1. Food Allergies

2. What is a food allergy?
An immune reaction that occurs after eating a certain food
Also known as a food hypersensitivity
Autoimmune disease
Elicits an abnormal immune response to a harmless food substance
Antibodies are released to fight the allergen
Allergen is usually a protein
A food allergy is also known as food hypersensitivity and occurs when a normally harmless food elicits an immune response to the allergen, usually a protein. This immune response involves the release of antibodies to fight the allergen, usually a protein, and in turn this immune response brings upon the symptoms of food allergy.

3. Classification of Allergies
Allergic reactions are classified into non-IgE-mediated, IgE-mediated or mixed response
Non-IgE
Slower in onset, primarily gastrointestinal reactions
IgE mediated
Causes histamine and other chemicals to be released which trigger allergy symptoms
Rapid in onset, symptoms include anaphylaxis & urticaria
Allergic or immunological reactions are classified into IgE-mediated and non-IgE mediated reactions. IgE is an antibody that is formed by the immune system in response to a substance that the body deems harmful. IgE antibodies elicit an immune response, causing histamine and other chemicals to be released and cause the symptoms of an allergy. If the response occurs several hours or a few days after consuming the food, it is most likely a non-IgE response which typically involves gastrointestinal symptoms such as nausea or stomach cramping. Typically, IgE-mediated reactions occur a few minutes to within an hour of consumption and these symptoms include anaphylaxis and urticaria. Anaphylaxis is an acute, potentially life-threatening hypersensitivity reaction defined by a number of signs and symptoms ranging from coughing, airway constriction, abdominal pain or faintness to chest pain and the loss of consciousness. It can range from mild to severe. Most cases are mild but any anaphylaxis has the potential to become life-threatening. Urticaria is a skin rash usually accompanied by swelling and itching.

4. Gastrointestinal Tract
Symptoms
Allergy symptoms can occur seconds to hours after ingestion of the allergen
Most common symptoms:
swelling, sneezing, nausea, GI distress
Skin
Swelling of lips, tongue & face
Itchy eyes
Hives
Rash
Respiratory Tract
Itching or tightness of throat
Shortness of breath
Dry or raspy cough
Runny nose
wheezing
Gastrointestinal Tract
Abdominal pain
Nausea
Vomiting
diarrhea
Symptoms of food allergies vary between individuals but the most common are swelling, sneezing, nausea, digestive problems, hives or swollen airways. Others include itchy eyes, hives, skin rash, tightness of the throat, shortness of breath, runny nose, abdominal pain, nausuea, vomiting and diarrhea.

5. Foods most commonly associated with allergic reactions

6. Frequently allergenic foods
Most common food allergies in young children:
Most common food allergies in older children & adults
Milk (casein, whey)
Fish
Eggs
Wheat (gluten)
Soy
Peanuts
Tree nuts
Shellfish
Milk, eggs, wheat and soy are frequent allergies that many children have but will grow out of. On the other hand, an allergy to peanuts, tree nuts, fish and shellfish tend to be lifelong conditions.

7. Food Allergy vs Food Intolerance
Reactions to food consist of a variety of reactions to food or food additive ingestion
Usually not allergenic and caused by food intolerance
Symptom-inducing food properties
Metabolic disorders
Bacterial food contamination
Adverse food reactions consist of a variety of responses to food or food additives that are consumed. The majority of these responses are not allergenic but caused by food intolerance caused by particular food properties such as caffeine-causing irritable bowel syndrome, metabolic disorders such as lactose intolerance resulting from a lack of an enzyme to break down lactose in milk or food contaminated with bacteria. Psychological reactions to food can also lead to the belief of the prevalence of a food allergy. Even though about 25% of adults think they have an allergy, only 1-2% of adults and 5% of children are truly affected.

8. Variability in Prevalence
Determination of the exact prevalence is difficult
Considerable variation in data collection
Self-reporting,
physician assessment,
skin tests, IgE levels
However, self-reports indicate that food allergy incidences are on the rise
Food allergy in infants are most common
Determination of the exact prevalence of food allergies is complicated because there is considerable variation in data collection. Reports are based on self-reported questionnaires, physician assessment, skin tests and/or IgE levels that are confirmed by double-blind placebo-controlled challenges. However, many do not distinguish between IgE and non-IgE mediated responses. In general, food allergy manifests most commonly in infancy, peaking at 1 year of age and diminishing by age 3. Infants are more susceptible to food allergies because they have a decreased number of enzymes to break down proteins, low antibody levels, relatively low pH and an immature gut barrier.

9. This chart from the Center of Disease Control and Prevention (CDC) shows the growing trend of reported allergies from an average of 2,615 between each year 1928 and 2000 to over 9,500 each year between 2004 and It is not well understood why this increase has occurred.

10. Increased Exposure
Development of an allergy depends on the structure of the protein, dose of the antigen and the genetic susceptibility of the host
Non-oral exposure may be a primary risk factor
Damaged skin may allow increased exposure before tolerance has been developed through oral ingestion
There are several hypotheses about the rising prevalence of food allergy. Development of an allergy depends on the structure of the protein, the dose of the antigen and the genetic susceptibility of the host. Oral exposure to low doses of a protein may induce sensitization whereas high doses may result in tolerance. This is pertinent to those who encounter accidental exposures to the allergens in protein as it may be potentially harmful. Conversely, non-oral exposure may be a primary risk factor as damaged skin may allow increased exposure before tolerance has been developed through oral ingestion.

11. PEANUT Food Allergies Milk Egg Tree Nuts Fish Shellfish Wheat Soy
Food allergy to peanuts is the most common, but other foods such as milk, egg, tree nuts, fish, shellfish, wheat, and soy are also known to cause allergic reactions in some people. The majority of this presentation will focus on the peanut allergy.

12. Peanut Allergy Peanut sensitization does not conclude an allergy
About 95% of sensitized individuals are not clinically allergic
Attracted the most attention because it is relatively common, typically permanent and often severe
Significantly increased globally in the past decade
2-3x as common
It has been shown that many individuals may have developed sensitization to peanuts but only 95% of those are diagnosed as clinically allergic. Peanut allergy has attracted the most attention because it is relatively common, typically permanent and often severe. It has significantly increased globally in the past decade and is now 2-3 times more common than other food allergies.

13. Peanut Allergy Hygiene Hypothesis
Antibiotic treatment increased ease of peanut sensitization
Studies from many countries show that early exposure of viral infection may produce a proactive effect
Children born into families with several siblings tend to have a reduced frequency of allergic sensitization
One common cause attributed to the increase in this particular allergy and for the rise in allergy incidences in general is the hygiene hypotheses. The hygiene hypothesis originated from epidemiologic observations relating exposure to other children to a reduced risk of allergy. It has been hypothesized that our society’s knack for cleanliness has attributed to the rise in food allergies. Studies from many countries show that early exposure of viral infections may produce a proactive effect against the sensitization of allergens and others conclude that babies born into families with many children are less inclined to develop allergies; this finding has been confirmed in a day-care setting. Conclusions regarding the relevance of these incidences should be drawn with care and the questions of which germs, at what time and at what price should be taken into consideration.

14. Peanut Allergy Processing
Allergenic protein content depends on processing and varies by brand
Higher allergenic protein content:
More mature, larger kernels
Drying or curing at higher temperatures
Roasting
Whipped or emulsified peanut butter
Less allergenic protein content:
Small kernels
Raw peanuts
Highly processed oils had no detectable protein
It is generally advised that peanut-allergic patients avoid all peanut oils
The intake of peanuts in countries of China and Southeast Asia are comparable to that in the United States but the frequency of peanut allergy is significantly less. Thus, another hypothesis for the increase of peanut allergy in the US is that processing of peanuts may play a role. The protein composition has been found to be pretty consistent around the world but harvesting and processing may have a profound effect on the allergenic properties. The quantity of allergenic protein in peanuts can vary extensively with processing and handling techniques. More mature, larger kernels tend to have a higher allergenic protein content than smaller kernels and processing at high heat tends to increase the allergenic protein as well. It has been shown that peanuts roasted 10 minutes have 22x higher allergenic protein content than raw peanuts. In the United States, the consumption of peanuts with these allergenic-inducing techniques are far more common than in China or Southeast Asia where peanut allergy is less prevalent.

15. Peanut Allergy Age of Introduction
Sensitization to peanuts typically occurs at an early age, therefore such patients are more likely to react at first exposure
No conclusive evidence has been found to support the theory that the allergy is developed in utero
Food allergy manifests most commonly in infancy, peaking at 1 year of age and declining by age 3
Recommendations only in place for at-risk infants
Sensitization to peanuts typically occurs at an early age. With % of peanut-allergic children being reported to react to the first known exposure, it has been suggested that sensitization has occurred before birth. However, no peer reviewed studies that assessed the impact of dietary exposure to peanuts and the subsequent development of allergy to peanuts in the offspring were found. Food allergies first occur most commonly in infancy, peaking at 1 year of age and declining by age 3. This may result from decreased enzymes to digest proteins, low IgA antibody levels, relatively low pH and an immature gut barrier. The American Academy of Pediatrics currently only has recommendations in place for the mothers of at-risk infants to avoid allergenic substances while pregnant, lactating and until the child is 3 years of age.

16. Milk Allergy 2.5% of children younger than 3
Develops in first year of life
Most children will outgrow it
Baby Formula
Hidden Sources: deli meats, non dairy items, canned tuna fish, restaurant foods and sauces
Approximately 2.5% of children younger than 3 are allergic to milk. Nearly all infants who develop an allergy to milk do so in their first year of life. Most children who have milk allergy will outgrow it in the first few years of life. Baby formula is often the source of the first allergic reaction to milk. There are baby formulas on the market that have extensively broken down milk protein or soy based formulas which will often be recommended by a physician for a child with a milk allergy. Some hidden sources of milk may be deli meats if the meats were sliced on the same meat slicer as cheese, non dairy items where the milk protein casein may be used as a binder such as some canned meats and some canned tuna. Reading the food label is the best way to understand if milk or casein is contained in the product. Restaurant foods should always be questioned as butter, sour cream, milk and cream are frequently used to enhance the flavors and texture of food.

17. Egg allergy Affect approximately 1.5% of young children
Likely to be outgrown
Most allergic reactions associated with egg involve the skin
Hidden sources: coffee drinks with foam topping, soft or hard pretzels, cooked pasta, egg substitutes.
Vaccines
Egg allergy is estimated to affect about 1.5% of young children but it’s also one of the most likely to be outgrown over time. Most allergic reactions associated with egg involve the skin, but anaphylaxis, which is a serious allergic reaction that has a rapid onset and may cause death, can also occur. Allergic reactions to egg are mostly IgE-mediated which involve IgE antibodies. Some hidden sources of egg are coffee drinks that are made with a foam topping as some of these frothy foam toppings use whipped egg whites. Soft or hard pretzels sometimes use an egg wash before salted to make the salt stick to the pretzels. Commercially cooked pasta will sometimes contain egg but most dry pastas do not. Egg substitutes will also sometimes contain egg whites. Reading the food label is the best way to determine if the food contains eggs. Finally, some vaccines are grown inside eggs so be sure to ask your physician if the vaccines your child is to receive have been processed using eggs. The influenza vaccine is commonly grown in eggs and does contain egg protein and in turn will likely produce an allergic reaction to someone with an egg allergy.

18. Tree nut allergy 1.8 million Americans
Allergic are among the leading causes of fatal and near-fatal reactions to foods
Tree nuts = walnuts, almond, hazelnuts, coconuts, cashews, pistachios, and Brazil nuts
Tend to have a lifelong allergy
Hidden sources: Salads and salad dressing, barbecue sauce, breading for chicken, pancakes, meat-free burgers, pasta, honey, fish dishes, pie crust, mandelonas (peanuts soaked in almond flavoring), mortadella (may contain pistachios)
An estimated 1.8 million Americans have an allergy to tree nuts. Allergic reactions to tree nuts are among the leading causes of fatal and near-fatal reactions to foods. Tree nuts include, but are not limited to, walnuts, almonds, hazelnuts, coconut, cashews, pistachios, and Brazil nuts. Tree nuts should not be confused or grouped together with peanuts, which are a legume, or seeds, such as sunflower or sesame.
Similar to those with peanut allergies, most individuals who are diagnosed with an allergy to tree nuts will likely to have a lifelong allergy. Some hidden sources of tree nuts include: salads and salad dressing, barbecue sauce, breading for chicken, pancakes, meat-free burgers, pasta, honey, fish dishes, pie crust, mandelonas (peanuts soaked in almond flavoring), mortadella (may contain pistachios).

19. Fish and shellfish allergy
2.3% of Americans
Salmon, tuna, and halibut
Avoid all varieties
Lifelong
Avoid seafood restaurants
Asian restaurants-fish sauce
Read ingredient lists
Avoid areas where fish is being handled or cooked
Hidden Sources: Salad dressing, Worcestershire sauce, bouillabaisse, imitation fish or shellfish, meatloaf, barbecue sauce (some are made from Worcestershire)
An estimated 2.3% of Americans report allergy to seafood, including fish and shellfish. Salmon, tuna, and halibut are the most common kinds of fish to which people are allergic. It is generally recommended that individuals who are allergic to one species of fish or shellfish avoid all varieties. Fish and shellfish allergy is considered to be a lifelong allergy as once a person develops the allergy, it is very unlikely they will lose it. To avoid a reaction, strict avoidance of seafood and seafood products is essential. It is recommended to avoid seafood restaurants even if you plan to order a non-seafood dish from the menu. Asian dishes often include a fish sauce, so avoiding Asian dishes while eating out is also recommended. Always read ingredient labels to identify fish and shellfish ingredients. In addition, avoid touching fish and shellfish, going to the fish market, and being in an area where fish or shellfish are being cooked.

20. Wheat allergy Common in children Often confused with celiac disease
IgE-mediated response to wheat protein
May tolerate other grains
Symptoms range from mild to severe
Sources: baked goods (wheat flour), pasta, sauces thickened with flour, cereals, crackers
Substitute with amaranth, barley, corn, oat, quinoa, rice, rye, tapioca
Wheat allergy is primarily common in children, and is usually outgrown before reaching adulthood. Wheat allergy is sometimes confused with celiac disease, which is a digestive disorder that creates an adverse reaction to gluten. Individuals with celiac disease must avoid gluten, found in wheat, rye, barley, and sometimes oats. People who are allergic to wheat have an IgE-mediated response to wheat protein and may tolerate other grains. Symptoms of a wheat allergy reaction can range from mild to severe.
Sources of wheat are in most baked goods which presents a challenge to those trying to avoid it as wheat is the nation’s predominant grain product. Someone on a wheat-restricted diet can eat a wide variety of foods, but the grain source must be something other than wheat. Alternate grains such as amaranth, barley, corn, oat, quinoa, rice, rye, and tapioca are often tolerated by someone with a wheat allergy.

21. Soy allergy More common food allergies in babies and children
Major ingredient in food products
Hard to avoid
Dietitian should be consulted
Symptoms typically mild
Hidden sources: baked goods, canned tuna, cereals, crackers, infant formulas, peanut butter, sauces, and soups.
Typically can tolerate soybean oil
Soybeans have become a major part of processed food products in the United States. Avoiding products made with soybeans can be difficult as they are often not noticeable as a soybean within the product. Soybeans alone are not a major food in the diet but, because they're in so many products, eliminating all those foods can be very tough. Symptoms of soy allergy are typically mild, although anaphylaxis is possible. Soybean allergy is one of the more common food allergies, especially among babies and children. Food sources of soy can include baked goods, canned tuna, cereals, crackers, infant formulas, peanut butter, sauces, and soups. Most people with a soy allergy can however, typically tolerate soybean oil as the protein (which is the allergen) in soybean oil is removed during processing.

22. Can some individuals be allergy-prone?
Patients reacting to greater numbers of allergenic epitopes experienced more severe allergic reactions & to smaller doses
Children with egg &/or milk allergies more susceptible
Peanut-allergic patients do not usually react to other legumes such as green beans, lima beans, navy beans
95% of peanut-allergic patients can tolerate soy
It is currently unknown if some individuals can be allergy prone. Patients reacting to greater numbers of allergenic epitopes experience more severe allergic reactions & tend to react to smaller doses. Many children who have milk and egg allergies are potential candidates for developing allergies to other highly sensitizing foods such as peanuts during childhood. However, people who have a peanut allergy do not usually react to other legumes such as green beans, lima beans or navy beans and are also likely to tolerate soy. This shows that some individuals are genetically more susceptible to develop food allergies.

23. treatment options
Now let’s examine some treatment options for food allergies.

24. Curing Food Allergies There is currently no cure for food allergies
The current recommendation is to avoid the allergen
Promising treatments on the way
There is currently no cure for food allergy and the American Academy of Pediatrics and the Food and Drug Administration advise those with the condition to completely avoid the susceptible foods. However, there are several promising treatments in the process of development or in testing. Next, we will look at three of these options.

25. Immunotherapy Sublingual immunotherapy (SLIT) Oral Immunotherapy (OIT)
Contact of an antigen induces tolerance
Patient is given increasing amounts of the allergen
Conclusion: may be effective during therapy (for egg, milk and hazelnut) but there is no evidence for long-term tolerance
The first is, sublingual immunotherapy and oral immunotherapy are based on the concept that contact of an antigen with the oral mucosa and gut-associated lymphoid system leads to tolerance. With these treatments, patients are given minute amounts of allergen orally and over time the quantity is increased. Only a few uncontrolled trials have been reported and, although OIT and SLIT for egg, milk and hazelnut appear to provide desensitization during therapy long term tolerance has yet to be validated.

26. Anti-IgE Therapy TNX-901 was given in varying doses
450 mg dose significantly increased threshold of reactivity to peanuts from 178 mg (about ½ a peanut) to 2.8 g (about 9 peanuts)
Enough to protect against accidental ingestions
Results were inconsistent
Would require bimonthly or monthly injections for rest of patients’ life
Conclusion: May be of use in severe cases
The second treatment option we will examine is the Anti-IgE Therapy. In one research study on peanut allergy treatment, TNX-901, an anti-IgE antibody, was administered to individuals in varying doses from 150 to 450 milligrams each week for four weeks. Results showed that the 450-mg dose significantly increased the threshold response from about ½ of a peanut to 9 peanuts, on average. The increased threshold would be enough to protect against accidental ingestions of peanuts and potentially protect the patient from a life-threatening reaction. However, the results were inconsistent and the therapy would require bimonthly or monthly injections for life. Still, it may be useful for those who have severe reactions to peanuts.

27. Engineered Recombinant Protein
The three major allergenic proteins in peanut
Ara h 1, 2 & 3 were isolated
Necessary for binding with IgE
The recombinant proteins were significantly more effective at blocking symptoms
The modified Ara h 1, 2 & 3 proteins have been manufactured and are undergoing testing before application for FDA approval
The third treatment option we will examine is again for peanut allergy and is the engineered recombinant protein. The three major proteins that elicit an allergenic response have been isolated to identify the allergenic components of peanuts. The proteins have been modified to reduce their ability to bind with the IgE antibodies within the human body, therefore reducing the allergenic response. The recombinant proteins have been shown to be significantly more effective at blocking symptoms. This treatment is undergoing further testing before being submitted for an application for approval by the Food and Drug Administration.

28. Chinese Herbal Medicine
A 9-Herb preparation termed Food Allergy Herbal Formula (FAHF)-2 blocks anaphylactic symptoms
Provided full protection against symptoms in a clinical study performed on mice
The FDA has recently approved a botanical Investigational New Drug application
A phase-I clinical trial will soon be underway
Another treatment option that is being researched is the Food Allergy Herbal Formula (FAHF)-2. This herb blend contains 9 chinese herbs and has been shown to block anaphylactic symptoms and provide full protection against symptoms of peanut allergy in a clinical study performed on mice. The FDA has recently approved the application and a phase-I clinical trial will soon be underway.

29. Summary Comments
Food allergy is an autoimmune response often mistaken for food intolerance
Peanut allergy appears to be increasing
Genetic, environmental and immunological influences
Recent studies have led to improved diagnoses, management and patient education
Numerous approaches to treatment are underway
In summary, food allergies are an autoimmune response that is often mistaken for food intolerance. Research and reporting has found that the peanut allergy in particular appears to be increasing and theories as to why this is happening are still being examined. Genetic, environmental and immunological influences are being examined to explain how food allergies develop and many research studies are underway to find this answer. Improved diagnoses, allergy management and patient education have improved in recent years and foods that illicit allergic responses should be avoided. While a cure is not available, numerous treatment options are being examined. Reading food ingredient lists and asking questions about the foods you plan to consume are currently the best defense for those with food allergies.