TITLE: Peanut Allergies
AUTHOR: Nicole Starr
DATE: 5/13/09
Peanut allergies are the most predominant food allergy in the United States infecting 1.5 million people. This topic is of interest to me because one of my good friends has lived with a peanut allergy for the majority of her life. She has had many close encounters with peanuts before as well as a fair share of allergic reactions, fortunately none being too serious. I chose this topic in hopes learn more about the mechanism of peanut allergies as well as the preventative measures that one must take to in order to avoid contact with this particular allergen. Research regarding this allergen is on the rise due to an increase in allergic reactions to peanuts. The most current research being studied and tested is oral immunotherapy, sublingual therapy, as well as herbal formulas.

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Statistics in a Nutshell:

  • Most prevalent food allergy in the U.S. affecting 1.5 million people
  • Most common cause of food related death due to anaphylaxis (approx 100 people die/year)
  • 15,000 people/year go to emergency room for allergic reactions
  • 8% of children under 6 years old have food intolerance & 2-4% have food allergy
  • 25% children with will outgrow their peanut allergy
  • Peanut allergies has doubled in children over 5 year period (1997-2002)
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What is a Peanut Allergy?

Peanuts come from the legume family and are more closely related to peas, beans, and soy than other nuts. The majority of people who are allergic to peanuts can tolerate other foods within the legume family. When people develop a peanut allergy they are not allergic to the peanut itself, but rather the protein that is embedded in the peanut. A peanut allergy is considered to be a disease because for most the allergy will last a lifetime. Allergic reactions due to peanuts can range from being a minor irritation to becoming life threatening, such as anaphylaxis.
"Food allergens (the food fragments responsible for an allergic reaction) are proteins within the food that usually are not broken down by the heat of cooking or by stomach acids or enzymes that digest food. As a result, they survive to cross the gastrointestinal lining, enter the bloodstream, and go to target organs, causing allergic reactions throughout the body" (Muth,166).

Mechanism of Action:
Peanut allergies usually develop early on during a person's life. It effects a person's immune system due to the proteins found in peanuts. The first time that a person is exposed to a peanut a reaction does not occur. However, when exposed again to peanuts an allergic reaction occurs due to antibodies that have been built up to protect the body from the protein that is in the peanut. If a person with a peanut allergy ingests a peanut, then the protein within the peanut will get absorbed and enter the bloodstream causing thousands of IgE antibodies to attach to mast calls and basophils. Theses cells will then release histamine which triggers an allergic response, such as sneezing or skin irritations. Our immune system is intended to protect us from infection and disease and not to hurt us. A person's immune system who has a peanut allergy mistakes the proteins in peanuts as something harmful signaling the body to attack these proteins. When a person experiences a food allergy it represents a strong, misdirected immune response.
"A person who has a tendency to develop allergies tends to produce increased amounts of IgE. After the initial exposure to a specific allergen (such as 'cat' or 'dog' protein) the body reacts to future exposures by creating millions of IgE antibodies. These newly produced IgE antibodies then connect to special blood cells called basophiles, and special tissue cells called mast cells. These cells are then 'stimulated' to release histamine which causes the allergy symptoms: Itchy watery eyes and nose, scratchy throat, rashes, hives, eczema, and even life-threatening anaphylaxis" (Muth, 178).
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Allergy vs. Intolerance:
  • Allergy- Occurs when the bodies immune system recognizes an allergen (protein found in food) as foreign and then produces antibodies for protection. Histamine is then released, causing an allergic reaction.
  • Intolerance- Occurs when there is a problem with the bodies metabolism and has nothing to do with the immune system. If a person is intolerant to peanuts then they won't be able to digest them properly, resulting in stomach aches.
Researches aren't quite sure of the exact cause of peanut allergies, but it is thought to be hereditary. If one parent suffers from a food allergy of any kind then the likelihood of their offspring developing a food allergy is a little under 50%. If both parents have food allergies then the likelihood of their children developing a food allergy has increased to about 70%. Peanut allergies are first discovered at a young age and for most will last a lifetime. Only about 25% of children who have peanut allergies will outgrow them by adulthood. Food allergens can be prevalent even before a person is born as well as in a mother's breast milk.
"Both food and environmental allergens can be detected in breast milk. The body's immune system and digestive processes are designed so that the infant is exposed to the foods the mother ingests. This raises the possibility, at least theoretically, that there is a reason foods ingested by the mother are passed into breast milk and, therefore, the baby is exposed to these proteins" (Sicherer,261).
There have been arguments for and against avoiding peanut containing foods while pregnant or nursing. Some believe that people should avoid eating any products that contain peanuts while pregnant or nursing because it might trigger an allergic reaction in the child later on, especially if the parents have a history of food related allergies. While others believe that it is crucial for the mother to eat various peanut containing products in order to expose their offspring to the proteins found in peanuts as well as build up their immune system to recognize these proteins as being harmless. More research needs to be done on the subject in order to determine the right approach to follow.
Another theory regarding why people develop peanut allergies is that they are producing too much IgE antibodies. "Part of the fault may lie in modern medical practices: with antibiotics and immunizations to protect against micro-organisms and parasites, children's immune systems may be getting weaker and even board, with little or nothing to fight" (Park, 43). This could be a result of the hygiene hypothesis which states that allergic diseases are less common in children from larger families. People in large families are exposed to more infectious agents, such as allergens though siblings. There is said to be an increase in allergies due to the fact that people are having less children, who are not being exposed to allergens, such as peanuts causing a weakened immune system.
A standard peanut contains about 200mg of protein. In extreme cases some people may be allergic to only 1% of a peanut, while others can eat a peanut and only suffer from a minor allergic reaction. The amount of peanuts ingested to trigger an allergic reaction will vary depending upon the person and each person may experience different magnitudes each time an allergic reaction occurs.
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An allergic reaction to peanuts can occur within minutes after exposure. For some the reaction is mild and others might experience a more severe and in some instances life-threatening reaction.
Examples of Symptoms of an allergic reaction that are not intrinsically life threatening:
  • Breathing- Nasal congestion, runny nose,occasional cough
  • Gastrointestinal- Nausea, vomiting, diarrhea, abdominal pain, itchy mouth, lip swelling , odd taste in mouth
  • Skin- Flushing/red skin, itch, hives, skin swelling, eczema flare
  • Other- Red/ itchy eye, uterine contractions
Examples of symptoms of an allergic reaction that are or may soon become life threatening:
  • Respiratory- Throat tightness, wheezing, shortness of breath, repetitive coughing, trouble breathing, high-pitched noises when air goes in and out, change in voice/hoarseness, turning pale/blue
  • Gastrointestinal- obstructive tongue swelling, trouble swallowing
  • Cardiovascular- low- blood pressure, fainting, passing out, losing consciousness, chest pain, dizzy/lightheaded, weak pulse
  • Other- feeling of "impeding doom"
(Sicherer, 14-15)
Anaphylaxis occurs when there is a severe allergic reaction. It is a multi-organ reaction that is associated with IgE hypersensitivity. Anaphylaxis can cause a sudden drop in blood pressure that can be fatal if not treated immediately. Anaphylaxis is usually treated with epinephrine, which is adrenaline that is injected into the body that will constrict blood vessels and cause a persons blood pressure to increase.

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Prevention & Treatment:
One of the main and most obvious ways to prevent an allergic reaction from occurring is to avoid peanuts altogether. This is a hard thing to do because peanuts are everywhere and are in many of the foods that we eat. There are many foods that one should avoid if they suffer from a peanut allergy.

Common Foods

Peanut butter & peanut flour
Ground or mixed nuts
Grain breads
Energy bars
Salad dressing

Exposure to peanuts can occur through direct contact, cross-contact, or inhalation. Direct contact occurs when a person ingests a peanut or when the peanut protein is administered through the skin, as in the case of an allergy shot. Cross-contact can occur if foods were processed in the same machines that had previously processed a peanut product, which tends to happen quite often. It becomes ever so important to read food labels for peanut containing products. By law it is required for companies to state whether their product was manufactured in a place that contains peanuts in order to help prevent allergic reactions from occurring. There is always the possibility that one might inhale traces of peanut protein that might trigger an allergic reaction.
Peanuts have been banned from many schools and airlines in attempts to safeguard the people who suffer from peanut allergies. It has gotten to the extreme that some airlines now have peanut- free zones. "In some instances, peanut-free zones seem downright silly. Upon request, Delta and Northwest airlines will set up a peanut-free buffer zone spanning three rows in front of and behind an allergic passenger" (Park, 44). More and more people are becoming aware of peanut allergies and are going to great lengths in order to prevent people from having an allergic reaction.
If a person is allergic to peanuts it is important for them to carry an EpiPen (epinephrine) with them just in case they have an allergic reaction. People need to be be given the proper information about when and how to inject an EpiPen if needed. What is alarming is that many people with peanut allergies don't have an EpiPen readily available to them. If a person has an allergic reaction they should report it to their doctor as soon as possible. There are a couple of tests that one could do to determine if in fact they have a peanut allergy.
  • Skin prick test - The proteins inside the peanut are injected beneath the skin. Upon injection if a small bump develops this indicats that the person is allergic to peanuts.
  • Blood test- This looks for and measures the amount of IgE antibodies concentrated in the bloodstream.

Current Research:

Oral Immunotherapy
This is a new therapy that researchers are working on to help people better tolerate peanuts. "In a new strategy called oral immunotherapy, doctors try to retrain the immune system by hitting it with the offending protein enough times, in increasing doses that the body's defenses eventually relent and accept the protein as friend rather than foe" (Park, 44). Under a high level of medical supervision children were given a small amount of peanuts for two years. Most of the children who participated were able to tolerate peanuts after gradually being exposed to them.
Slowly building up the amount of peanuts that were given to children caused a change in their immune systems to where their bodies were able to tolerate peanuts instead of experiencing an allergic reaction. Oral immunotherapy is not a cure, it just helps people with peanut allergies have a tolerance for the protein found in peanuts. In order to keep that tolerance a person must consume peanuts on a daily basis. Children that have participated in oral immunotherapy have been able to tolerate up to fifteen peanuts a day without having an allergic reaction. For now the only way to conquer the peanut allergy is to build up a person's tolerance to the proteins found in peanuts.

Allergy Shots
This is a type of immunotherapy where a person is injected with the same protein found in a peanut that triggers an allergic reaction. There was no success in this research, most of the people injected with the protein experienced a severe allergic reaction. Researchers believe allergy shots to be ineffective because the protein is injected directly into the bloodstream, causing IgE antibodies to attach to mast cells, which will then release histamine causing an immediate response. Whereas, oral immunotherapy has been proven on many accounts to be very effective because a person is ingesting the peanut, therefore taking a longer time for the proteins to be taken up into the bloodstream causing an allergic response.

Sublingual Therapy
This type of therapy is when drops of peanut proteins that trigger an allergic reaction are placed under the tongue where they then can be absorbed into the bloodstream. "Ear, nose, and throat resident Kevin Lollar is leading a trial of sublingual immunotherapy for food allergies at the University of Missouri. Not approved in the USA, the treatment has been used for more than a decade in Europe for inhaled allergies and 'shown to be much safer than shots', says Lollar" (Rubin, 13). Like oral immunotherapy, sublingual therapy gradually introduces the peanut proteins into the bloodstream, thus lowering the risk of a deadly reaction.

Food Allergy Herbal Formula-2

This is based on a 2000- year old Chinese remedy. This is a type of pill that does not contain any food allergen. Instead it consists of a combination of botanicals, such as ginseng and oil made from cinnamon tree bark. It is currently being tested on people with peanut allergies.
Photo Courtesy of allergicchild.com/peanut_allergy

Peanut allergies are the most common food allergy that continues to be on the rise. Some say that it has even doubled over the last five years, due to a variety of reasons. "The prevalence might be increasing in developing countries, which are undergoing rapid economic growth with subsequent decrease in family size and increase in hygiene. It is postulated that the decreasing microbial burden influences the immune system by shifting toward a TH2 cell response, which is responsible for triggering allergic disorders (ie, hygiene hypothesis)" (Ben-Shoshan, 787). It is also shown that the gradual increase of peanuts given to a person with a peanut allergy is associated with a decrease in peanut allergy prevalence, making the child able to tolerate peanuts better. Now that the mechanism of peanut allergies is known it is only a matter of time before researchers find a cure ridding many people free from this childhood curse.



Ben-Shoshan, Moshe et.al. "Is the Prevalence of Peanut Allergy Increasing? A 5-Year Follow-Up Study in Children in Montreal." Journal
of Allergy and Clinical Immunology. 123.4 (2009): 783-788.

Best, Angie. "New Therapy May Knock Out Peanut Allergy." PeanutAllergy.com. 2009. Duke University Medical Center. March 16, 2009.

Muth, Annemarie S. Allergies Sourcebook. Detroit: Omnigraphics, 2002.

Park, Alice. "Going Nuts Over Nut Allergies." Time Magazine. 9 Mar. 2009: Society, 42-45.

Rubin, Rita. "Finally, Hope on Horizon for a Childhood Curse." USA Today. 22 Apr. 2009: News, 01a.

Sicherer, Scott H. Understanding and Managing Your Child's Food Allergies. Baltimore, The John Hopkins University Press, 2006.

Tortora, Gerard et. al. Microbiology: An Introduction. San Francisco: Benjamin Cummings, 2007.