. Unfortunately, the task may be harder than it sounds.
Some allergens are hidden ingredients in dishes made with other foods. For example, people allergic to peanuts have suffered serious allergic reactions after eating chili made with peanut butter. Rye bread may contain some wheat flour, which contains gluten, a protein that is a common food allergen.
Another problem is that you may not even have to eat the food to suffer an allergic reaction. People who react to seafood - fin fish and shellfish - are known to have developed respiratory problems after simply inhaling the vapors or steam produced by cooking the fish.
If you are a person with a potentially life-threatening allergy to food (or another allergen, such as wasp venom), your doctor may suggest that you carry a syringe pre-filled with epinephrine, a drug that counteracts the reactions. You may also wish to wear a tag that identifies you as a person with aserious allergic problem. One company providing these tags is Medic-Alert, a 40 year old firm located in Turlow, Ca. The telephone number is 1-900-633-4260.
The food industry takes food allergies so seriously that the National Restaurant Association has joined forces with the American Academy of Allergy, Asthma, and Immunology; the Food Allergy Network, and the International Food Information Council Foundation to keep people informed about food allergies.
You may want to visit the Web sites of the Food Allergy Network(http://www.Foodallergy.org) and the International Food Information Council Foundation (http://ificinfo.health.org) for more details on food allergies.
Foods most likely to cause allergic reactions
Here's something to chew on: Almost three quarters of all allergic reactions to food are caused by just three foods - eggs, milk, or peanuts. Of the three peanut allergies seem to be the most common - or at least peanut allergy cases make the newspapers most often.
People allergic to peanuts may break out in hives just from touching a peanut or peanut butter and suffer more serious reactions after imply tasting chocolate made in a factory where it had touched machinery that had previously touched peanuts.
Here is a list of 12 foods most likely to set off an allergic reaction.
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Berries, chocolate, corn, eggs, fish, legumes, milk, nuts, peaches and their relatives, pork, shellfish, and wheat.
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Other Body Reactions to Food
Allergic reactions aren't the only way your body registers a protest against certain foods.
Food intolerance is a term used to describe reactions that are common, natural, and fenitely not allergic, which means that these reactions do not involve production of antibodies by the immune system. Some common food intolerance reactions are:
A metabolic food reaction, which is an inability to digest certain foods, such as fat or lactose (the naturally occurring sugar in milk). Metabolic food reactions can produce gas, diarrhea, or other signs of gastric revolt and are an inherited trait.
A physical reaction to a specific chemical such as the laxative substance in prunes or mono sodium glutamate (MSG), the flavor enhancer commonly found in Asian food. While some people are more sensitive that others to these chemicals, their reaction is a physical one, not an allergy.
A body response to psychological triggers. When you are very fearful or very anxious or very excited, your body moves into hyperdrive, secreting hormones that pump up your heartbeat and respiration, speed the passage of food through your gut, and cause you to empty your bowels and bladder. The entire process called the "fight or flight" reaction, prepares your body to defend itself by either fighting or running. On a more prosaic level, a strong reaction to your food may cause diarrhea. It's not an allergy; it's your hormones.
A change in mood and/or behavior. Some foods, such as coffee, contain chemicals, such as caffeine, that have a real effect on mood and behavior, but that's for another blog. ~ Aunt Millie
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