#### U. S. Food and Drug AdministrationFDA ConsumerMay 1994

FOOD ALLERGIES                 RARE BUT RISKY
Do you start itching whenever you eat peanuts? Does seafood causeyour stomach to churn?  Symptoms like these cause millions ofAmericans to suspect they have a food allergy.
But true food allergies affect a relatively small percentage ofpeople:  Experts estimate that only 2 percent of adults, and from2 to 8 percent of children, are truly allergic to certain foods.Food allergy is different from food intolerance, and the term issometimes used in a vague, all-encompassing way, muddying thewaters for people who want to understand what a real food allergy is.
"Many people who have a complaint, an illness, or some discomfortattribute it to something they have eaten.  Because in thiscountry we eat almost all the time, people tend to draw falseassociations between food and illness," says Dean Metcalfe,M.D., head of the Mast Cell and Physiology Section at theNational Institute of Allergy and Infectious Diseases.
ALLERGY AND INTOLERANCE--DIFFERENT PROBLEMS
The difference between an allergy and an intolerance is how thebody handles the offending food.  In a true food allergy, thebody's immune system recognizes a reaction-provoking substance,or allergen, in the food--usually a protein--as foreign andproduces antibodies to halt the "invasion."  As the battle rages,symptoms appear throughout the body.  The most common sites arethe mouth (swelling of the lips), digestive tract (stomachcramps, vomiting, diarrhea), skin (hives, rashes or eczema), andthe airways (wheezing or breathing problems).  People withallergies must avoid the offending foods altogether.

Cow's milk, eggs, wheat, and soy are the most common sources offood allergies in children.  Allergists believe that infantallergies are the result of immunologic immaturity and, to someextent, intestinal immaturity.  Children sometimes outgrow theallergies they had as infants, but an early peanut allergy may belifelong.  Adults are usually most affected bytree nuts, fish, shellfish, and peanuts.
Food intolerance is a much more common problem than allergy.Here, the problem is not with the body's immune system, but,rather, with its metabolism.  The body cannot adequately digest aportion of the offending food, usually because of some chemicaldeficiency.  For example, persons who have difficulty digestingmilk (lactose intolerance) often are deficient in the intestinalenzyme lactase, which is needed to digest milk sugar (lactose).The deficiency can cause cramps and diarrhea if milk is consumed.Estimates are that about 80 percent of African-Americans havelactose intolerance, as do many people of Mediterranean orHispanic origin.  It is quite different from the true allergicreaction some have to the proteins in milk.  Unlike allergies,intolerances generally intensify with age.
DANGEROUS DISHES
For people with true food allergies, the simple pleasure ofeating can turn into an uncomfortable--and sometimes evendangerous--situation.  For some, food allergies cause only hivesor an upset stomach; for others, one bite of the wrong food canlead to serious illness or even death.
Food intolerance may produce symptoms similar to food allergies,such as abdominal cramping.  But while people with true foodallergies must avoidoffending foods altogether, people with food intolerance canoften eat some of the offending food without suffering symptoms.The amount that may be eaten before symptoms appear is usuallyvery small and varies with each individual.
WHEN FOOD ADDITIVES ARE A PROBLEM
Over the years, people have reported to FDA adverse reactions tocertain food additives, including aspartame (a sweetener),monosodium glutamate (a flavor enhancer), sulfur-basedpreservatives, and tartrazine, also known as FD&C; Yellow No. 5 (afood color).  The federal Food, Drug, and Cosmetic Act requiresthat FDA ensure the safety of all substances added to foods, butindividual health conditions sometimes cause problems withcertain additives.
Aspartame
After reviewing scientific studies, FDA determined in 1981 thataspartame was safe for use in foods.  In 1987, the GeneralAccounting Office investigated the process surrounding FDA'sapproval of aspartame and confirmed the agency had actedproperly.  However, FDA has continued to review complaintsalleging adverse reactions to products containing aspartame.  Todate, FDA has not determined any consistent pattern of symptomsthat can be attributed to the use of aspartame, nor is the agencyaware of any recent studies that clearly show safety problems.
Carefully controlled clinical studies show that aspartame is notan allergen.  However, certain people with the genetic diseasephenylketonuria (PKU), those with advanced liver disease, andpregnant women with hyperphenylalanine (high levels ofphenylalanine in blood) have a problem with aspartame becausethey do not effectively metabolize the amino acid phenylalanine,one of aspartame's components.  High levels of this amino acid inbody fluids can cause brain damage.  Therefore, FDA has ruledthat all products containing aspartame must include a warning tophenylketonurics that the sweetener contains phenylalanine.
Monosodium glutamate
Monosodium glutamate (MSG) has been used for many years in homeand restaurant foods, and in processed foods.  People sensitiveto MSG may have mild and transitory reactions when they eat foodsthat contain large amounts of MSG (such as would be found inheavily flavor-enhanced foods).  Because MSG is commonly used inChinese cuisine, these reactions were initially referred to as"Chinese restaurant syndrome."
FDA believes that MSG is a safe food ingredient for the generalpopulation.  It is regarded by the agency as among foodingredients that are "generally recognized as safe."  FDA hasstudied adverse reaction reports and other data concerning MSG'ssafety.  The agency also has an ongoing contract with theFederation of American Societies for Experimental Biology to re-examine the scientific data on possible adverse reactions toglutamate in general.  MSG must be declared on the label of anyfood to which it is added.
Sulfites
Of all the food additives for which FDA has received adversereaction reports, the ones that most closely resemble trueallergens are sulfur-based preservatives.  Sulfites are usedprimarily as antioxidants to prevent or reduce discoloration oflight-colored fruits and vegetables, such as dried apples andpotatoes, and to inhibit the growth of microorganisms infermented foods such as wine.
Though most people don't have a problem with sulfites, they are ahazard of unpredictable severity to people, particularlyasthmatics, who are sensitive to these substances.  FDA uses theterm "allergic-type responses" to describe the range of symptomssuffered by these individuals after eating sulfite-treated foods.Responses range from mild to life-threatening.
FDA's sulfite specialists say scientists, at this time, are notsure how the body reacts to sulfites.  To help sulfite-sensitivepeople avoid problems, FDA requires the presence of sulfites inprocessed foods to be declared on the label, and prohibits theuse of sulfites on fresh produce intended to be sold or servedraw to consumers (see "A Fresh Look at Food Preservative" in theOctober 1993 FDA Consumer).
FD&C; Yellow No. 5
Color additives must go through the same safety approval processas food additives.  But one color, FD&C; Yellow No. 5 (listed astartrazine on medicine labels), may prompt itching or hives in asmall number of people.
Since 1980 (for drugs taken orally) and 1981 (for foods), FDA hasrequired all products containing Yellow No. 5 to list it on thelabels so sensitive consumers could avoid it.  (As of May 8,1993, food labels must list all certified colors as part of therequirements of the Nutrition Labeling and Education Act of 1990.See "From Shampoo to Cereal, Seeing to the Safety of ColorAdditives" in the December 1993 FDA Consumer.)

TRUE ALLERGIES
Heredity may cause a predisposition to have allergies of anytype, and repeated exposure to allergens starts sensitizing thosewho are susceptible.  Some experts believe that, rarely, aspecific allergy can be passed on from parent to child.  Severalstudies have indicated that exclusive breast-feeding, especiallywith maternal avoidance of major food allergens, may deter somefood allergies in infants and young children.  (Smoking duringpregnancy can also result in the increased possibility that thebaby will have allergies.)  Most patients who have true foodallergies have other types of allergies, such as dust or pollen,and children with both food allergies and asthma are at increasedrisk for more severe reactions.
LIFE-THREATENING REACTIONS
The greatest danger in food allergy comes from anaphylaxis, aviolent allergic reaction involving a number of parts of the bodysimultaneously.  Like less serious allergic reactions,anaphylaxis usually occurs after a person is exposed to anallergen to which he or she was sensitized by previous exposure(that is, it does not usually occur the first time a person eatsa particular food).  Although any food can trigger anaphylaxis(also known as anaphylactic shock), peanuts, tree nuts,shellfish, milk, eggs, and fish are the most common culprits.  Aslittle as one-fifth to one-five-thousandth of a teaspoon of theoffending food has caused death.
Anaphylaxis can produce severe symptoms in as little as 5 to 15minutes, although life-threatening reactions may progress overhours.  Signs of such a reaction include:  difficulty breathing,feeling of impending doom, swelling of the mouth and throat, adrop in blood pressure, and loss of consciousness.  The soonerthat anaphylaxis is treated, the greater the person's chance ofsurviving.  The person should be taken to a hospital emergencyroom, even if symptoms seem to subside on their own.
There is no specific test to predict the likelihood ofanaphylaxis, although allergy testing may help determine what aperson may be allergic to and provide some guidance as to theseverity of the allergy.  Experts advise people who aresusceptible to anaphylaxis to carry medication, such asinjectable epinephrine, with them at all times, and to check themedicine's expiration date regularly.  Doctors can instructpatients with allergies on how to self-administer epinephrine.Such prompt treatment can be crucial to survival.
Injectable epinephrine is a synthetic version of a naturallyoccurring hormone also known as adrenaline.  For treatment of ananaphylactic reaction, it is injected directly into a thighmuscle or vein.  It works directly on the cardiovascular andrespiratory systems, causing rapid constriction of blood vessels,reversing throat swelling, relaxing lung muscles to improvebreathing, and stimulating the heartbeat.
Epinephrine designed for emergency home use comes in two forms:a traditional needle and syringe kit known as Ana-Kit, or anautomatic injector system known as Epi-Pen.  Epi-Pen's automaticinjector design, originally developed for use by militarypersonnel to deliver antidotes for nerve gas, is described bysome as "a fat pen."  The patient removes the safety cap andpushes the automatic injector tip against the outer thigh untilthe unit activates.  The patient holds the "pen" in place forseveral seconds, then throws it away.
While Epi-Pen delivers one premeasured dosage, the Ana-Kitprovides two doses.  Which system a patient uses is a decision tobe made by the doctor and patient, taking into account thedoctor's assessment of the patient's individual needs.
ADVICE FROM STUDY
Hugh A. Sampson, M.D., and colleagues at Johns Hopkins UniversitySchool of Medicine in Baltimore, MD., published a study ofanaphylactic reactions in children in the Aug. 6, 1992, issue ofthe New England Journal of Medicine.  The study involved 13children who had severe allergic reactions to food:  Six died,and seven nearly died.  Among the study's conclusions:
- Asthma, a disease with allergic underpinnings, was common toall children in the study. Epinephrine should be prescribed and kept available for thosewith severe food allergies.
Children who have an allergic reaction should be observed forthree to four hours after a reaction in a medical center capable ofdealing with anaphylaxis.
Anne Munoz-Furlong, who founded The Food Allergy Network forpeople with food allergies in 1991 after struggling to deal withher own child's allergies, comments:  "My youngest daughter wasdiagnosed with milk and egg allergies when she was 9 months old,nine years ago.  We tried to lead a life around her restricteddiet.  For example, we had Jell-O mold for her first birthdaybecause I didn't know it was possible to create a cake withoutmilk or eggs.  I knew there must be other families strugglingwith the same issue."
FINDING THE FORBIDDEN
Because there is no "cure" for food allergies other than strictavoidance of an offending food, one of the biggest problems thosewith food allergies face is verifying whether a forbiddenproduct is contained in a particular food. For example, inSampson's study, all six deaths occurred because either the childor the parent was unaware the food contained a substance to whichthe child was allergic.  Munoz-Furlong says the NutritionLabeling and Education Act, which requires more complete foodlabeling, should greatly help people with food allergies to avoiddangerous foods.
"The new labeling changes will make it easier for the consumer toreadily identify things they could be allergic to," says LindaTollefson, D.V.M., chief of the epidemiology branch at FDA'sCenter for Food Safety and Applied Nutrition.  "Before this lawwas passed, true allergens were required to be on the label, butthe exceptions were standardized foods, which will now have tolist all ingredients."
According to Elizabeth J. Campbell, director of the center'sdivision of programs and enforcement policy, the principleunderlying standardized foods originally was that peoplebasically knew what was in various foods.
"Originally, food standards were adopted to ensure uniformity.  Ifyou saw a product labeled mayonnaise, food standardization meantit had to be mayonnaise.  People used to know what was inmayonnaise; nowadays they have to be told that mayonnaisecontains both eggs and oil," Campbell says. "Years ago, when thelaw was first written to provide for standards of identity forcertain foods, it only required that optional ingredients bedeclared.  The new law stipulates that all ingredients instandardized foods must be declared."  (See "Ingredient labeling:What's in a Food?" in the April 1993 FDA Consumer.)
Campbell believes that once the labeling is in place, consumerswill have the information they need to make correct food choices."In most cases, ingredients have to be labeled simply becausethey are ingredients, not because they are unsafe," she stresses."For those with food allergies, I think it is more of a patienteducation problem."
Food additives, such as sulfites and certain colors, can alsocause problems for people sensitive to them.  (See "A Fresh Lookat Food Preservatives" in the October 1993 FDA Consumer and "FromShampoo to Cereal:  Seeing to the Safety of Color Additives" inthe December 1993 FDA Consumer.)
"If you have a food allergy, you really have to alter your life,"Tollefson says.  "You have to really read labels, and really becareful about what you eat."
Steve Taylor, Ph.D., a professor and head of Department of FoodScience and Technology at the University of Nebraska in Lincoln,says the biggest problem for people with food allergies isrestaurant food.  Historically, restaurants have been regulatedby local heath departments and have not had to label foods.
"For many restaurants, labeling of food products they serve wouldcause horrendous problems...what about chalkboard menus?  Howwould you include all the ingredients?  Enforcement would be anightmare," he admits.
But steps are being taken to better educate restaurant employees.The Food Allergy Network and The American Academy of Allergy andImmunology, along with the National Restaurant Association,recently produced a pamphlet on food allergies, which has beendistributed to 30,000 members of the association.  The brochureexplains what restaurants can do to help customers who need toavoid certain foods, defines anaphylaxis, and advises employeeson what to do if food allergy incidents occur.
John A. Anderson, M.D., director of the Allergy and ImmunologyTraining Program at Henry Ford Hospital in Detroit, says changesin food habits may be responsible for the feeling some physicianshave that food allergies may be on the rise.
"You could make a case for the fact that we are introducingpeanuts, in the form of peanut butter, to people at a very youngage, which would affect the prevalence rate for people who aresensitive to that allergen," he notes.  "In Japan, where they usemore soy, there is a higher prevalence of soy allergy.  Myfeeling is that as soy, a cheap protein supplement, is put in alot of commercial foods you will see an increase in the ratesensitivity worldwide."
Metcalfe say that if food allergies are rising, it is due to morecommon use of foods that tend to be allergenic.  He cites milk asa source of protein supplement in many prepared foods, and pointsout that people are eating more exotic seafood and more fish.
"But it's important to remember that the majority of people withtrue food allergies are allergic to three or fewer foods,"Metcalfe says.
Other than advising anyone with a known or suspected severe foodallergy to carry and know how to self-administer epinephrine,there is no treatment for food allergy other than to eliminatethe offending food.  But Metcalfe is optimistic about the future.
"I don't think it is likely a drug will be found to prevent foodallergies.  But I do think within 10 years we will see allergyshots available for some of the more common food allergies,because we are learning to identify and purify food allergens.  Ithink we will see some development of immunotherapy for foodallergies," he says.
FOOD ALLERGIES AND BIOTECHNOLOGY
People with food allergies have expressed the concern that newvarieties of food, developed through the new techniques ofbiotechnology(such as gene splicing), may introduce allergensnot found in the food before it was altered.
FDA addressed this concern in its 1992 biotechnology policystatement and said it will regulate whole foods developed throughbiotechnology by applying the same rigorous safety standards asfor all other foods.  The agency is taking steps to ensure thatfoods developed though biotechnology do not pose any new risksfor consumers.
Under the new policy guidelines, a protein copied by geneticengineering from a food commonly known to cause an allergicreaction is presumed to be allergenic unless clearly provenotherwise.  Any food product of biotechnology that contains suchproteins must list the allergen on the label.
Labeling would not be required if the manufacturer coulddemonstrate that the allergen was not transferred.  For example,if a food company were to breed potatoes containing a geneticallyengineered soy protein (to which some people might be allergic),the labeling on the potatoes would have to disclose the presenceof the soy protein.  But labeling would not be required ifscientific data clearly showed that the protein had been changedand no longer contained the soy allergen.
To ensure that FDA has state-to-the-art information for its foodbiotechnology policy, the agency will sponsor a scientificconference in the spring of 1994 to discuss what makes asubstance a food allergen.
HOW TO COPE
What should you do if you suspect you have a food allergy?
The Food Allergy Network's Anne Munoz-Furlong suggests keeping afood diary as a first step, writing down everything you eat ordrink for a one- or two-week period.  Note any symptoms and howlong it took for such symptoms to develop.
But Furlong and other experts agree that those who suspect foodallergies also need to be evaluated by a physician with intensivespecialty training in allergy and immunology.  Be sure to discusswhat diagnostic and treatment plan is anticipated, and the costs.
Ask if the tests have been proven effective by accepted standardsof scientific evaluation.
"Go to a board-certified physician who is an allergy expert,"advises Paul C. Turkeltaub, M.D., associate director of thedivision of allergenic products and parasitology at FDA's Centerfor Biologics Evaluation and Research.  "Be very wary of claimsof food allergy to explain chronic, common complaints."
The diagnosis of food allergy requires a careful history,physical exam, appropriate exclusion diet, and diagnostic test torule out other conditions.  Tests can include direct allergyskin tests, blood tests, or "elimination and challenge" tests forsuspected foods.
The most accurate kind of test is a controlled challenge test,often done in "blind" or "double-blind" fashion to eliminatepsychological factors.  In a blind challenge, the patient isgiven either a sample of the food, without being told what it is,or a placebo, an inert substance used as a control in the test.The observer (a doctor or assistant), however, knows what thesubstance is.  Both patient and observer record any symptoms ofallergic reaction.  In a double-blind challenge, neither thepatient nor the observer knows if the patient is given the food(allergen) or the placebo.
In recent years, unproven tests such as "food cytotoxic bloodtests" and "sublingual provocation food testing" have been promotedas supposed "diagnostic" tools to detect food allergies.  FDAbelieves that food cytotoxic blood tests are not supported bywell-controlled studies and clinical trials.
In food cytotoxic testing, a test tube of blood is taken from thepatient.  The white cells (leukocytes) are mixed with plasma andsterile water and placed on microscope slides coated with driedextracts of a particular food.  The reaction of the cells is thenexamined under a microscope; if they change shape, disintegrate,or collapse--or the person examining them says they do--the patientis supposedly allergic to that particular food.  Test results maybe interpreted by a "nutritional counselor" working oncommission, who recommends vitamins and minerals (often availableon site) that the patient needs to correct his or her "allergiccondition."  But FDA and other experts emphasize there is noevidence that such tests are valid in diagnosing food allergies.
Sublingual provocation food testing dates back to 1944.  The testconsists of placing three drops of an allergenic extract under apatient's tongue and waiting 10 minutes for any symptoms toappear.  When the doctor is satisfied he has determined the causeof the symptoms, he administers a "neutralizing" dose, which isusually three drops of a diluted solution of the same allergenicextract.  The symptoms are then expected to disappear in the samesequence in which they appeared.  Advocates claim that if theneutralizing dose is given before a challenge test (for instance,eating a meal containing the offending food), the person will nothave symptoms.
But after careful study of existing data, The American Academy ofAllergy and Immunology says no controlled clinical studiesdemonstrate either diagnostic or therapeutic effects ofsublingual provocation food testing.  The academy concludes thatuse of the tests should be reserved for experiments inwell-designed trials.
If you are diagnosed with a food allergy, scrutinize food labelsto detect potential sources food allergens.  When eating out, askabout ingredients if you are unsure about a particular food; askto talk to the manager of the restaurant about ingredients inspecific dishes.
Keep epinephrine with you and know how to administer it.  If youdo experience a reaction, seek medical attention immediately,even if the symptoms are mild or seem to subside.  Mild symptomsmay be followed 10 to 60 minutes later by the onset of severeproblems.
MORE INFORMATION
For more information about food allergies, contact the followinggroups:
The Food Allergy Network10400 Eaton Place Suite 107Fairfax, VA  22030(703) 691-3179(1-800) 929-4040
American Academy ofAllergy, Asthma and Immunology611 East Wells St.Milwaukee, WI 53202(414) 272-6071
Physician Referral Hotline(1-800) 822-ASMA
The American Dietetic Association216 W. Jackson Blvd.Chicago, IL 60606-6995(1-800) 877-1600
For a free copy ofAnFDA Consumer Special Report: Focus on Food Labeling,which includes the article on ingredient labeling,write to FDA, HFE-88, 5600 Fishers Lane, Rockville, MD 20857.
Department of Health and Human ServicesFood and Drug AdministrationPublication No. (FDA) 94-2279
*Note: Addresses and phones were updated June 1997*

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