Journal of Scientific & Industrial Research

Vol. 62, August 2003 , pp 755-765

Food Allergy - How Much of a Problem Really is This in India?

S V Ganga! and B K Malik*

Center of Biochemical Technology (CS IR) , Mall Road . Delhi I I 0 007

Food allergy is est imated to affect 1-2 per cent of the whole population , however its prevalence in chil dren is quite high. Food hypersensitivity is an immunological reaction resulting from the ingestion of a food. Thi s reaction occu rs only in some patients when only a minute quantity of the substance is ingested. The reaction cou ld be mild , moderate or severe leading to anaphylaxis and sudden death. lgE mediated reactions account for most of the well-characterized food allergic reactions although non-lgE mediated immune response is also seen occasionall y. Although there has been a great concern in western countries about food allergies, in India the prevalence of food allergy although preserved has not been systematically studied. Unfortunately there is not much awareness about food hypersensitivity reaction in Indi a. Indi an food is quite complex and it is necessary for a high risk person to know what kind of food he is allergic to. Diagnosis of food allergy is quite lengthy procedure and many times it is not possible to avoid the offending food. There has been a great concern in many counlries including Indi a about the adverse reaction to foods. However because of Jack of data in food allergy in Indi a it is quite difficult to evaluate the allergenicty of GM food.

Keywords: Food allergy, Allergy, Food packaging industry

Currently the food safety tssue has gained much importance due to growth of food processing and readymade food packaging industries. In addition to toxic effects of certain foods, many produce adverse reaction in some individuals. Adverse food reactions can be defined as abnormal responses to an ingested food. The abnormal food reaction could be either due to food hypersensitivity, (food allergy) or food intolerance.

During the last decade food allergies have attracted considerable attention from the industry and government regu latory authorities. Recently Indian government has planned to boost food packagi ng industry, therefore, it is a ll the more relevant to know about foods causing allergic reactions.

Food allergy is an immunological reaction suffered by some individuals resulting from the consumption of certain foods and it involves IgE antibody, responsible for a wide range of anaphylactic reactions. Foods that induce excessive IgE synthesis are called allergens. The specific IgE antibodies are produced by some atopic individual s against certain allergens in food which bind to mast

* Corresponding author email: bkmalik@cbt.res.in

cells or basophil s. A second exposure of such allergens results in binding of the a lle rgen with the IgE on these cells leading to their degranulation and release of certain mediators which cause various allergic reactions such as, di arrhoea, asthma, rhiniti s, urticaria, and eczema, or. even severe systemic reactions leading to death . Food intolerance is described as an abnormal physiologic response to some ingested food s and is not immunologic but mainly caused by anaphylactoid react ions, metabolic disorders and idiosyncratic responses, They are not typically caused by food protei ns but by many other molecules.

The IgE mediated hypersens iti vity to food s causing allergic reactions such as as thma, rhiniti s, atopic dermatiti s, urticaria, oral symptoms such as swelling of lips and tongue, gastrointestinal di sturbances or even anaphyl ax is of vary ing degree are quite common . In this, the tolerance level of food prote ins is extremely low. Although common man perceives allergic reactions after consuming different types of foods to be quite high, very few significant data is publi shed to address thi s issue in Indi a. Internationall y 1-2 per cent of adult population is reported to be affected by true food allergy and its prevalence is higher in children, about 6-8 per cent.

756 J SCI IND RES VOL 62 AUGUST 2003

The risk of suffering an allergic reaction depends onthe degree of sensitivity of an individual to theallergens, the potency of the allergen, and thequantity or dose of the allergen consumed. Theseallergens could be identified and require carefultracking during food manufacture. Since food allergyinvolves abnormal responses to proteins, food allergyis of great concern to biotechnologists developinggenetically modified foods.

The first report of adverse reaction to foodssuch as milk was recorded 2000 y ago byHyppocrates I. In India. the traditional systems ofmedicine describes many foods as causing pitta vatuor cough and are forbidden in some diseaseconditions or in some seasons.

Our understanding of food allergy has madetremendous strides recently. The major advance inour knowledge of food allergy emerged in 1921 whenPranstsitz and Kustner2 demonstrated that a substancein the serum of Kustner was responsible for theallergic reaction to fish and the reaction could betransferred to another individual. It was demonstratedthat injection of small amount of Kustner's serum(who was highly sensitive to fish) into the skin ofPrausnitz (who was not sensitive to fish) forearm, awheal and flare would develop after the ingestion offish by him. Attention towards food allergic reactionsincreased when Youninger et a/ ..1 and Sampson et a/.4

published reports describing deaths associated withfood allergic reactions. In the US, total countrynetworks of patients sensitive to peanut have beenformed and are given full information on preventionof allergies. In western countries governmentregulatory agencies recognized the potential danger ofIgE mediated food allergens and the public, medicalcommunity and media have become quite aware ofpotential anaphylactic allergic reactions in someindividuals arising from inadvertent consumption ofthe specific offending food. In India due to unknownreasons the incidence of food allergy is very smallcompared to that in western countries. The generalpublic is not aware of the importance of foodsensitiveness in triggering allergic manifestationssuch as atopic dermatitis, rhinitis or asthma. Hencefood allergy remains undiagnosed in India. In recentyears, however the incidence of allergic sensitizationis increasing rapidly.

Several studies worldwide have shown thatprevalence of true food allergy particularly in young

••••••:.[(

children is quite significant. The most common foodsidentified as allergic to many people in western worldor consumed world wide are egg, milk, peanuts, andother dry fruits (almonds, pista, chis) soybean.legumes, sea foods, some fruits etc. accounting forover 80 per cent of the food allergies reported. Foodallergies are the single most common cause ofgeneralized anaphylaxis in hospital emergencydepartment accounting for about one third of thecases in western countries. It is established that about100 total cases of food induced fatal anaphylaxisoccur in USA each year. There is a person to personvariation in threshold for the offending foods. But themost sensitive food anergic individuals willexperience reactions from exposure to minutequantities of the offending food).

It is very difficult to identify a particular proteinas allergenic as these proteins do not show anyspecial characteristics on analysis. No particularsecondary or tertiary structure can be described asbeing solely and intrinsically allergenic. No tests suchas, analysis of structure function and physio-chemicalproperties or animal models are available to evaluateor predict allergcnicity of a protein in an objectivemanner. However most of the allergenic proteins haveprotease type of activity. However. some tools areproposed to predict the inherent allergenicity ofproteins. Stability hypothesis states that foodallergens must exhibit sufficient gastric stability toreach the intestinal mucosa for absorption andsensitization to occur.

In India, food allergy is yet not recognized as amajor problem since food allergies are considered asmore easily avoidable. Medical community is awareto some extent about the complaints or patients givinghistory of adverse reaction to pulses such as, blackgram, Cajon pea, french bean, horse gram, lentil,mustered, reddish, some fruits, milk. Howeversystematic reports are not available showingprevalence of food allergies or the important foodallergens in Indian population established by doubleblind placebo controlled food protection tests. Acouple of reports are available describing allergicmanifestation such as pruritis, virticases, angioedema,gastroenteritis, respiratory allergic symptoms onconsumption of certain common foods in allergicpatienrs'', Many foods such as peanut - reported tobe causing major public health problem in the US -has not been of much consequence in India. Very

GANGAL & MALIK: FOOD ALLERGY 757

high degree of sensitivity has been reported in a few patients to gram, urad dal (black gram) etc. Seafood allergy, especially the shrimp allergy has been studied · d ·) 7 X m greater etat s · .

The commonly consumed foods can be class ified as foll ows:

Fruits and vegetables

2 Milk and milk products

3 Eggs and egg products

4 Legumes, peas, peanuts, soybean etc .

5 Cereal s

6 Meat , fish and crustaceans

7 Tree nuts, poppy seeds, sesum seeds and their products

8 Food colours, preservatives, medicines, etc.

The Codex Alimentarius Commiss ion (CAM) has adopted a list of the most common a llergenic foods with IgE mediated reacti ons which include cow's milk, chicken eggs, legumes (such as peanuts, gram beans, green peas), tree nuts (such as a lmonds, cashews, pi stachia, walnut). Sea foods (crustacean and fi sh). Cereal s such as, wheat, barley, ri ce, corn , sorghum. Spices such as turmeric, cumin seeds have been found to be allergenic in Indi an population. In addition some fruits have been reported to cause oral allergy syndrome. However, these are not included in the CAM list.

In practice, very few foods consumed today have been subjec ted to any toxicological studies and yet they are generally accepted to be safe to eat.

Now new procedures are used to preserve foods such as freezing, and irradi ation, which can bring about certain changes in the charac teri stics of foods. More recently biotechnology and genetic engineering have been used to modify common foods expressing improved traits which arc now avail able in the market and possible allergic reacti ons to GM foods are now a major cause of concern. Detecting any potentia l adverse effect to an individual component of a food is extremely difficult. However a person not expecting the presence of any harmful component can run an inherent ri sk, if not aware of foods offending to him, which may be innocuous to others. Hence it is necessary to take up systematic study on common allergic foods in Indian population.

Mechanism of Food Allergy

True food a llergy is an immunological reaction resulting from the ingestion of food or food additive. It can occur in some patients after only a small amount of the substance is ingested . The mucosal barrier of immune system of gastrointestinal tract prevents allergic reactions to foods. Nonimmunologic and immunologic mechani sm operate to block foreign antigens from entering body . The mucosal barrier functi on is reduced if these mechanisms are immature in some infants. Intestinal secretions conta in secretary IgA antibodies . In the gut lumen antigen sp. IgA blocks the absorption of foreign antigens to expose them for proteolytic digesti on. The processing of food antigens by the gut is essential for development of oral tolerance. Exclusive breastfeeding for 6 months has been reported to promote ora l tolerance and prevent food a llergy. Recent studies indicate that initi al sensiti zation ofT-cell s against a llergens takes pl ace in utero by means of transplacenta l transport of a llergens to which the mother is exposed during pregnancy. After birth, during infancy and early childhood, high level exposure to dietary allergens leads to T-cell a llergy . Failure of these allergen dri ven immune deviations during early life seems to be responsible for development of allergic responses to ingested food or other a llergens which continue during adulthood, especially in genetically predi sposed children. While other children a lthough may show an a llergic response to certain foods such as milk or eggs usuall y come out of it within the fi rst I or 2 y. The development of tolerance is a dynamic process and it commences in the childhood and remains acti ve during adulthood. There is substantial evidence that antigen processing by GALT is crucial for tolerance induction. Sometimes food allergy could be due to cross reacti vity of some food allergens to pollen allergens in pollen sensitive patients.

Diagnosis of Food Allergy

Diagnosis of food allergy is a complicated process. While allergic reac tions to food are mostly 1gB-mediated reactions, several immune mechanisms may contribute to adverse reactions to foods that have an immunological bas is. Cross-reactions with pollen allergens and profillin , make the identificati on of true food a llergy di ffi cult. New a lle~gen s may be evolved during process ing or cooking of food. The presence of food spec ifi c IgE in serum or a positive skin prick

758 1 SCI IND RES VOL 62 AUGUST 2003

test does not always correlate with food allergy for many reasons (Table I).

The dignosis of food allergy requires very careful recording of the history of patients' symptoms and food habits, selective skin prick/intradermal test, which could be confirmed by RAST. Skin prick test is often used to diagnose patients with suspected IgE food allergies 9'

10. A positive sk in tes t to a food

indicates the poss ibility that the subject has symptomatic reactivity to that specific food, however, this needs to be confirmed using RAST or DBPCFC 11

• A negative skin test more or less confirms the absence of IgE-mediated allergy to that food. However, in order to get sati sfac tory results with sk in tests the ex tracts need to be fresh and standardized, as some of the allergic components of food are highly labil e. Infants may have IgE-mediated food allergy in the absence of positi ve skin test. The DBPCFC has been considered the standard test for diagnosis of food allergy' 2

•14

• Presentl y, commerciall y available food allergen ex tracts are not standardized and their stability is also not well defined.

The criteria of positive diagnosis by DBPCFI should be assessed by objective ll)1easures such as FEV 1 (forced expiratory volume) and symptom score.

. f I 1s 16 For eczema, sconng systems are o proven va ue · (Table 2).

Most of the pati ents of food a ll ergy present not only skin manifestat ions but also accompanying rhinitis and asthma.

Fruits and Vegetables

The recent recogmt10n that oral allergy syndrome to fresh fruits and vegetables affects some 4 per cent of the subjects suffering from pol lenos is indicates the importance of fruits and vegetables in inducing allergic reactions in adults 10

. Recent data reveal that vegetable food s are the most common causes of food allergies independent of pollenosis in adults, although not much data is available in Indi a on

Table 1- Methods used in diagnosis of food allergy

l11 vivo In vitro

Skin prick test Medical hi story

Doub le blind placebo Diet diary

Contro ll ed food ch all enge Radioallergo sorbent test

Elimination diet Basophil hi stamine release assay (B HR)

Table 2 - Symptoms of food all ergy syndr01ne 17

Mild syste mi c reactions

2 Moderate systemic reactions

3 Severe systemic reactions

4 Life threatening sys temic reactions

Generalized urticaria , pruritus , rhiniti s

Angioedema , dysphrecea, abdominal pain, diarrhoea, nausea, vomitting, ve rti go

Severe diarrhoea, dyspnea , with wheezing

Anaphylac ti c shock, severe breathing difticulties, cyanosis, hypertension , and loss of consciousness

the subject, a few studies have demonstrated cross reac tivities of grapes, apple, peas and peach with some pollen allergens such as, artemesia and birch.

Recently patients showing sensiti vity to latex allergen were also found to be allergic to banana, melon, avocado etc. Papaya, a commonly consumed food, has been shown to cause allergic react ions in a few patients. The enzyme papain from papaya which is used as a tenderizer for meat is the major allergen. Thi s can cause allergic reactions in sensiti ve patients on consumption of such tenderized meat. IgE-directed against papai n can cross-react wi th other proteases such as bromalin from pineapple. Active papain and not the inactive papain elicited ri se in IgE antibodies . Allergen from oranges, cherry, banana, papaya and avocado and sapota have been identifi ed and some of them have been characterized .

Patients allergic to grass pollens are reported to be allergic to Rosaceae fruits such as apple , peas and peach 19

. A few allergens specifi c to fruits such as peach and kiwi , sapota (Achras 7.apara ) have a lso been reported. An unusual case of anaphylax is to mannitol arising out of inges tion of pomgranate fruite has been reported from Mysore20

.

Recent reports indicate that onl y a few cross­reacting allergens are responsi ble for the symptoms caused by a large series of vegetable foods in subj ects with pollenosis, defined as pan al lergens. Many of these allergens belong to a family of prote in s involved in defence aga inst pathogens or in fertilization of plants or structural prote ins such as profillins21

. Major a ll ergens from birch pollen Bet V2,

apple Mal A2 and celery Apig2 are profillins. lt seems that profillins are very effi c ient in sensitizing but less efficient in induc ing clinical symptoms.

GANGAL & MALIK: FOOD ALLERGY 759

Under the vegetables group parsley, carrot, bell pepper, and potato allergens have been characterized and have shown cross-reactivities with pollen of di stinct species. Data on indigenous fruits and vegetables a llergy is not yet available in India. A few reports on oral reactions immediate ly after consumption of fruits such as apples, oranges, grapes and sapota are published

22.

Milk and Milk Products

Cow or buffalo milk is among the first foods introduced to infants in most parts of the world and is one of the most common causes of food allergy in young children. It may be noted that lactose intolerance is different fro m true milk allergy . Most of the studies reported on cow milk from several western countries and Australia have shown that 2.5 per cent of neonates experience hypersensi tivity reactions to cow's milk in the first year of life23

. Both IgE and non IgE mediated reactions account for half of the milk allergy disorders each. The children whose symptoms were not med iated through IgE normall y come out of their sensi tivity by the third year of their life. It has been reported that 15 per cent of infants with IgE med iated milk allergy retai n the ir sensitivity and may develop allergic reactions to some other foods 23

.

Milk is consumed as fluid , cheese or curds e tc and commonly used in various sweets in India. Traces of milk or milk protei ns mixed with other foods in the diet can cause anaphylactic reactions in milk sensiti ve children Milk induced eczema is the first s1gn of allergy in children.

Casein, lactalbumin and lactoglobulin are the major allergic prote ins of milk and they have been characteri zed24

. Although all ergy to buffa lo milk which is consumed in thi s part of the world is not investigated properly , the cross reactivity between proteins in cow, goat, and sheep has been reported. Casein which constitutes 80 per cent of milk proteins is the most allergenic milk protein2

·' .

There are reports that a low IgA content in human milk may lead to defective exclu sion of milk antigens and thus predi spose an offspring to develop food allergies26

.

Eggs and Egg Products

Chicken egg is one of the most common causes of food allergic reactions in children and even in

adults. Egg allergy has been diagnosed in many children and adults in India. The egg yo lk is considered less allergic than the white porti on . However livetin from egg yolk has been implicated in causing allergic symptoms. Ovomuco id (Gal d 1) ,

Ovalbumin (Gal d2), Ovtransferin and lysozyme have been identified as major allergens 111 eggs27

.

Ovomucoid has been identified as a common allergenic prote in. Sun dried or vaccum dried egg white powder has been used in many food preparations inc luding icecreams and suc h foods are therefore necessary to be avoided by egg a llergic patients to avoid any anaphylactic reaction . Wheezing, tightness in the chest, cough, rash and gastrointestinal symptoms, and cramps, have been reported in patients shortly after eating eggs .

Legumes

In western countries especia lly in the US a llergic reacti ons to peanut and soybeans are amongst the most common in children and adults. Many persons suffer severe anaphylactic reac tions due to the inadvertent consumption of peanuts in some f 2s 29 L · f · · orm · . egumes are Important source o prote m 111

vegetarian diet in Indi a. The pulses such as black gram, cajan pea, french bean, horse gram, green gram and lentil s from Leguminosae famil y are used commonly in Indian diet. Green peas, navy beans, dais such as lentil s, urad , and gram have shown mild or severe anaphylactic reac tion s in many atopic patients6

. Very severe anaphylacti c reac tions have been reported due to the consumption of gram by sensitive subjects. Most of these subjects have shown severe gastric or asthmatic symptoms. Dermal reac tions have also been reported in some patients . Peanut, soybean and dat ' ' a llergic prote ins have been well characteri zed. Sixteen allergic fractions have been identifi ed in raw peanuts by CRIE and 8-10 in Bengal gram . Stored peanuts can also contain aflatoxins which can be hi ghly toxic and known to be carcinogenic. In peanuts 32 prote in bands have been identified on SDS-PAGE with molecular weights of 14-64 kda, out of which Arah I , Arah 2 and Arah 3 have been identified as major allergens32

' :n _ However peanut allergy is not common in Indi a.

Soybeans are used in many countries including Indi a because of their hi gh protei n content, DBPCFC studies have demonstrated that soybean can cause a llergic reactions. Even pressed oi l from soybean and

760 J SCI IND RES VOL 62 AUGUST 2003

peanuts were found to retain some of their allergenic potential but refined oils were safe. More recently soybean has been identified also as an occupational aeroallergen inducing asthma. Soya vicillin, homologous to peanut vicillin, has also been reported to be a major soya allergen. Four major protein fractions of soyabean have been isolated and studied for allergenicitl4

. Gly m I A and Gly m I B have been identified as responsible for soyabeen induced asthma. Thermal denaturation of soyabean protein does not affect lgE and IgG specific binding activity35

. A case of fatal anaphylactic reaction has been reported28

. It has been reported from Sweden that soyabean allergy is underestimated as a ri sk factor for severe reactions29

.

Among legumes extensive cross reactivity has been reported by in vitro methods. However most peanut allergic patients did not show allergic

. . f h I 16 reactions on consumptiOn o ot er egumes· .

The members of the legume family can provoke immediate hypersensitivity reactions in susceptible individuals. Further the dietary habits of people likely influence the food sensitivities found in different countries30

.12

.

In India, where majority population is vegetarian, the diet consists mainly of cereals, pulses and vegetables. Due to economic reasons, even the non-vegetarian's diet consists mainly of cereals and pulses with egg, fish , chicken etc. consumed in moderate quantities, twc,-to-three-times a week. Red gram (Cajanus cajan), lentil (Lens esculenta) , black gram (Phaseolus munf?O), green gram (Phaseolus aureus), pea (Pisum sativum) and chickpea (Cicer arietinum) are the major pulses used in the diet of an average Indian. Among these legumes, chickpea is the most common, especially in its flour form, consumed in a variety of preparations. Chickpea flour is mainly used as a thickening agent.

Roasted and puffed chickpea is a popular snack for most Indians. A study was undertaken for the chickpea hypersensitivity cases. It was diagnosed with skin tests, double-blind placebo-controlled food challenges (DBPCFCS) and ELISA in 59 patients who indicated positive histories to chickpea. The major allergies in chickpea-sensitive patients have been detected with immuno-blotting. It was concluded that chickpea is an important source of allergen that can cause IgE-mediated hypersensitivity

reactions ranging from rhinitis to anaphylaxis. The work was also done on the identification and characterization and characterization of cic a I a major chick pea allergen m the Indian subcontinent64

·65

.

Cereal

Cereal s are the main ingredient of Indian diet and consumed in different forms in daily meals. Double blind placebo control food challenges (DBPCFC) studies conducted in atopic dermatitis patients demonstrated that 80 per cent patients reacted to only one grain. Cereals such as rice, wheat, rye, barley and oat have been reported to give allergic reactions in western countries and Japan in many atopic patients, as shown by extensive RAST and skin test reactivity. In Indian population, there are no published reports on allergy caused due to ingestion of cereals. Systematic work needs to be conducted to find the frequency of allergic reactions to cereals in Indian population. This will assume importance with the introduction of transgenic plants and GM foods in India. Asthma caused by ingestion of wheat has been confirmed in many food sensitive patients in other countries38

. Exercise induced anaphylactic reaction to grain flour ingestion has been reportedw-4 1

• IgE antibodies have been found against globulins glutenins present in wheat. In Coeliac disease, gliadin, a 70 per cent alcohol soluble component of wheat, is the responsible component and is a cell mediated reaction. Glutenin sensitive enteropathy is a mal-absorption syndrome characterized by anemia, diarrhoea, and bone pain and thi s is treated with specific diet. Cross-reactions exist among cereal grains and grass pollen in children with food hypersensitivity42

. Wheat a-amylase inhibitor has been reported to give allergic reaction. Several proteins with sequence similarity in a single protein family were identified as major allergens in rice, wheat and barle/3

.

Rice allergen Ory s I, a major allergenic protein in rice, shows considerable similarity to barley trypsin inhibitor and wheat a-amylase inhibitor43

.

Rice grains are source of food allergens in atopic dermatitis whereas wheat and barley flour are source of inhalant allergens in asthma. Rice 16-kda allergen has been studied in great detail including its structure by Japnese workers. Barley Hor vi, a 14.5 kda endosperm protein, has been identified as a major allergen in barley44

.

GANGAL & MALIK: FOOD ALLERGY 761

Structural and eDNA sequence data of allergenic prote ins in cereals suggested that most of

these a llergens from cerea ls be long to a­amylase/trypsin inhibitor famil y. New low all ergenic strains of rice allergen have been produced by biotechnologica l methods45

. However, bi otin defic iency has been observed in an in fa nt fed amino ac id formul a and hypoallergic rice46

. Food a llergy to cereals is rare in western countries but eastern Asian countries where cereals are the staple food allerg ic reactions to cereals should be watched.

Sea Foods

Many indi vidua ls show a wide range of allergic reacti ons such as abdomina l di scomfort to anaphylaxi s and oral a llergy (itching of mouth angioedema of li ps, tongue e tc .), after consumpti on of certain varieties of fi sh or she llfi sh47

"48

. Cod fi sh a llergen Gad c I has been reported to be a sma ll protein be longing to co-binding paralbumin49

.

Salmon Sal s I has been shown to be a maj or a llergen of Atl antic sa lmon fi sh50

. Many of the a llergens from fish and crustaceans are heat stable and res istant to proteases. A severe case of fatal allergy in which the fi sh sens iti zed patient died after eating potatoes fri ed in the same pan used for fi ~ h has been reported by Yuninger

1.

The presence of cross-reac ting heat stable allergens in cru stacean food was first reported by Hoffman et al.1"

51s" .

A maj or a llergen tropomycin , the musc le protein, has been identified and characteri zed from Indi an shrimp (Penaeus indicu::./.

Although India has a large sea coas t and a vast population regul arl y consume fi sh and she ll fi sh only a few iso lated studies on fi sh a llergy have been reported. Thi s however does not mean absence of sea food allergy in India.

Tree Nuts and Seeds

In India lots of dry fruit s are consumed in different forms. Hazelnut, cashewnut , a lmonds have been shown to e lic it a lle rg ic reacti on in a few atopic patients. There is evidence of inc reasing inc idence of a llergic reactions to some foods espec ia ll y peanuts66

.

It is reported that patients with peanut or tree nut allerg ies are faced with several chall enges when eating in restaurants and other food establi shments

a lthough particul ar types of cui sine (e g, Asian ) and particular types of foods (e g, baked goods and ice creams) pose particul ar ri sks54

. Tree nuts are among the most common foods' to cause allergy in S d. . . <; 4. 'i(, Y . f I d. d can mav tan countnes· · . ungmger et a : stu te cases of food re lated fata l anaphylax is invo lving one of the patients a ll ergic to pecan. Anaphylact ic reacti ons to walnut57 .:~x and cashew nut have been

reported in many pati ents. Brazil nut prote in was identified as an allergen in soyabean that had been genetically modified to express braz il nut 2S albumin

f h. . 'iR 67 A . as a source o met tontne· · . s a consequence, tht s transgenic soyabean was re moved from the market. Neoallergens appearing during storage of food s may also cause anaphylacti c reac ti ons as reported in peacan nut.

Informati on on seed a ll ergy is scanty however there are case reports of anaphylactic reactions to sunflower seed59

, sesame seeds, poppy seeds, cotton and mustard seeds. It is therefore necessa ry to study the new genetic engineered pl ants suc h as Bt-cotton from thi s angle as the cotton seed mea l or o il a re used in some foods and allergenic princ iple could come in some form even through the mil k of cattl e consuming such seeds. Sesame seeds cou ld cause severe anaphylactic reacti ons60

. Mustard seed a llergen is a seed storage prote in . T wo maj or a ll ergens from mu stard seeds have been c haracte ri zed . Anaphylax is caused by cotton seed-prote in conta ining candy ingested on a commerc ial airliner has been reported.

Allergy to Oral Drugs and Food Additives and Functional Foods

Many ingested drugs show a ll erg ic reac ti ons in atopic individu als. Common drugs suc h as, sulph a aspirin , some antibi otics , and nit rates show a llergic reacti ons in many pati ents . Cutaneous symptoms include urticaria, angioedema, rash; gastrointestinal symptoms that includes prus itu s, swelling of the eyes, and tongue; respiratory symptoms inc lude rhini tis wheezing etc . Some reacti ons could be pseudo a ll ergic non-IgE mediated. Even allerg ic reacti ons to intravenous injecti on of dye used fo r d iagnosis have been reported . Certa in antibiotics suc h as pe nc ill in are known to produce severe anaphylacti c reacti ons on injecti on and such patients may e lic it c ross

reacti vity to other ~-l actam antibi oti cs. Pri vate prac titi oners have almost stopped using penc illin in India.

762 J SCI IND RES VOL 62 AUGUST 2003

Diagnosi ng an a ll ergy or intolerance to additi ves norma lly in volves carrying out dou ble blind pl acebo contro lled ora l provocati on tests w ith food additi ves. T he a llerg ic reacti ons to food additi ves part icul arl y occur aga in st additi ves that are organic in natu re.

Food additi ves such as caramine, te trazine dyes used as food co lors in medic ines, cosmetics and

t p . sweets are known to cause food anaphylax is after inges tion. Anaphylac tic reac tions due to ingesti on of caramine conta ining food suc h as yogurt , campari have been identi fied , and spec ific anti bod ies to caramine have been detected6 1

• Reports of sul phite triggered asthmatic reacti ons in some sensiti ve patients captured the attention of food quality regu lato rs and use of sulphite in foods IS now reduced .

Functi onal foods are getting popul ar as health supple ments. There have been reports of a llerg ic reacti ons to such processed mi xtures of foods. Hence in safe ty assessment of such foods, a ll e rgenic ity needs to be assessed .

Selection of Allergenic Foods for Product Labelling

Se vera l reports on food allergic reacti ons after consumption of minute amounts of a llergenic foods lead ing occas iona ll y to life threatening cond iti ons have lead to the idea of labe ling the foodstuff fo r the presence of kn own allergenic components. Various government regulatory agenc ies have taken increased notice of food a llergies . Canad ian labe ling regulations require that package food products contain a li s~ of ingred ients that includes spec ific dec larati on of maj ority of components of that product and enforced food product recall s because of the unlabe lled presence of allergenic foods in the produc{'3. In western countri es especia ll y in the US food a lle rgies have become an important food safe ty issue. Three conferences for the South As ian reg ions have been organi zed under globa l FAO/ILSI cooperati ve framework to focus on the issues requiring attenti on of scienti sts, researchers, po licy make rs, agriculture and industry in the South Asian region. Because of g lobalizati on of food trade it is necessary to foc us attenti on on the qua lity of the imported food to prov ide adequate assurance of safety to the consumers. Currentl y ava ilable in formation on food a lle rgy in India and South As ian Region is insuffic ient to enfo rce any labe lling of allergenic

foods. The food industry could at least start indicating the composition of the pac kage food on the labe l, to begin with .

Genetically Modified Food (GM foods)

Several crops are be ing modified by genetic engineering techniques for improved agronomic characteri stics or for improving nu triti onal qua lity of foods. Genetic modificati on ultimate ly results in the introduct ion of new prote ins, and the ir safety inc luding potential a llergenic ity needs proper assessment. Targeting a sing le nutri ent has been shown to result in other a lterations and there is a concern of the potentia l hazard on consumption of such foods. Transgenic soybeans contammg methi onine/cyste ine ri c h prote in of Brazil nut (a potent a llergen) have been c ited as an example of how an a llergen from one food can get transferred into another thereby inc reasing ri sk of its a llergen ic ity.

However, these problems are focused and methods to evaluate safe ty of such GM foods are be ing introduced . It is easier to eval uate safety of GM foods if the gene source is known.

Certainly the products of agricultural biotechnology should be subjected to a careful and complete safety assess ment before commerc iali zation and they need be properl y labe lled.

Therapy for Food Allergy

The only proven therapy is the stric t e liminati on of the offending allergen. However it can have side effects also, li ke malnutriti on. It is rea lly very d ifficult to observe stric t e limination especia lly in Indi a where prepared food is a complex mixture. Because of lack of c linical data from food, challenges a llerg ists often recommend die tary restric ti ons to a ll cereal grains in patients with poss ible sensiti vity to at least one grain .

Severa l drugs have been used to protect patients with food allergy such as, HI 1-12 antihistamines, steroids, and sodium chromoglyate . However they only give short-term effect or no measurable effect. T he effi cacy of immunotherapy in food a llergy is still controvers ial and could occasionally produce severe systemic reactions.

There have been many conflic ting reports suggesting breast-feeding could prevent atopy and

GANGAL & MALIK: FOOD ALLERGY 763

food allergy. However it is now known that breast milk contains varying amounts of cytokines and immunoglobulins which the infant gets initially from the mother, and therefore may give conflicting results. Postponing introduction of food antigens up to 4-6 months is now promoted in several countries as a means of preventing food a llergy . In India, in traditional system, foods other than breast milk are substituted later, after 3-4 months. This probab ly may have been the cause of lower prevalence of food allergy in children in India.

The criteria of pl ac ing a food on the li st of allergenic food s have been formulated by Bousquet et al. 17 as follows:

(a) Report of a properly conducted DBPCFC study confirming allergenicity .

(b) Reports of assessment of the severity of the reaction in foodstuffs causing severe sys temic and life threatening reactions should be li sted.

Indian food habits are different from those in western hemisphere as Indians eat a lot of complex mixtures of foods. Several spices make up flavour of a food . Also no systematic studies have been conducted on the prevalence of food allergy and the major allergenic common foods in Indian population and prevalence of severe food a llergies is poorl y understood. The high-ri sk allergenic foods reported in the western literature have not been found to show similar ri sk of suffering an allergic reacti on in Indi an population.

Conclusions

In summati on, studies on food allergy are in its infancy in India, and need to be conducted systematically . The public, the media, the med ical community and the food industry should be aware of the potential for allergic reactions inc luding anaphylactic from inadvertent consumption of specific offending food by a food allerg ic indi vidual.

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