|
Category Sitemaps
Diet
Food
Calories
Exercise
Losing weight
Weight loss help |
Food Allergies & Allergic Reactions to Foods
Today, over 12 million Americans have a food allergy. Over 6 million are
allergic to seafood. Food allergies are responsible for more than 30,000
emergency room visits each year. Approximately 3-4% of the adult population,
and 6-8% of children, have food allergies. The number of children with
peanut allergies has doubled over the past 5-year period.
Here are some Common Questions on Food Allergy
What is a food allergy?
There are times when your immune system decides that a particular food is
harmful and creates specific immunoglobulin E (IgE) antibodies to it. The
next time you eat that food, the IgE antibodies sense it and signal the
immune system to release massive amounts of chemicals (called "mediators")
and histamines. This is known as a food allergy. Your symptoms may include a
tingling sensation in the mouth, swelling of the eye lids, lips, tongue and
the throat, difficulty breathing, hives, vomiting, abdominal cramps, diarrhea, drop in blood pressure, loss of consciousness and rarely death.
Symptoms typically appear within minutes to two hours after you have eaten
the food to which you are allergic. A severe allergic reaction is called
anaphylaxis.
Any food has the potential to cause a reaction, but eight foods are
responsible for up to 90% of all food allergy reactions. These are milk,
eggs, peanuts, soy, wheat, tree nuts (such as almonds, pecans, Brazil nuts,
etc.), fish, and shellfish. Children generally are allergic to eggs, milk,
peanuts, and tree nuts. Adult allergies includes fish, shellfish, tree nuts,
and peanuts. People can also be allergic to fruits and vegetables. Rather
than the foods themselves, they have an allergy to fruit and vegetable
pollens and/or proteins.
A food allergy is NOT the same as
food intolerance. Intolerance to food
does not involve the immune system.
What am I allergic to?
Food allergy tests help identify or exclude specific foods as a cause of
your symptoms. Your doctor will decide what tests to perform and how to
interpret the results. Your doctor may put you on the elimination diet. You
replace foods that you think you might have an allergy to with other foods
that provide the same nutrients as those you've eliminated. Two to three
weeks later, your physician will have you gradually reintroduce the foods
you eliminated. If your symptoms return, it is probable that that particular
food is responsible for your food allergy. If you again eliminate the foods
that caused your symptoms and they clear up, most likely you are allergic to
that food. It is not a foolproof method and should be followed by more
sophisticated testing.
Your physician can determine what you are allergic to by doing a prick skin
test. Drops of suspected substances are placed on your forearm or back. The
skin is pricked by a needle, allowing a tiny amount of the substance to
enter the skin. If you are allergic to the substance, a small bump will form
at the site within 15 minutes.
Your doctor might decide on a radioallergosorbent test (RAST). You will have
to give a blood sample. A medical laboratory tests it with specific foods to
determine if IgE antibodies are present. You will get the results back in
about a week. A RAST is often used for young children or patients with skin
problems that make it difficult to accurately read the results of a prick
skin test. The results of either test are combined with your medical history
to determine whether a food allergy exists.
Both tests are reliable.
How careful must I be about the foods I buy?
You must check the ingredient labels for every food you intend to buy. If a
product doesn't have a label, you should avoid that food. Likewise, if a
label contains unfamiliar terms, ask for a clarification or avoid eating
that food. An ounce of prevention is worth a pound of cure: Stay away from
allergy-causing foods!
What should I do if I have an allergic reaction to food?
In most cases, you will need a shot of epinephrine. This is available by
prescription in injectable form, such as EpiPen® or Twinject®. You should
always have your prescribed medication, such as antihistamines or
epinephrine, available.
What research is being undertaken to better understand food allergies?
Although there is no cure for food allergies, research is promising.
Children can outgrow their food allergies, while adults don’t. In both
cases, peanuts, nuts, fish, and shellfish are usually lifelong allergies.
Physicians have learned that a decrease in sIgE levels over time helps
patients develop greater tolerance to milk and egg allergies. Researchers
found that roasted peanut protein inhibited digestive enzymes. Another study
looked at combining activated charcoal with peanut protein to prevent or
stop absorption in the stomach after accidental ingestion. Scientists have
found that the allergy to peanuts may have an environmental component.
Washing hands and tabletops with liquid soap, bar soap, or commercial wipes
removes the major peanut allergen, Ara h 1. Plain water and antibacterial
hand sanitizer, however, left detectable amounts of Ara h 1. Common
household cleaning agents, except dishwashing
liquid, removed peanut
allergen from table tops.
What is an
Intolerance to foods?
References
American Academy of Allergy, Asthma &Immunology. (no date). Do You have a
Food Allergy? URL:
http://www.foodallergy.org/downloads/DoyouhaveFA.pdf
Burks, Wesley. (2002). Food Allergies: Epidemiology. Medscape Today. URL:
http://www.medscape.com/viewarticle/535010?rss
Maleki SJ. et al. (2003). The major peanut allergen, Ara h 2, functions as a
trypsin inhibitor, and roasting enhances this function. Journal of Allergy
and Clinical Immunology. URL:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=12847498&dopt=AbstractPlus
Perry, T.T et al. (2004). Distribution of Peanut Allergen in the
Environment. Journal of Allergy and Clinical Immunology. URL:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=15131582
Shek, L.P. et al. (2004). Determination of Food Specific Ige Levels Over
Time can Predict the Development of Tolerance in Cow's Milk and Hen's Egg
Allergy. URL:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=15316521
Sicherer, S.H. et al. (2004). Prevalence of Seafood Allergy in the United
States Determined by a Random Telephone Survey. American Academy of Allergy,
Asthma &Immunology. URL:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=pubmed&dopt=AbstractPlus&list_uids=15241360
The Food Allergy & Anaphylaxis Network. (2006). Frequently Asked Questions:
What is a Food Allergy? URL:
http://www.foodallergy.org/questions.html
Vadas, P. (2003) Activated charcoal forms non-IgE binding complexes with
peanut proteins. Journal of Allergy and Clinical Immunology. URL:
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=12847495&dopt=AbstractPlus
|
|
