Food Allergies: When Food Becomes the Enemy
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, that's reality.
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 allergy expert.
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 reaction.
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
"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
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
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
"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
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
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," says Brenda.
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
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 color.
"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
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
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 byproducts.
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
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.
- Tingling sensation in the mouth
- Swelling of the tongue and throat
- Difficulty breathing
- Abdominal cramps
- Drop in blood pressure
- Loss of consciousness, and death.