Imagine what it would be like if eating a peanut butter sandwich or some shrimp,
or drinking a tall glass of milk left you vomiting, gasping for breath, and
furiously scratching a fresh crop of hives. For some people with food allergies,
A food allergy, or hypersensitivity, is an abnormal response to a food triggered
by the immune system. While many people often have gas, bloating or another
unpleasant reaction to something they eat, this is not an allergic response.
Such a reaction is thought to not involve the immune system and is called "food
Only about 1.5 percent of adults and up to 6 percent of children younger than
3 years in the United States--about 4 million people--have a true food allergy,
according to researchers who have examined the prevalence of food allergies.
It's critical for people who have food allergies to identify them and to avoid
foods that cause allergic reactions. Some foods can cause severe illness and,
in some cases, a life-threatening allergic reaction (anaphylaxis) that can constrict
airways in the lungs, severely lower blood pressure, and cause suffocation by
the swelling of the tongue or throat.
An estimated 150 Americans die each year from severe allergic reactions to
food, says Hugh A. Sampson, M.D., director of the Elliot and Roslyn Jaffe Food
Allergy Institute at Mount Sinai School of Medicine in New York City and a food
The Food and Drug Administration's Center for Food Safety and Applied Nutrition
has made it a high priority to boost consumer and food industry awareness of
food allergens. As part of these efforts, the FDA is conducting food allergen
education programs for consumers and industry. The agency also is developing
a strategy for clear, easy-to-understand labeling of food allergens.
Food normally doesn't provoke a response from the human immune system, the
body's defense against microbes and other threats to health. In food allergies,
two parts of the immune response are involved, according to researchers at the
National Institute of Allergy and Infectious Diseases. One is the production
of an antibody called immunoglobulin E (IgE) that circulates in the blood. The
other part is a type of cell called a mast cell. Mast cells occur in all body
tissues but especially in areas that are typical sites of allergic reactions,
including the nose, throat, lungs, skin, and gastrointestinal tract.
People usually inherit the ability to form IgE against food. Those more likely
to develop food allergies come from families in which allergies such as hay
fever, asthma, or eczema are common.
A predisposed person must first be exposed to a specific food before IgE is
formed. As this food is digested for the first time, tiny protein fragments
prompt certain cells to produce specific IgE against that food. The IgE then
attaches to the surface of mast cells. The next time the particular food is
eaten, the protein interacts with the specific IgE on the mast cells and triggers
the release of chemicals such as histamine that produce the symptoms of an allergic
If the mast cells release chemicals in the nose and throat, the allergic person
may experience an itching tongue or mouth and may have trouble breathing or
swallowing. If mast cells in the gastrointestinal tract are involved, the person
may have diarrhea or abdominal pain. Skin mast cells can produce hives or intense
The food protein fragments responsible for an allergic reaction are not broken
down by cooking or by stomach acids or enzymes that digest food. These proteins
can cross the gastrointestinal lining, travel through the bloodstream and cause
allergic reactions throughout the body.
The timing and location of an allergic reaction to food is affected by digestion.
For example, an allergic person may first experience a severe itching of the
tongue or "tingling lips." Vomiting, cramps or diarrhea may follow.
Later, as allergens enter the bloodstream and travel throughout the body, they
can cause a drop in blood pressure, hives or eczema, or asthma when they reach
the lungs. The onset of these symptoms may vary from a few minutes to an hour
or two after the food is eaten.
Most Likely Suspects
Food allergy patterns in adults differ somewhat from those in children. The
most common foods to cause allergies in adults are shrimp, lobster, crab, and
other shellfish; peanuts (one of the chief foods responsible for severe anaphylaxis);
walnuts and other tree nuts; fish; and eggs.
In children, eggs, milk, peanuts, soy and wheat are the main culprits. Children
typically outgrow their allergies to milk, egg, soy and wheat, while allergies
to peanuts, tree nuts, fish and shrimp usually are not outgrown.
Adults usually do not lose their allergies.
A Growing Problem
"The prevalence of food allergy is growing and probably will continue
to grow along with all allergic diseases," says Robert A. Wood, M.D., director
of the pediatric allergy clinic at Johns Hopkins Medical Institutions in Baltimore.
Wood says that research over the last three decades indicates that the number
of people with allergies is skyrocketing in developed and developing countries,
but not in underdeveloped areas.
"The fewer germs in terms of infection and the environment, the more time
the immune system has to worry about things like allergens," says Wood.
"Recent studies indicate that growing up in a large family or daycare center
actually decreases the likelihood of developing an allergy."
Wood, who has had a severe peanut allergy since he was a toddler, says allergic
reactions to foods can vary dramatically. "They can range from just a mild
rash to very severe swelling in the throat and the airways in the lungs so that
there is a complete inability to breathe," he says.
Wood's parents learned of their son's allergy when they introduced him to peanut
butter. "The first time I had peanut butter I developed a rash and severe
swelling in my face," he says. "I'm extremely allergic. Just being
around when a peanut shell is broken and dust is being released is enough to
cause a reaction.
"I've had a number of very dangerous reactions," Wood says. "People
with a food allergy typically walk around with a little bit of fear all the
time. Once it starts, it's a fear-generating experience."
When Sarah Buster of Columbia, Md., was 4 months old, her parents discovered
that an allergy to milk was causing her eczema, a chronic skin inflammation.
Her skin improved with a switch to a soy-based formula. Sarah's doctor believed
there was little cause for concern since many infants have eczema and most outgrow
it by age 2. Sarah didn't. Tests later indicated that she was allergic to eggs,
peanuts, tree nuts, penicillin, tree pollen, ragweed, dust mites, and dogs and
It was then that Sarah's parents, Mike and Brenda Buster, began reading food
labels as carefully as they would a legal contract. They joined a food allergy
advocacy group, replaced the carpet in Sarah's bedroom and throughout the house
with hardwood floors, placed dust mite covers over her bedding, gave away the
family's dogs, and kept Sarah indoors as much as possible.
A small wooden chair with a wicker seat has taken the place of upholstered
furniture for Sarah, and devices that filter dust, pollen and other particles
hum both upstairs and downstairs.
For a time, soaking baths and ointment head-to-toe helped keep her skin moist,
and a prescription antihistamine eased the itching enough so she could sleep.
However, Sarah's eczema soon worsened again.
"Sarah's itching would be so severe that we could stand right by her and
call her name and she would not respond because she was so focused on scratching,"
says Brenda Buster. "She would scratch until she bled because the pain
felt better than the itch."
Finally, allergists at Johns Hopkins eliminated all conventional food and put
her on a special formula made of amino acids. Sarah also started a four-month
regime of prednisone, a drug that mimics the effects of the body's natural corticosteroid
hormones and suppresses the activity of the immune system.
Eventually, her diet was expanded to six foods that doctors believed she was
not allergic to: turkey, pork, rice, apples, grapes and tomatoes, supplemented
by the special formula.
Sarah's skin cleared and after several months she began a series of dietary
"challenges"--tests to determine whether specific foods cause an allergic
reaction. Several years later, Sarah eats a more varied diet, and the Busters
maintain a list of safe foods and those that cause an allergic reaction.
"The most difficult thing I have faced with my allergies is that when
I see my friends eating something that I know I can't have, it just makes me
feel left out," says Sarah.
"We never order food for Sarah at a restaurant because, even if the ingredients
in the food itself are safe, there is a considerable chance for cross-contamination
with something that's unsafe for her to eat," says Mike Buster. "For
example, a baked potato might be safe, but if the person preparing the potato
even touched a dairy, nut or egg product and then touched the potato, Sarah
could have a serious reaction.
"We go out to eat, but we bring all her food with us," he says. "It's
just not worth taking the chance."
Wood, who cares for Sarah at Johns Hopkins, says, "She's got it a lot
tougher than someone who just has a peanut allergy. She's dealing with this
stuff on an every-single-meal basis. Her parents have really helped provide
her with a wonderful life."
That life includes her favorite activities--ice-skating (she likes the cool
air of the rink) and swimming (the moisture and chlorine are beneficial to her
skin, according to her doctors).
Sarah continues to outgrow some of her allergies, and has added about a dozen
foods into her diet over the past year, Wood says.
"The taste in my mouth when I'm trying something new is very different,"
says Sarah. "Strawberries felt hard because of the seeds. They tasted great
but I didn't like the texture, so my dad tried to take the seeds out. I still
didn't like the strawberries that much, but I kept reminding myself over and
over again that if I passed the test, I would be able to have a lot of things
with strawberries in it. Like now I can have strawberry Skittles."
The food at Sarah's Montessori school is nut-free, and on special school occasions,
Brenda Buster tries to prepare something that Sarah and her classmates can enjoy,
such as some types of candy, homemade cupcakes made without eggs or dairy products,
a nondairy frozen dessert, or popcorn prepared at home.
"We make our own bread and most other foods," says Brenda. "Although
we do have several more products we can buy, including one brand of potato chips
and one brand of pretzels, saltines and several types of canned vegetables."
Still, the Busters must be vigilant and can be found constantly checking labels.
For example, a type of food may be safe from one manufacturer but not from another.
"One brand of candy corn may be OK, while another contains eggs,"
Even foods that have proved to be safe previously can subsequently cause a
problem. "Manufacturers can change the ingredients without changing the
packaging," adds Mike Buster. "We appreciate manufacturers who clearly
label their products."
Food Labeling: A Critical Component
Currently, the only way to treat food allergies is to avoid the foods that
trigger reactions. Even the most diligent label-readers and ingredient-checkers
likely will be inadvertently exposed to proteins that elicit an allergic response
at some point. That's why Wood, Sarah and others with food allergies severe
enough to cause anaphylactic reactions should wear medical alert bracelets or
necklaces and carry a syringe of adrenaline (epinephrine) obtained by prescription
from their physicians.
Anaphylactic allergic reactions can be fatal even when they begin with mild
symptoms such as a tingling in the mouth and throat or gastrointestinal discomfort.
Antihistamines and bronchodilators can be used to treat less severe symptoms.
Since 2000, the FDA has presented information on allergen risk and labeling
requirements at more than a dozen locations nationwide, says Kenneth J. Falci,
Ph.D., who leads the FDA's initiatives on food allergies.
The meetings provide the FDA with firsthand accounts from people with food
allergies and data that can be used to improve consumer labeling.
The FDA's food allergy efforts include focusing on the eight most common food
allergens: milk, eggs, fish, wheat, tree nuts, peanuts, soybeans and crustaceans
(such as shrimp and crabs). Proteins in these eight major foods are estimated
to cause 90 percent of the allergic reactions in the United States.
Food manufacturers and consumer groups are working with the FDA to increase
public awareness of the seriousness of food allergen reactions and to ensure
that allergens are appropriately labeled in food products.
An allergen labeling program and a "code of practice" developed by
the National Food Processors Association that calls for listing the eight most
common food allergens in "plain language" are among the voluntary
efforts being undertaken.
An example of "plain language" is using the word "milk"
in a product's ingredient list as well as the less familiar "caseinate"
or using "eggs" in addition to "albumin."
Falci says FDA investigators nationwide are being trained how to properly inspect
food-processing plants for allergen control procedures. In addition, FDA officials
have updated a 1996 notice to the food industry addressing the problem of undeclared
allergens in food by recently publishing a
compliance policy guide.
Falci regularly speaks to food industry gatherings across the country to discuss
many allergen topics, including methods being used by some processors to avoid
problems related to food allergies.
"Sharing 'best practices' in the industry through workshops is a really
good way to get people to talk to each other," Falci says. "This is
not a competitive edge issue. This is a safety concept, and sharing these thoughts
is helpful to everyone in the industry.
"Altering production scheduling is a practice that can have a huge impact
on minimizing the inadvertent introduction of undeclared allergens," says
Falci. "Manufacturers who use shared equipment to process foods without
allergens can benefit from following a carefully laid out production plan, such
as running non-allergen-containing products first, followed by those containing
allergens, then a clean-up step."
The payoff? The shared equipment is less likely to contaminate other products
with undeclared allergens.
The FDA is meeting with the food industry, consumers, trade associations and
consumer advocate groups to discuss ways to improve the identification of food
allergens within the ingredients list.
Falci says that labeling food allergens in plain language--a source statement
simple enough for a child to know if an ingredient is derived from soy or milk,
for example--and precautionary food labeling are among the subjects discussed.
The Federal Food, Drug, and Cosmetic Act requires, in virtually all cases,
that all the ingredients of a food be listed on the food label. Two exemptions
to the labeling requirements recently have been involved in a number of reported
food allergen reactions: the collective naming of spices, flavorings, and colorings;
and insignificant levels of additives in a food that do not have a technical
or functional effect on the final product. The FDA, however, does not consider
food allergens eligible for the latter labeling exemption. The agency also strongly
encourages the declaration of an allergenic ingredient in a spice, flavor, or
"While the FDA believes that food processors make a sincere effort to
label the ingredients in their food products completely, it's clear from data
on food recalls that firms do miss including some allergenic ingredients on
their food labels," says Falci.
Gaps in Allergen Labeling
Between September 1999 and March 2000, FDA researchers working with state inspectors
from Wisconsin and Minnesota inspected 85 bakery product, ice cream and candy
manufacturers for allergen labeling and cross-contamination issues, with a focus
on peanut and egg allergens. Many of the firms in the study were small- to medium-sized
operations. The joint study was prompted, in part, by a jump in the number of
national recalls due to allergy-related ingredients not being listed on labels.
Samples were collected for egg and peanut protein analysis only when labeling
or cross-contamination issues were identified by the investigator. Eighteen
of the 73 samples (25 percent) of ice cream, bakery and candy food products
tested positive for peanut allergens, although peanuts were not listed on product
labels. Investigators also found that companies unintentionally introduced food
allergens into other foods through poor cleaning and cooking schedules or improper
cleaning of utensils.
"These findings show that more work is needed," Falci says.
The inspectors also found that just over half of the manufacturers checked
their products to ensure that the labels accurately reflected all of the ingredients.
"We certainly have legal authority at the moment to allow for recalls
of undeclared allergens, and recalls are occurring for that reason," Falci
says. "We're only in the beginning stages of negotiating and talking with
the food industry about some things we'd like to potentially see on the label.
However, the industry is beginning to take voluntary actions, which we applaud."
The Food Allergy & Anaphylaxis Network (FAAN), based in Fairfax, Va., has
been an advocate for simple, clear and accurate food labels for a decade. "Reading
food labels is the only way that food-allergic consumers can avoid dangerous
allergens in packaged food," says Anne Muñoz-Furlong, FAAN founder
and president. "If food manufacturers don't follow good manufacturing practices
and carefully control that what is in the package matches what is on the label,
we are all in big trouble."
According to Muñoz-Furlong, many large food companies have long been
aware of how serious food allergies can be, and have made appropriate changes
in their manufacturing and labeling practices. There are still many more companies
that have yet to take the issue seriously.
For example, Muñoz-Furlong says that today there are more than a dozen
ways to indicate the presence of milk protein without using the word "milk."
Another common problem is the term "nondairy." Many consumers mistakenly
believe that nondairy means there is no milk in a product. Current labeling
guidelines allow the use of "nondairy" when the foods contain milk
In addition, manufacturers may use the term "natural flavors" even
when the product contains major allergens. To avoid a major allergen, a food-allergic
consumer would need to call the manufacturer before purchasing the product to
confirm that an allergen was present.
Common Symptoms of an Allergic Reaction to Food
Symptoms typically appear within minutes to two hours after a person has
eaten the food to which he or she is allergic.