What is the cause of food allergies
Restaurants are responsible for food allergies in some circumstances. The restaurant has a extremely high duty of care for their customers. They should be aware of common food allergies and assist customers understand the ingredients in their products.
However, negligence applies to consumers, too. Restaurant patrons also own a role to frolic in avoiding known allergies. However, when the restaurant acts negligently towards its patrons and harm results from an allergy, the restaurant may be legally liable to the victim for their damages.
Legal Standard for Restaurant Allergen Liability
There are multiple legal theories for food allergen victims:
- Failure to warn – A restaurant is selling a product — its meals.
Along with producing a product, they own a legal obligation to give patrons the information that they need to use the product safely. Failure to warn is a helpful of products liability. When a restaurant doesn’t provide the necessary information so that consumers can make informed choices, failure to warn may be the legal theory for financial responsibility.
- Negligence – Restaurant owners own the legal obligation to conduct trade with ordinary care. They must take steps to ensure that the meals that they serve their customers are safe.
Negligence is a lack of reasonable care. The restaurant has to use an quantity of care that’s reasonable for a restaurant.
They don’t own to prevent any helpful of accident or harm, but they own to take enough steps to hold customers safe. The standard is fairly high because a restaurant is a for-profit business.
- Intentional tampering – Sometimes, restaurant staff will purposefully tamper with food. A bad reaction to a food allergen can give rise to an intentional tort claim. When people act purposefully to hurt others through food, intentional tampering can be the grounds for a lawsuit.
Can a Restaurant Be Liable for Food Allergies?
Yes, a restaurant can be liable for food allergies.
Whether a restaurant has legal liability or harm caused by a food allergy depends on whether the restaurant was negligent. If the customer expresses concerns that go unaddressed or if the restaurant fails to take precautions for common allergies, they may be liable to a customer when harm results from a food allergy.
Allergy and Intolerance
Recommendations for children considered at higher risk of developing food allergy
Children with a family history of allergy are at a higher risk of developing a food allergy, and there are certain recommendations that include:
- Exclusive breastfeeding for the first six months of life
- Weaning foods to be introduced one at a time with a period of at least one day between new foods so that symptoms can be monitored
- Around 5-8 % of children will develop a true food allergy and up to 90% of children will grow out of these allergies, often by five years of age.
They may however go on to develop other allergy related conditions, such as asthma, eczema, hay fever or rhinitis, later in life
- A food allergy involves the immune system and often causes an immediate reaction after consumption of the food allergen (something in the food that causes an allergic reaction)
- The most common symptoms of a food allergy are irritation of the skin and eyes, swellings around the eyes, mouth and tongue, sneezing and blocked or runny noses, shortness of breath and coughing, abdominal pains, diarrhoea and vomiting
- The foods that most commonly cause food allergies are; eggs, cows’ milk, nuts, wheat, fish, shellfish, peanuts and soya
- Lactose intolerance is an example, where there is a lack of or a reduced quantity of the enzyme which is needed for lactose digestion
- Food intolerance is any adverse response that happens each time a food is eaten
- A food intolerance is often a more delayed reaction, generally occurring hours or even days after eating certain foods
- Food intolerance symptoms often involve the digestive tract and include pain and colic, bloating, wind, diarrhoea and sometimes vomiting
What are they and what to do if you suspect your kid has one
The prevalence of allergies has increased greatly over the final two decades, although experts are still trying to discover exactly why
- Children are more at risk of developing an allergy if they own a parent or shut relative that has asthma, eczema, hay fever or food allergy
- Cows’ milk protein allergy is the most common food allergy in children, as cow’s milk is the major food that a bottle-fed kid is given.
Many mums worry about their children reacting to the foods they give them or developing an allergy.
Allergy and intolerance are two distinct conditions and should not be confused.
Allergy or intolerance to cows’ milk
- Symptoms of the two can be similar and include eczema or rashes, diarrhoea, vomiting and stomach cramps. Lactose intolerance will not produce hives or breathing difficulties
- Children can react to cows’ milk, baby formula based on cows’ milk, or even breast milk if cows’ milk or dairy products own been consumed by the mother
- If cows’ milk is causing symptoms in your kid, it is significant to determine whether it is the protein or the lactose (a milk sugar) which is causing the problem, as this will determine the type of dietary restrictions they will need
- A lactose intolerance will not show up in conventional allergy testing love a skin prick test or blood test
If you suspect your kid has a food allergy or intolerance
It is really significant that if you suspect that your kid has had an adverse reaction to a food, you should seek professional medical advice.
If an allergy or intolerance is diagnosed you will then be given assist to formulate a suitable diet for your kid which ensures that their diet continues to meet their nutritional needs.
Centuries ago, Lucretius said that one man’s food may be another man’s poison. Such is the case with food allergies. Individuals with food allergies and other types of food sensitivities react adversely to the ingestion of foods and food ingredients that most consumers can ingest with no problems.
Eating is necessary to sustain life. For most consumers, eating is an enjoyable experience given the variety and abundance of foods available in the marketplace.
For some individuals, however, consuming certain foods can be a debilitating, possibly even life-threatening, experience. Individuals with various forms of food allergies and sensitivities must avoid certain foods or food ingredients in their diets. For such people, the joy of eating is diminished by the ever-present concern that they might consume a food or food ingredient that will elicit an adverse reaction.
For them, food selection can become a tedious task requiring the painstaking reading of ingredient lists on the labels of packaged foods and a ceaseless search for more knowledge about food composition. Food preparation requires careful attention to details such as “cooking from scratch,” seeking alternative recipes for numerous dishes, and avoidance of shared utensils, containers, and cooking surfaces between allergenic and non-allergenic foods.
In situations where one family member has a extremely serious allergic sensitivity, the entire family often has to avoid the offending food as a precautionary measure.
Food allergies and other food sensitivities are individualistic adverse reactions to foods (Taylor, 1987). These food-related illnesses are individualistic because they affect only a few people in the population; most consumers can eat the same foods with no ill effects. Numerous diverse types of reactions are involved in these individualistic adverse reactions to foods (Fig.
1; Anderson, 1996; Taylor, 1987). Adverse food reactions can include IgE and non-IgE-mediated primary immunological sensitivities, non-immunological food intolerances, and secondary sensitivities. While these various types of reactions are often considered collectively as food allergies, true food allergies represent only a part of the individualistic adverse reactions to foods.
True Food Allergies. True food allergies are abnormal (heightened) responses of the immune system to components of certain foods (Lemke and Taylor, 1994).
The components of foods that elicit these abnormal immune responses are typically naturally-occurring proteins in the foods (Bush and Hefle, 1996). True food allergies can be divided into two categories based upon the nature of the immune response—immediate hypersensitivity reactions and delayed hypersensitivity reactions (Lemke and Taylor, 1994). In immediate hypersensitivity reactions, symptoms start to develop within minutes to an hour or so after ingestion of the offending food.
Immediate hypersensitivity reactions own been noted with numerous foods and can sometimes be fairly severe (Hefle et al., 1996). Immediate hypersensitivity reactions involve abnormal responses of the humoral immune system with the formation of allergen-specific immunoglobulin E (IgE) antibodies (Mekori, 1996). In delayed hypersensitivity reactions, symptoms do not start to appear until 24 hours or longer after the ingestion of the offending food (Lemke and Taylor, 1994). With the exception of celiac disease, which involves an abnormal immunological response to wheat and related grains (Ferguson, 1997), the role of delayed hypersensitivity reactions to foods remains poorly defined.
Delayed hypersensitivity reactions involve abnormal responses of the cellular immune system with the development of sensitized T cells (Lemke and Taylor, 1994).
Allergy-Like Intoxications. Certain foods can elicit adverse reactions that resemble true food allergies. These foods contain elevated levels of histamine, one of the principal mediators of allergic reactions in the body (Taylor et al., 1989a). In true food allergies and anaphylactoid reactions, however, histamine is released from intracellular locations (Mekori, 1996).
In these allergy-like intoxications, histamine is ingested with foods. Histamine poisoning is often known as scombroid fish poisoning because it is frequently associated with consumption of spoiled fish of the scombroid type such as tuna and mackerel (Taylor et al., 1989a). However, histamine poisoning can also happen from the ingestion of spoiled fish such as mahi-mahi and bluefish that are not scombroid fishes (Etkind et al., 1987; Taylor et al., 1989a). And, histamine poisoning has even been occasionally associated with the ingestion of cheese, especially aged Swiss cheese (Stratton et al., 1991; Taylor et al., 1982).
In every of these food products, specific types of bacteria own proliferated and caused the conversion of the amino acid, histidine, into histamine (Stratton and Taylor, 1991; Sumner et al., 1985; Taylor et al., 1978). Ingestion of little amounts of histamine in the diet is a normal occurrence and does not cause any harm. However, when large doses of histamine are ingested with foods, the body’s protective mechanisms can be overwhelmed resulting in histamine poisoning (Taylor, 1986). Unlike food allergies and sensitivities, every consumers are susceptible to histamine poisoning.
Because this illness is not truly a form of food allergy or sensitivity, it will not be discussed further. It does merit some mention because the similarity in symptoms can cause it to be confused with true food allergy.
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Food Intolerances. Food intolerances are abnormal reactions to foods or food components that do not involve the immune system. Several diverse types of food intolerances are also known to exist. These intolerances are metabolic food disorders, anaphylactoid reactions, and idiosyncratic reactions (Taylor, 1987). Metabolic food disorders are adverse reactions to a food or food component that results from a defect in the metabolism of these foods or some substance therein or from an affect of the food or food component on the body’s normal metabolic processes.
Lactose intolerance is an example of a metabolic food disorder resulting from a defect in the metabolism of a food component (Kocian, 1988). Favism is an example of a metabolic food disorder resulting from foodborne substances that interfere with normal metabolic processes (Mager et al., 1980). Anaphylactoid reactions are adverse reactions resulting from the ingestion of foodborne substances that release histamine from cellular stores within the body (Taylor, 1987). There are no particularly excellent examples of anaphylactoid reactions, although circumstantial evidence suggests that such reactions may happen. Food idiosyncrasies are adverse reactions to foods or food components that happen through unknown mechanisms and which can even include psychosomatic illnesses (Taylor, 1987).
Sulfite-induced asthma is the best example of an idiosyncratic reaction that has been well documented to happen among certain consumers, although the mechanism remains unknown (Bush and Taylor, 1998).
Secondary Food Sensitivities. Adverse reactions to foods or food components can happen with or after the effects of other conditions. Examples of such reactions, termed secondary food sensitivities, include lactose intolerance secondary to gastrointestinal disorders such as Crohn’s disease or ulcerative colitis (Metcalfe, 1984a) and drug-induced sensitivities such as the increased sensitivity to tyramine among patients on monoamine oxidase-inhibiting drugs (Blackwell and Marley, 1969).
IgE-Mediated Food Allergies
This type of food allergy can also be called immediate hypersensitivity, Type I allergy, or food anaphylaxis.
The Greek expression, anaphylaxis, means “against protection” and refers to allergic reactions to foreign protein molecules. IgE is one of five classes of antibodies that are present in the human body and that frolic a role in disease resistance. IgE antibodies are particularly involved in fighting off parasitic infections. Although every humans own low levels of IgE antibodies, only individuals predisposed to the development of allergies produce IgE antibodies that are specific for and recognize certain environmental antigens. These antigens are typically proteins, although only a few of the numerous proteins in nature are capable of stimulating the production of specific IgE antibodies in susceptible individuals (Taylor, 1996).
The allergens eliciting IgE antibody formation can be found in pollens, mold spores, bee venoms, dust mites, and animal danders in addition to foods (Solomon and Platts-Mills, 1998).
Pathogenesis. The mechanism of IgE-mediated allergic reactions is depicted in Fig. 2. First, sensitization by the allergen must happen. In the sensitization phase of the response, the allergen stimulates production of specific IgE antibodies. While sensitization can happen with the first exposure to the allergen, that is not always the case. With honor to food allergens, sensitization does happen most commonly among young infants where the immune response seems to be more likely to be oriented toward an IgE response (Anderson, 1996).
However, even in susceptible infants exposure to most dietary proteins results in oral tolerance, a normal immunologic response that is not associated with adverse reactions, rather than sensitization (Strobel, 1997). The specific IgE antibodies then attach to mast cells in various tissues and basophils in the blood. Mast cells and basophils contain granules that are loaded with physiologically athletic chemicals that mediate the allergic response (Church et al., 1998). On subsequent exposure to the allergenic substance, the allergen cross-links two IgE antibodies on the surface of the mast cell or basophil membrane, stimulating the release into tissues and blood of a host of allergic response mediators.
Although numerous mediators own been described, histamine is one of the primary mediators responsible for numerous of the immediate symptoms that happen in IgE-mediated allergic reactions (Simons, 1998). Other significant mediators include the various leukotrienes and prostaglandins, some of which are associated with more delayed symptoms that can happen in IgE-mediated, immediate hypersensitivity reactions, the so-called late-phase responses (Peters et al., 1998).
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IgE-mediated food allergies are associated with a wide variety of symptoms, ranging from mild and annoying to severe and life-threatening (Lemke and Taylor, 1994). The symptoms can involve the gastrointestinal tract, skin, or respiratory tract (Table 1). Food-allergic individuals generally suffer from only a few of the numerous possible symptoms. The nature and severity of the symptoms experienced by a food-allergic individual may also vary from one episode to the next depending on the dose of the offending food that has been inadvertently ingested, the degree of sensitization to the offending food at the time of the episode, and probably other factors.
Because foods are ingested, gastrointestinal symptoms are often encountered (Anderson, 1996; Gryboski, 1991). However, these symptoms can also be involved in other illnesses so their association with food allergies is often hard to decipher. Cutaneous symptoms such as urticaria (hives) and dermatitis (eczema) are also common manifestations of food allergies (Kaplan, 1998). These symptoms are more definitive for food allergy, although the frequency of dermatitis as a manifestation of food allergy especially, in infants, has only been widely appreciated in the past decade or so (Sampson, 1988). Respiratory symptoms are less commonly associated with food allergies than with environmental allergies such as pollen or animal dander allergies (Taylor et al., 1999).
With environmental allergies, the allergens are inhaled, so the primary involvement of respiratory symptoms is understandable. However, ingested food allergens must survive digestive processes and be absorbed to elicit systemic reactions in the respiratory tract. Although few asthmatic individuals experience food-induced asthma, asthma is among the most severe symptoms associated with food allergies (Bousquet and Michel, 1988). Food-induced asthma is a risk factor for severe, life-threatening reactions to the offending foods (Sampson et al., 1992).
Oral allergy syndrome is perhaps the most common manifestation of food allergy (Ortolani et al., 1988).
Oral allergy syndrome is often so mild that it is ignored by afflicted individuals. Oral allergy syndrome involves symptoms confined to the oropharyngeal area including hives, itching, and swelling (Pastorello and Ortolani, 1997). Unused fruits and vegetables are the foods most frequently associated with oral allergy syndrome (Pastorello and Ortolani, 1997). Individuals with oral allergy syndrome are generally sensitized to one or more pollens, and react to proteins in specific unused fruits and vegetables that cross-react with the pollen allergens (Calkoven et al., 1987; Ebner et al., 1995; van Ree and Aalberse, 1993).
Examples would include allergic reactions to watermelons and other melons in ragweed-allergic individuals (Enberg et al., 1987), allergic reactions to celery in mugwort-allergic or birch-sensitized individuals (Ballmer-Weber et al., 2000; Wuthrich et al., 1990), and allergic reactions to apples and hazelnuts in birch-allergic individuals (Dreborg, 1988). Because the allergens in these foods are inactivated on contact with stomach acid and digestive proteases, systemic reactions to these unused fruits and vegetables are rarely encountered (Taylor and Lehrer, 1996). Because these allergens are denatured by heating (Dreborg and Foucard, 1983; Taylor and Lehrer, 1996), individuals with oral allergy syndrome can generally safely ingest heat-processed forms of the offending food, e.g., apple jelly or apple sauce.
Recent evidence indicates that, in contrast to previous assumptions, some individuals with oral allergy syndrome associated with certain foods, such as celery, also may experience more severe systemic reactions on occasion (Ballmer-Weber et al., 2000).
The most frightening symptom associated with food allergies is anaphylactic shock, which generally involves multiple systems including the gastrointestinal tract, the skin, the respiratory tract, and the cardiovascular system. Symptoms happen in combination and develop rapidly. Severe hypotension can happen. Death can happen from cardiovascular and/or respiratory collapse within minutes of ingestion of the offending food.
Only a few of the numerous people with IgE-mediated food allergies are at risk for such serious manifestations. However, numerous deaths own been attributed to inadvertent exposure to the offending food among individuals with food allergies (Bock et al., 2001; Sampson et al., 1992; Yunginger et al., 1988). These deaths own involved asthma and/or anaphylactic shock.
In addition to allergic reactions associated with the consumption of foods, occupational food allergies including occupational asthma, hypersensitivity pneumonitis (extrinsic alveolitis), and contact dermatitis can happen amongst food industry employees (O’Neil and Lehrer, 1997).
Such reactions can be triggered in food manufacturing workers by food-derived protein allergens, e.g., green coffee beans, flour, and shellfish, or non-food agents, e.g., honey bees and latex products (Lehrer and O’Neil, 1992). These occupational allergies are produced by respiratory exposure to dusty processing environments or cutaneous exposure to specific food products.
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With the wide range of symptoms that can be involved in IgE-mediated food allergies and the possibility of other causes for numerous of these symptoms, the diagnosis of IgE-mediated food allergies can sometimes be challenging (Metcalfe, 1984b). First and foremost, an association must be sought between the ingestion of one or more offending foods and the elicitation of the adverse reaction. Once a food-associated adverse reaction is well documented, then proof of the existence of an IgE mechanism must be considered. The assistance of an allergist should be sought in the diagnosis of IgE-mediated food allergies. Too often, consumers rely upon self-diagnosis or parental diagnosis.
Self-diagnosis and parental diagnosis of reactions in children are problematic because they are often erroneous, leading to the identification of the incorrect foods, and implicate too numerous foods (Bock et al., 1978). Careful history-taking including the use of food diaries by an experienced allergist can often identify suspect foods. Elimination diets followed by challenges can sometimes confirm the existence of a food-associated adverse reaction. However, the gold standard for documenting existence of a food-associated adverse reaction is the double-blind, placebo-controlled food challenge (DBPCFC; Bock et al., 1988). Such clinical challenges are especially useful in situations where the role of a specific food remains somewhat questionable.
Double-blind, placebo-controlled food challenges are not generally done in cases involving serious, life-threatening adverse reactions because of the obvious risks to the patient and the likelihood in such cases that the role of one or more specific foods is rather clear. Once the role of one or more specific foods in the adverse reaction has been established, then the involvement of the IgE mechanism can be documented through skin-prick tests using extracts of the suspect foods (Bock et al., 1977) or by radioallergosorbent tests (RASTs) where the presence of food-specific IgE antibodies in the blood serum is examined (Adolphson et al., 1986).
IgE-mediated food allergies likely affect between 2 and 2.5% of the entire population. For numerous years, the overall prevalence estimate for IgE-mediated food allergies has been between 1 and 2% of the entire population (Lemke and Taylor, 1994). However, a recent random, digit-dial telephone survey in the U.S. indicated that the combined prevalence of peanut and tree nut allergies was an estimated 1.14% (Sicherer et al., 1999). And, a similar telephone survey in the United Kingdom indicated that the estimated prevalence of peanut allergy alone was 0.5% (Emmett et al., 1999).
While one could criticize the use of telephone surveys, it is unlikely that numerous consumers would mis-diagnose peanut or tree nut allergies since the symptoms are profound and generally fairly immediate. Thus, these surveys may be reasonably dependable and a excellent indication that previous estimates based solely on clinical impression were incorrect. Certainly, if peanut and tree nut allergy alone account for more than 1% of IgE-mediated food allergy, then the overall prevalence of food allergy in the entire population likely exceeds 2%.
Infants (1–3 years of age) and children are more commonly affected by food allergies than other age groups (Taylor et al., 1999).
Among infants younger than 3 years, the prevalence of food allergies appears to be in the range of 5% to 8% (Sampson, 1990). The prevalence of food allergy among young infants (<1 year of age) has been studied more thoroughly than has the prevalence among older children and adults.
A much higher proportion of the public believes that they own food allergies because of self-diagnosis, parental diagnosis, and misconceptions about the definition of food allergy even among some physicians (Bock et al., 1978; Sloan, 1986).
Studies own shown that 10 to 20% of the consuming public believes that they or someone in their family has a food allergy (Chiaramonte et al., 1999; Sloan, 1986).
Some believe, on the basis of the impressions of clinicians involved in allergy practice for several decades, that the prevalence of IgE-mediated food allergies is increasing. An increase in prevalence, however, is hard to confirm because excellent baseline data from earlier years for comparative purposes are lacking. Certainly, the awareness of food allergy has increased. More individuals may seek specialized medical attention from allergists as a result of this increased awareness.
But, almost everyone agrees that the prevalence of severe food allergies seems to be increasing. The reasons for this apparent increase are unknown. Numerous severely affected individuals own food-induced asthma as one of the manifestations of their allergic reaction. The overall prevalence of asthma is definitely increasing in the U.S. for unknown reasons (Beasley et al., 2000). While food-induced asthma is a little part of the entire asthma population, the prevalence of food-induced asthma may be increasing in concert with the overall increase in prevalence of asthma.
Most Common Allergenic Foods.
The prevalence of allergies to specific foods is not precisely known.
Cows’ milk allergy appears to be among the more prevalent food allergies in infants. This is not surprising given the importance of milk in baby feeding practices. The prevalence of cows’ milk allergy among infants under the age of two in Sweden, Denmark, and Australia has been studied and found to be approximately 2% in every three countries in well-conducted clinical studies involving groups of unselected infants followed from birth to the age of two years (Hill et al., 1997; Host and Halken, 1990; Jakobsson and Lindberg, 1979). The prevalence of milk allergy is known to decrease with age (Bock, 1982), but the exact prevalence of milk allergy among other age groups is unknown.
The prevalence of other specific food allergies has not been established in controlled clinical trials using unselected population groups. The comparative prevalence of various specific food allergies can be discerned from studies involving groups of individuals with probable food allergies. In the U.S., eggs and peanuts are also common allergenic foods for infants, along with soybeans, tree nuts, fish, and wheat (Bock and Atkins, 1990; Burks et al., 1988; Sampson and McCaskill, 1985). Among adults in the U.S., peanuts are probably the most common allergenic food (Taylor et al., 1999). Seafood allergies, especially to crustaceans (shrimp, crab, lobster), are also rather common among adults (Lehrer et al., 1992).
Fewer studies own been conducted on the prevalence of specific types of food allergies in adults in the U.S. or other countries. The prevalence of specific types of food allergies may vary among population groups based upon their eating habits (Taylor et al., 1999). Peanut allergy appears to be more common in North America than in other parts of the world. This observation may relate to the popularity of peanut butter in North America. As other countries, such as the United Kingdom, own adopted the North American affection for peanuts and peanut products, the prevalence of peanut allergy in those countries appears to be rising (Emmett et al., 1999).
Another example would be buckwheat allergy. Buckwheat allergy appears to be rather common among adults in certain southeast Asian countries such as Japan and South Korea (Kang and Min, 1984). In contrast, buckwheat allergy would be rather unusual in the U.S. The difference is likely due to the popularity of buckwheat noodles in the cuisine of certain southeast Asian countries. Such observations own profound implications for product developers. If a highly successful buckwheat product was introduced into the U.S. or if buckwheat noodles became favorite in American Asian cuisine, the prevalence of buckwheat allergy would likely increase.
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The Large Eight.
Eight foods or food groups are thought to account for more than 90% of every IgE-mediated food allergies on a worldwide basis (Bousquet et al., 1998; FAO, 1995). These foods or food groups are milk, eggs, fish (all species of finfish), crustacea (shrimp, crab, lobster, crayfish), peanuts, soybeans, tree nuts (almonds, walnuts, pecans, cashews, Brazil nuts, pistachios, hazelnuts also known as filberts, pine nuts also known as pinyon nuts, macadamia nuts, chestnuts, and hickory nuts), and wheat. In 1995, an expert consultation of the Food and Agriculture Organization of the United Nations sure that these eight foods or food groups were the most common causes of food allergy on a worldwide basis (FAO, 1995).
Subsequently this list was adopted by the Codex Alimentarius Commission in 1999 (CAC, 1999). These foods and food groups own come to be known as the “Big Eight” (Table 2).
More than 160 other foods own been documented as causing food allergies less frequently (Hefle et al., 1996).
Basically, any food that has protein has the potential to elicit an allergic reaction among susceptible individuals. Beyond the Large Eight, in certain geographic regions other foods or food groups may frequently cause IgE-mediated food allergies. Celery allergy, for example, is rather common in some European countries (Wuthrich et al., 1990). The prevalence of buckwheat allergy in southeast Asia has already been mentioned.
And, sesame seed allergy is extremely common in middle Eastern countries and countries where the ethnic population of middle Easterners is high; this may be due to the popularity of tahini, a paste made from sesame seeds, in the diets (Kanny et al., 1996). Several countries including Canada own decided to add sesame seeds to the list of commonly allergenic foods for that country.
A few other foods are worthy of mention because, although they less frequently cause allergies, they own been associated with severe reactions. These foods include molluscan shellfish (clams, oysters, etc.), sesame seeds, poppy seeds, sunflower seeds, cottonseed, and certain other legumes beyond peanuts and soybeans (the various types of dry beans, peas, lentils, and garbanzo beans also known as chick peas) (Atkins et al., 1988; Gall et al., 1990; Kagi and Wutrich, 1993; Kalyoncu and Stalenheim, 1993; Kanny et al., 1996; Maeda et al., 1991; Martin et al., 1992; Noyes et al., 1979). However, a rather large percentage of the 160 or more other allergenic foods has been reported to elicit severe allergic reactions in isolated cases (Hefle et al., 1996).
The allergens in foods are almost always naturally occurring proteins. Foods contain millions of individual proteins, but only a comparative few of the proteins own been documented to be allergens (Bush and Hefle, 1996; Taylor, 1996). Some foods such as milk, eggs, and peanuts are known to contain multiple allergenic proteins (Bush and Hefle, 1996). Other foods such as Brazil nuts, shrimp, and codfish contain only one major allergenic protein (Bush and Hefle, 1996). However, the majority of the proteins, even those from commonly allergenic foods, are incapable of eliciting IgE production.
Although the common allergenic foods listed above tend to be excellent sources of protein, other common protein-rich foods such as beef, pork, chicken, and turkey are rarely allergenic. No common structural features own allowed distinctions to be made between those proteins that are capable of eliciting IgE production and those that are not. Allergenic proteins, however, tend to be major proteins in the implicated foods, resistant to digestion, and stable to processing operations, particularly heat processing (Taylor and Lehrer, 1996).
Development of IgE-Mediated Food Allergies.
Genetics frolic an significant role in the development of IgE-mediated allergies of every types, including food allergies (Kjellman and Bjorksten, 1997). Allergies are much more likely to develop in children born to parents who own allergies (either to food, pharmaceutical, or environmental allergens) than amongst children born to parents with no history of allergies (Taylor et al., 1999). However, the nature of the allergy that develops is not genetically controlled. Therefore, the children of pollen-allergic parents are at increased risk for development of food allergies as are the children of food-allergic parents.
The risk is greater if both parents own allergies than it is if only one parent has allergies.
Infants are the most likely to develop food allergies (Sampson, 1990; Taylor, 1987). However, sensitization to foods can happen at any age. Infants do not appear to develop allergies in utero (Kjellman and Bjorksten, 1997), but can be sensitized during the first few days of life. Obviously, the newborn baby encounters through the first few years of life dozens of new foods and probably hundreds of thousands of food proteins that own antigenic and possibly allergenic potential. For most of these foods and their proteins, infants develop oral tolerance (Strobel, 1997).
Infants appear to be at increased risk for the development of IgE-mediated food allergies in part because their digestive processes may not be fully developed but primarily because they own not yet had the chance to develop oral tolerance. Certain foodborne proteins seem to be much more likely than others to cause allergic sensitization (Bush and Hefle, 1996). The factors involved in sensitization and the development of IgE-mediated food allergies are not yet fully understood.
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Prevention of IgE-Mediated Food Allergies.
The prevention of the development of IgE-mediated food allergies among high-risk infants (those born to parents with histories of allergies) has been a long-sought goal. However, the results of several large clinical trials of high-risk infants followed for several years propose that the development of IgE-mediated food allergies can be delayed but not prevented (Zeiger and Heller, 1995). The maternal diet during pregnancy does not seem to be a factor (Zeiger and Heller, 1995), because sensitization does not happen in utero.
The avoidance of commonly allergenic foods such as cows’ milk, eggs, and peanuts in the baby diet during the first few years of life often delays the development of food allergies, but food allergies may still develop after solid foods are introduced (Hattevig et al., 1989; Zeiger and Heller, 1995). Avoidance can be accomplished through breast-feeding or the feeding of hypoallergenic baby formula (Kjellman and Bjorksten, 1997; Zeiger and Heller, 1995). Numerous pediatricians recommend breast-feeding for infants born to parents with histories of IgE-mediated allergies.
Lactating women can apparently transmit potentially sensitizing levels of food allergens through their milk to nursing infants (Van Asperen et al., 1983). Apparently, intact or partially intact allergenic proteins are capable to survive maternal digestive processes and be absorbed via the lymph and transferred immunologically intact into breast milk (Van Asperen et al., 1983). Infants own been sensitized through breast-feeding to peanuts, cows’ milk, and eggs (Van Asperen et al., 1983). The avoidance of peanuts in the maternal diet during the lactation period is often advocated as a preventive measure.
However, the exclusion of milk and eggs from the maternal diet during lactation is not generally recommended due to their nutritional importance coupled with the low likelihood of allergic sensitization through breast-milk (Taylor et al., 1999). The use of hypoallergenic baby formula to prevent or delay the development of IgE-mediated food allergies is less commonly practiced. However, the use of partial whey hydrolysate formulae for this purpose may show some promise (Vandenplas et al., 1992), although such partial hydrolysates are not safe for consumption by infants who are already sensitized to cows’ milk (Businco et al., 1989; Ellis et al., 1991).
Apparently, the partial hydrolysis of the whey proteins increases the likelihood of the development of oral tolerance as opposed to allergic sensitization.
Natural History of IgE-Mediated Food Allergies. Most food allergies developed in infancy are outgrown in infancy or early childhood. Numerous infants outgrow their food allergies, often within a matter of a few months (Bock, 1982; Hill and Hosking, 1992). Allergies to certain foods such as cows’ milk, eggs, and soybeans are much more likely to be outgrown than allergies to other foods such as peanuts (Bock, 1982; Bock and Atkins, 1989).
Peanut allergy is almost never outgrown. The loss of allergic sensitivity to a specific food probably results from the development of immunological, oral tolerance (Taylor et al., 1986a). However, the basis for the differences between specific foods (e.g., milk vs.
peanuts) in the development of oral tolerance is not understood.
Cross-Reactions between Related Allergenic Foods. Allergic consumers sometimes experience cross-reactions between closely related foods. For example, with the crustacea, most sensitive individuals are allergic to every of the various species of shrimp, crab, lobster, and crayfish (Lehrer, 1986). However, these individuals can often eat other seafoods including finfish and molluscan shellfish.
Similar cross-reactivity also exists between cows’ milk and goats’ milk (Bellioni-Businco et al., 1999) and between eggs of various avian species (Langeland, 1983). With other food groups, the situation can be fairly complicated. For example, peanuts are the most commonly allergenic legumes. Most peanut-allergic individuals can eat other legumes without incident (Bernhisel- Broadbent and Sampson, 1989). A few peanut-allergic individuals are also allergic to soybeans (Herian et al., 1990), although this may not necessarily represent true cross-reactivity. With fish, individuals often experience reactions to more than one species of fish, but some fish are tolerated by some fish-allergic individuals and no definite patterns of reactivity own been identified (Bernhisel-Broadbent et al., 1992; de Martino et al., 1990).
Cross-Reactions between Food and Environmental Allergens.
Cross-reactions are frequently observed between pollens and certain foods, especially fruits and vegetables (Ballmer-Weber et al., 2000; Calkoven et al., 1987; van Ree and Aalberse, 1993; Wuthrich et al., 1990). This is the oral allergy syndrome, which typically involves mild reactions as previously mentioned. Examples include cross-reactions between birch pollen and apples, ragweed pollen and melons, and mugwort pollen and celery (Ballmer-Weber et al., 2000; Calkoven et al., 1987; Enberg et al., 1987; van Ree and Alberse, 1993; Wuthrich et al., 1990).
Cross-reactions own also been noted between latex allergies, a common problem among health-care workers, and certain foods including bananas, kiwis, avocados, and chestnuts (Blanco et al., 1994).
Effect of Food Processing on Allergens. As mentioned earlier, the allergens in foods are typically proteins that are stable to heat processing (Taylor and Lehrer, 1996). So, heat-processed forms of commonly allergenic foods often retain their allergenicity (Herian et al., 1993; Nordlee et al., 1981).
The only exception would be the pollen-related allergens found in unused fruits and vegetables and involved in oral allergy syndrome; these allergens are generally destroyed by heat processing (Dreborg and Foucard, 1983), although the necessary extent of the heat process has not been well documented in most cases. For the most common allergenic foods, every forms of those foods should be considered allergenic unless proven otherwise. Testing has indicated that most forms of peanuts and soybeans, for example, retain their allergenicity (Herian et al., 1993; Nordlee et al., 1981).
Other processing techniques own not been so well investigated for their effects on the allergenicity of the resulting products. Since allergens are resistant to proteolysis, fermentation generally fails to eliminate allergenicity (Taylor and Lehrer, 1996). For example, although fermented soybean products are reduced in allergenicity, some allergenic activity is retained (Herian et al., 1993).
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If the protein part is removed during processing, however, the resulting product or ingredient might be safe because the allergen has been removed.
The classic example is the processing of edible oils from peanuts and soybeans (Bush et al., 1985; Hourihane et al., 1997a; Taylor et al., 1981). Clinical challenge trials in peanut- and soybean-allergic individuals own documented that highly refined peanut and soybean oil are safe for individuals with allergies to the source material (Bush et al., 1985; Hourihane et al., 1997a; Taylor et al., 1981).
Other ingredients may be derived from allergenic sources. Examples include certain flavoring formulations, starch, lecithin, and gelatin.
Flavors can occasionally contain protein residues from allergenic foods (Taylor and Dormedy, 1998). Starch is often made from corn or some other source that is rarely allergenic. Occasionally, starch is made from wheat, although the level of protein residues is fairly low and adverse reactions to wheat starch own not been reported. Lecithin can be made from either soybean or egg and can contain allergenic residues (Muller et al., 1998). However, the degree of risk posed by the low residual levels of soybean allergens in lecithin remains unknown.
Gelatin is most commonly made from beef and pork, foods that are rarely allergenic (Sakaguchi et al., 1996). However, gelatin can also be made from fish skins. The allergenicity of fish gelatin remains unknown (Sakaguchi et al., 1999).
Treatment. Allergic reactions to foods can be treated with certain drugs (Furukawa, 1988; Simons, 1998). Antihistamines can counteract the effects of histamine (Simons, 1998), although these drugs do not counteract the effects of the other mediators released from basophils and mast cells.
Epinephrine (adrenaline) is considered the life-saving drug for individuals at risk of severe anaphylactic shock-type reactions to foods (Sampson et al., 1992). Epinephrine is available in self-injectable form. Consumers with a history of severe anaphylactic reactions to foods should own a prescription for epinephrine and carry the medication at every times. To be most effective, epinephrine must be istered early in the course of the allergic reaction. However, an examination of severe food-allergic reactions resulting in deaths or near-deaths reveals a delay in the istration of epinephrine as a key contributing factor to the severe outcome (Sampson et al., 1992).
The specific avoidance diet is the only prophylactic approach to the treatment of food allergies (Taylor et al., 1986a; Taylor et al., 1999).
For example, individuals allergic to peanuts must simply avoid ingesting peanuts. The construction of safe and effective avoidance diets is often a challenge for individuals with food allergies. With packaged foods, these individuals must spend considerable time in the scrutiny of ingredient declarations on product labels. They must be taught to recognize the numerous terms that may signify the presence of food components or ingredients derived from their offending food(s). Some foods, especially in foodservice settings, are sold without ingredient statements.
Clearly, the allergic consumer can encounter numerous hazardous situations in such circumstances and must be trained to be extremely vigilant. Also, exposure to extremely little amounts of the offending food may be sufficient to elicit allergic reactions in some sensitive individuals, further complicating the necessary vigilance in the implementation of effective avoidance diets.
Threshold Doses for Allergenic Foods. As noted, individuals with IgE-mediated food allergies will experience symptoms on exposure to little amounts of the offending food. The interaction of a little quantity of the allergen with specific IgE antibodies on the surface of the mast cell or basophil membrane triggers the release of massive quantities of mediators, which accounts for the low degree of threshold.
The precise threshold doses for allergenic foods own not been carefully investigated and are likely to be variable from one allergic individual to another.
In a recent study, Hourihane et al. (1997b) demonstrated that a group of individuals with peanut allergy displayed diverse thresholds for peanuts. The most sensitive individual among 12 tested subjects experienced an objective reaction when exposed to 2 mg of peanut protein. Other patients in the group did not even reply to the highest dose used in the challenge trial which was 50 mg of peanut protein. While this experiment clearly demonstrates that the threshold level is not zero, the threshold dose is fairly low. Whether other allergenic foods own thresholds as low as those for peanuts remains to be determined.
Allergenicity of Foods Produced Through Agricultural Biotechnology.
In the genetic modification of foods, genes are transferred from one organism to another. Because these genes code for the expression of a specific protein, novel proteins are expressed in the transgenic variety as a result. Because every allergens are proteins, the theoretical possibility exists that these novel proteins might be allergenic or that they might become allergenic. However, only a few of the numerous proteins found in nature are allergenic, so the probability of the transfer of an allergen is rather low. The potential allergenicity of the novel proteins expressed in the new varieties produced through agricultural biotechnology should be assessed in every case.
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The potential allergenicity of the novel proteins in transgenic varieties can be assessed (FAO/WHO, 2001; Metcalfe et al., 1996; Taylor and Hefle, 2001a).
If a gene is transferred from a known allergenic source, the potential allergenicity of the expressed novel protein can be assessed with reasonable certainty by evaluating its reactivity by specific serum screening with serum containing IgE antibodies from individuals with well documented allergies to the source material. This assessment approach was demonstrated to be effective when it was sure that a Brazil nut protein transferred into soybeans to correct the inherent methionine deficiency of soybeans was the heretofore unidentified major allergen from Brazil nuts (Nordlee et al., 1996). The company involved abandoned further commercial interest in these transgenic soybeans as a result.
It should be emphasized that genes are not often obtained from known allergenic sources in the development of commercial transgenic varieties. However, when genes are transferred from known allergenic sources, it must be assumed that the gene encodes for an allergenic protein unless proven otherwise.
More typically, genes are obtained from sources with no history of allergenicity. In these situations, a decision-tree approach is advocated for the assessment of the potential allergenicity of the novel protein. While no single test can perfectly predict the potential allergenicity of a specific novel protein from a source with no history of allergenicity, the application of a series of tests provides reasonable assurance that the novel protein is not likely to become an allergen.
Several decision-tree approaches own been developed (FAO/WHO, 2001; Metcalfe et al., 1996; Taylor and Hefle, 2001a). These approaches rely upon evaluation of the source of the gene and its history of allergenicity, the sequence homology of the novel protein to known allergens, the immunoreactivity of the novel protein with serum IgE from individuals with known allergies to the source of the transferred gene, the immunoreactivity of the serum IgE from individuals with known allergies to sources that are broadly related to the source of the novel gene (e.g., grass pollen allergic individuals in cases where the gene is obtained from monocot sources), the pepsin resistance or digestive stability of the novel protein, and the immunogenicity of the novel protein in validated animal models (Fig.
3). Other factors especially the level of expression of the novel protein in the food are also likely to be significant since allergies are generally elicited by food proteins where dietary exposure is comparatively high.
Foods produced through agricultural biotechnology including corn, soybeans, canola, and potatoes are already reaching the consumer marketplace. The potential allergenicity of the novel proteins expressed in these commercial products has been assessed using the approaches indicated above. The novel proteins in these approved transgenic varieties are not obtained from known allergenic sources, are not structurally homologous to known food or environmental allergens, and are sensitive to digestive proteolysis.
Furthermore, the novel proteins are expressed at extremely low levels in the edible portions of these modified crops. Thus, the likelihood of allergenicity from this current generation of crops produced by agricultural biotechnology is virtually nil.
Considerable publicity has surrounded one specific transgenic variety, the so-called StarLink™ corn. StarLink corn was never approved for human use, but was unfortunately approved for animal feed use. When segregation failed, some StarLink corn residues were found in corn-based food products intended for human consumption. Although the gene inserted in StarLink corn was obtained from a source with no history of allergenicity and the novel protein was not structurally similar to known food or environmental allergens, the novel protein was comparatively more resistant to digestive proteolysis than other novel proteins that had been approved for other genetically modified crops.
For this reason, StarLink corn was never approved for human consumption. However, given the extremely low level of exposure to the novel protein in StarLink corn in corn-based food products, the likelihood of allergic sensitization to this specific novel protein is low. Despite that and due to the concerns about the potential allergenicity of this transgenic variety, it has been withdrawn from the marketplace, although traces may remain for one or more growing seasons. This episode emphasizes the importance of assessing the potential allergenicity of transgenic varieties as part of the overall safety evaluation process.
Agricultural biotechnology can also be used to decrease the inherent allergenicity of foods.
The proteins in specific foods that are responsible for allergic reactions could be removed or altered through agricultural biotechnology. While no commercial examples exist yet of the application of this possibility, it is an athletic area of research with peanuts.
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Non-IgE Cell-Mediated Reactions
As noted earlier, cell-mediated allergic reactions, also known as delayed hypersensitivity reactions, own an onset time of 6–24 hours after ingestion of the offending food.
The reactions develop slowly, reaching a peak at approximately 48 hours and then slowly subsiding over 72–96 hours. Cell-mediated food allergies involve the interaction between specific antigens or allergens from the food and sensitized, tissue-bound T cells that release inflammatory mediators when sensitized (Sampson, 1991). The role of cell-mediated reactions in food allergies remains somewhat uncertain. Compelling and mounting evidence has accumulated, however, indicating that celiac disease occurs through a T cell-mediated mechanism (Ferguson, 1997; Strober, 1986).
Also known as celiac sprue or gluten-sensitive enteropathy, celiac disease is a malabsorption syndrome occurring in sensitive individuals upon the consumption of wheat, rye, barley, triticale, spelt, and kamut (Ferguson, 1997; Lemke and Taylor, 1994 ). The role of oats in celiac disease has recently been questioned. Apparently, oats and oat products that are totally free of wheat, rye, and barley, are safe for celiac sufferers to consume (Janatuinen et al., 1995).
After consumption of the offending grains or products made from these grains, the absorptive epithelial cells in the little intestine are damaged by an inflammatory process (Ferguson, 1997). As a result, absorption of nutrients through the epithelium is compromised. The loss of absorptive function along with the ongoing inflammatory process results in a severe malabsorption syndrome characterized by diarrhea, bloating, weight loss, anemia, bone pain, chronic fatigue, weakness, muscle cramps, and, in children, failure to acquire weight and growth retardation (Lemke and Taylor, 1994; Skerritt et al., 1990).
A part of wheat, the gliadin part, and related part in barley and rye are associated with initiation of celiac disease in susceptible individuals (Skerritt et al., 1990).
Celiac disease is an inherited trait, but the inheritance is complicated and poorly understood. Celiac disease occurs in about 1 of every 3000 individuals in the U.S. (Kasarda, 1978). In some other parts of the world, celiac disease occurs more frequently. The highest prevalence occurs among individuals in certain regions of Europe (Greco et al., 1992; Kasarda, 1978). Celiac disease seems to happen more frequently among Europeans than among Americans of European descent for unexplained reasons.
Celiac disease rarely occurs among individuals of Chinese or African descent (Ferguson, 1997).
The treatment of celiac disease involves the avoidance of wheat, rye, barley, triticale, spelt, kamut, and oats and products of these grains (Hartsook, 1984). The threshold dose of gliadin and related protein fractions needed to provoke celiac disease in sensitive individuals is not precisely known, but symptoms can be elicited by ingestion of little amounts of these grains (Lemke and Taylor, 1994).
If a gluten-free diet is followed, the symptoms of celiac disease will resolve and the absorptive function of the little intestine will be restored. Most celiac sufferers adhere to extremely strict gluten-free diets. In the absence of information on the safety of products made from the offending grains, affected individuals often select to avoid products that contain remarkably little amounts of protein from these sources including rye alcohol, wheat starch, malt extract, and vinegar. The wisdom of such severely restricted avoidance diets remains to be established.
In contrast to true food allergies, food intolerances happen through non-immunological mechanisms.
However, love true food allergies, food intolerances affect some individuals in the population but not every. Individuals suffering from food intolerances can generally tolerate little amounts of the offending food or food ingredient in their diet without ill effects. Food intolerances can be divided into three categories: anaphylactoid reactions, metabolic food disorders, and idiosyncratic illnesses.
Anaphylactoid Reactions. In IgE-mediated food allergies, the release of histamine and other mediators from the mast cells and basophils is mediated by the interaction of IgE with proteinaceous allergens, as described earlier. In contrast, anaphylactoid reactions are caused by substances that bring about the release of the same mediators from mast cells without the involvement of IgE (Lemke and Taylor, 1994).
Some substance in the implicated food is presumed to destabilize the mast cell membranes allowing for the spontaneous release of histamine and the other mediators. However, no such histamine-releasing substance has ever been isolated or identified in foods, although this mechanism is well established with certain drugs. Strawberry sensitivity is generally cited as the best example of an anaphylactoid reaction. Although strawberries are known to cause adverse reactions (frequently urticaria) in susceptible individuals, there is little evidence for the existence of an IgE-mediated mechanism. Strawberries contain little protein, and no evidence has been found for the existence of a strawberry allergen.
Furthermore, there is no evidence for the existence of strawberry-specific IgE in the sera of strawberry-sensitive individuals. Spontaneous histamine release is thus a plausible mechanism. However, if a substance exists in strawberries that destabilizes mast cell membranes, that substance has yet to be identified. The possibility that strawberry sensitivity is a form of oral allergy syndrome has not yet been excluded, and is an equally plausible mechanism.
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Metabolic Food Disorders.
Metabolic food disorders result either from inherited defects in the ability to metabolize some component of food or from a genetically sure, enhanced sensitivity to some foodborne chemical that occurs through an altered metabolic pattern (Lemke and Taylor, 1994). Lactose intolerance is an example of an illness that occurs when a genetic deficiency affects the host’s ability to metabolize a food component (Kocian, 1988). In lactose intolerance, an inherited deficiency occurs in the quantity of the enzyme, β-galactosidase, leading to an impaired ability to digest lactose. Favism is an example of a genetic deficiency that enhances the sensitivity to a foodborne chemical.
In favism, a genetic deficiency in glucose-6-phosphate dehydrogenase in the erythrocyte results in an enhanced sensitivity to several hemolytic substances that happen naturally in fava beans (Mager et al., 1980). These two metabolic food disorders are the most common and best understood illnesses in this category of food intolerances.
Lactose Intolerance. Lactose is a dissaccharide and the principal sugar in milk. Normally, lactose is hydrolyzed into its constituent monosaccharides, galactose and glucose, in the little intestinal mucosa. These monosaccharides can then be absorbed and used as metabolic sources of energy.
In lactose intolerance, the activity levels of β-galactosidase, the key hydrolytic enzyme that exists in the mucosal membranes of the little intestine, are diminished (Houts, 1988; Suarez and Savaiano, 1997). Since lactose cannot be absorbed in the little intestine unless it is hydrolyzed to glucose and galactose, the undigested lactose passes into the colon where it encounters large populations of bacteria. The colonic bacteria metabolize the lactose to CO2, H2, and H2O (Lemke and Taylor, 1994).
Abdominal cramping, flatulence, and frothy diarrhea are the predominant symptoms of lactose intolerance (Bayless et al., 1975) and are the direct result of the action of the colonic bacteria on lactose. The symptoms vary in intensity in concert with the individual level of activity of β-galactosidase in the little intestine and the quantity of lactose ingested.
Lactose intolerance is a fairly common metabolic food disorder. Lactose intolerance is especially prevalent among some ethnic groups in the world including Greeks, Arabs, Jews, black Americans, Hispanics, Japanese, and other Asians (Houts, 1988; Suarez and Savaiano, 1997).
Only about 6-12% of Caucasians are affected (Suarez and Savaiano, 1997). Lactose intolerance can own its onset at any age, occurring as early as the age of three (Simoons, 1980). However, lactose intolerance tends to worsen with advancing age and is often more common and more severe among the elderly (Houts, 1988; Simoons, 1980). The level of intestinal b-galactosidase is generally sufficient at birth to permit digestion of lactose in mother’s milk, but susceptible individuals suffer as a result of decreased activity of this enzyme as life progresses. Lactose intolerance may also happen on a more transitory basis on occasion, secondary to another intestinal illness or infection such as a bout of viral gastroenteritis (Metcalfe, 1984b).
Secondary lactose intolerance tends to subside rather quickly after the original illness is resolved.
Individuals with lactose intolerance are capable to control their symptoms through the avoidance of dairy products containing lactose (Lemke and Taylor, 1994). However, numerous lactose-intolerant individuals can tolerate some lactose in their diets. The degree of tolerance for lactose is individualistic and variable among such individuals. Yogurt, sour cream, and acidophilus milk that contain athletic cultures of bacteria with b-galactosidase activity, are better tolerated by lactose-intolerant individuals than other dairy products (Kolars et al., 1984).
Lactose-hydrolyzed milk is also available in the marketplace (Paige et al., 1975). And, lactose-intolerant individuals can add b-galactosidase to milk just before consumption, and this seems to be an effective practice (Barillas and Solomons, 1987). Certainly, the level of tolerance for dairy products is much higher with lactose intolerance than it is with IgE-mediated cows’ milk allergy (Taylor, 1990).
Favism. Individuals with an inherited deficiency of the enzyme, glucose-6- phosphate dehydrogenase (G6PDH), in their erythrocytes are susceptible to favism.
Symptoms happen after consumption of fava beans or the inhalation of pollen from the Vicia faba plant (Mager et al., 1980). Fava beans contain vicine and convicine, naturally occurring oxidants that are capable to damage the erythrocyte membranes of G6PDH-deficient individuals causing hemolysis and the symptoms of hemolytic anemia (Marquardt, 1989). G6PDH is a critical enzyme in erythrocytes because it helps to maintain adequate levels of the reduced form of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH).
GSH and NADPH assist to avert oxidative damage to erythrocytes. In individuals who are G6PDH-deficient, this protective mechanism is nonfunctional and the oxidants in fava beans can exert their hemolytic effects. In rare cases with repeated exposure, more severe symptoms can happen including hemoglobinuria, jaundice, and renal failure. The onset time after ingestion of the fava beans ranges from 5 to 24 hours. The illness is self-limited, however, with symptoms resolving promptly and spontaneously upon avoidance of further exposure.
G6PDH deficiency is extremely common and affects approximately 100 million individuals on a worldwide basis (Mager et al., 1980).
The prevalence is highest among Oriental Jewish groups in Israel, Sardinians, Cypriot Greeks, African Americans, and certain African populations. This inherited trait is virtually absent among Caucasians, North American Indians, and Eskimos. Despite the high prevalence of G6PDH deficiency, favism is an unusual occurrence because fava beans are not frequently eaten except in Mediterranean and Middle Eastern locales.
Some individualistic adverse reactions to foods are idiosyncratic in that the mechanism for these illnesses is unknown.
Numerous reports, mostly anecdotal, own occurred regarding illnesses in certain individuals attributed to certain specific foods or food ingredients. Conceivably, a large number of diverse mechanisms could be involved in these idiosyncratic reactions. The symptoms involved in idiosyncratic reactions range from unimportant to severe, life-threatening reactions (Taylor et al., 1989b).
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The role of specific foods or food ingredients in the causation of these idiosyncratic reactions remains to be sure in numerous cases.
The cause-and-effect relationships can only be established through carefully controlled DBPCFCs (Taylor et al., 1989b). A positive DBPCFC would definitely confirm that the specific food or food ingredient is involved in the specific adverse reaction. The mechanism of the adverse reaction, however, cannot be sure from the positive DBPCFC alone. A negative DBPCFC indicates either that foods are not involved in causation of the reaction or at least that the specific food or food ingredient used in the challenge was wrongly incriminated. Unfortunately, DBPCFCs are rarely performed to establish convincingly that a specific food or food ingredient is associated with a specific idiosyncratic reaction.
The role of specific foods or food ingredients are firmly established in a few of the numerous alleged foodborne idiosyncratic reactions.
Sulfite-induced asthma is perhaps the best example (Bush and Taylor, 1998). In the case of sulfite-induced asthma, numerous clinicians own documented the role of sulfites in the provocation of asthma in dozens of patients using DBPCFC protocols (Bush and Taylor, 1998). Aspartame has been identified as a causative factor in two subjects using DBPCFC (Kulczycki, 1986). However, other cases of aspartame-induced urticaria own not been identified so this may be a rather rare phenomenon.
For numerous other alleged idiosyncratic reactions to specific foods or food ingredients, the association with the specific food or food ingredient has not been conclusively documented through DBPCFCs.
Examples would include the role of chocolate or aspartame in migraine headache; the roles of BHA, BHT, tartrazine, benzoates, or parabens in chronic urticaria; the role of tartrazine in asthma; the role of monosodium glutamate (MSG) in asthma or MSG Symptom Complex; and the role of sugar in aggressive behavior (Bush and Taylor, 1998). A thorough critique of the numerous studies that own been conducted on the role of these foods or food ingredients in the causation of these idiosyncratic reactions is beyond the scope of this specific review.
However, extremely few of the clinical studies own used double-blind and placebo-controlled trial designs. Furthermore, numerous of the studies own involved individuals with chronic, episodic symptoms such as chronic urticaria or asthma and the clinical investigators own removed critical medications from the patients before initiating the challenge trials. In such cases, the observed symptoms might be due either to the challenge substance or to the withdrawal of medications that controlled the condition. With such critical clinical design flaws, the role of these specific foods and food ingredients in these specific idiosyncratic illnesses remains unproven. Furthermore, psychological disorders may be involved in perceived reactions to specific foods or food ingredients (King, 1984; Selner and Staudenmayer, 1997).
In a few cases, the role of specific foods or food ingredients in idiosyncratic reactions has been disproven by careful clinical investigations.
However, consumers may persist in their belief that such reactions happen. The outstanding example of such a reaction is the role of artificial food colors in hyperkinetic behavior in children. Several decades ago, Dr. Benjamin Feingold implicated artificial food colorants as causative factors in hyperkinesis on the basis of poorly controlled trials and anecdotal experiences (Feingold, 1975). The resulting publicity on the Feingold hypothesis was considerable, and, consequently, numerous consumers became convinced of a relationship between ingestion of artificial food colorants and provocation of hyperkinetic behavior in children.
Subsequently, several double-blind, placebo-controlled challenge trials own been conducted with artificial food colorants and own demonstrated convincingly that few, if any, hyperkinetic children are adversely affected by the ingestion of these food colorants (Harley et al., 1978a). Despite this evidence, numerous consumers persist in their belief regarding the role of artificial food colorants in hyperkinetic behavior.
A similar situation exists with honor to monosodium glutamate where the involvement of MSG intake in the so called Chinese Restaurant Syndrome, now more appropriately called MSG Symptom Complicated, has been alleged so often that it is now accepted as fact by numerous consumers.
However, the role of MSG in MSG Symptom Complicated has not been corroborated in carefully controlled clinical challenge studies (Kenny, 1986; Tarasoff and Kelly, 1993). More recently, MSG intake has been linked to asthma (Allen et al., 1987). However, the role of MSG in provocation of asthma seems questionable at best when patients are evaluated using a DBPCFC protocol (Bush and Taylor, 1998). The alleged role of tartrazine, also known as FD&C Yellow #5, in asthma and chronic urticaria is also extremely questionable in the light of DBPCFCs (Bush and Taylor, 1998; Stevenson et al., 1986).
Yet, undeclared tartrazine remains the basis for a large number of FDA recalls.
Sulfite-Induced Asthma. Sulfiting agents allowed for use in foods include sulfur dioxide, potassium metabisulfite, sodium metabisulfite, potassium bisulfite, sodium bisulfite, and sodium sulfite. Sulfiting agents own been used as food ingredients for numerous years, because they own numerous significant technological benefits (Taylor et al., 1986b). Sulfites also happen naturally in some foods, especially fermented foods (Taylor et al., 1986b).
However, residual levels of sulfites in foods vary from a few ppm arising mostly from natural sources, to less than 10 ppm to >1,000 ppm as a result of additive usage.
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Although sulfites own been used for centuries, they own been implicated as triggers of asthma in some sensitive individuals only in recent years (Bush and Taylor, 1998; Stevenson and Simon, 1981). The reactions generally happen within a few minutes after the ingestion of a provoking dose of sulfite. The reactions can be fairly severe on occasion and deaths own been attributed to sulfite-induced asthma (Bush and Taylor, 1998).
The role of sulfites in the causation of asthma in susceptible individuals has been well documented by DBPCFC (Bush and Taylor, 1998; Stevenson and Simon, 1981). Other symptoms own also been alleged to happen as a result of sulfite sensitivity but these reports own been largely anecdotal and unverified by DBPCFC (Bush and Taylor, 1998).
Sulfite-induced asthma affects only a little percentage of every asthmatic individuals (Bush et al., 1986). The prevalence among severe asthmatics who are dependent upon steroid-based drugs for control of their symptoms appears to be in the range of 4–7%, while mild asthmatics do not seem to be extremely susceptible to sulfite ingestion (Bush et al., 1986).
Thus, the overall prevalence of sulfite-induced asthma is estimated at 1.0–1.5% of the entire asthmatic population (Bush et al., 1986).
Sulfite-induced asthmatics display thresholds for sulfites (Bush and Taylor, 1998; Taylor et al., 1988). While the ingestion of high doses of sulfite in highly sulfited foods and beverages can be fairly hazardous for susceptible individuals, the ingestion of sulfited foods with lower levels of residual sulfite (<100 ppm as entire SO2) seems to present little risk (Taylor et al., 1988). Thus, sulfite-sensitive asthmatics must be alert to the presence of sulfites in foods at levels that are required to be declared on the ingredient statement, but are at no risk from ingestion of sulfites from foods that own levels of residual sulfite under the detection limit of current assay procedures (<10 ppm as entire SO2).
The mechanism of sulfite-induced asthma is not known.
Several diverse mechanisms own been proposed including IgE-mediated reactions, hypersensitivity to inhaled SO2 from ingestion of acidic foods and beverages, and sulfite oxidase deficiency (Bush and Taylor, 1998). However, none of these mechanisms has been proven, so sulfite-induced asthma remains an idiosyncratic illness.
Implications for Food Manufacturing
Colonization with the Staphylococcus aureus bacterium was significantly and independently associated with food allergy in young children with eczema enrolled in a pivotal peanut allergy prevention study.
S.aureus is a marker for severe eczema, and early eczema is a widely recognized risk factor for developing food allergies in young children.
But the findings from the Learning Early About Peanut Allergy (LEAP) study cohort show that even after controlling for eczema severity, skin S.
aureus positivity was associated with an increased risk for developing allergies to peanuts, eggs, and cow’s milk.
S. aureus colonization was also associated with persistent egg allergy until at least age 5 or 6 years in the LEAP cohort analysis in the Journal of Allergy and Clinical Immunology.
The lead researcher, Olympia Tsilochristou, MD, of Kings College London, said in a press statement that the findings could assist explain why young children with eczema own a extremely high risk for developing food allergies.
While the exact mechanisms linking the two are not known, «our results propose that the bacteria Staphylococcus aureus could be an significant factor contributing to this outcome,» she said.
The findings also propose that S. aureus colonization may inhibit peanut tolerance among at-risk infants when peanuts are introduced extremely early in life.
Among the nine participants in the peanut-consumption arm of the study (i.e., no peanut allergy at baseline) who had confirmed peanut allergy at 60 and 72 months, every but one were colonized with S. aureus at one or more LEAP study visits.
«The fact that S. aureus was associated with greater risk of peanut allergy among peanut consumers but not peanut avoiders further suggests that peanut consumption was less effective in the prevention of peanut allergy among participants with S.
aureus compared with those with no S. aureus,» the researchers wrote.
The LEAP study enrolled infants ages 4-11 months with severe eczema, egg allergy, or both. The babies were randomized to therapeutic peanut consumption or peanut avoidance, and every had eczema clinical evaluation and culture of skin and nasal swabs at baseline.
The follow-up LEAP-On study assessed the children at age 72 months, after 12 months of peanut avoidance in both groups.
Skin and nasal swabs were obtained at baseline and at age 12, 30, and 60 months.
A entire of 48.8% of the participants had some form of S. aureus colonization (32.2% skin and 32.3% nasal) on at least one LEAP study visit, with most having just one positive test result. The greatest rates of colonization were recorded at 4-11 months of age.
S. aureus colonization was significantly associated with eczema severity, along with hen’s egg white and peanut specific immunoglobulin (sIg)E production at any LEAP visit.
But even after controlling for eczema severity, hen’s egg white and peanut sIgE levels at each LEAP and LEAP-On visit were significantly associated with skin S. aureus positivity, the team noted.
«This relationship was even stronger when we looked into high-level hen’s egg white and peanut sIgE production,» the researchers wrote. «Similar findings were noted for cow’s milk, where high-level sIgE production to milk at 30, 60, and 72 months of age was related to any skin S.
aureus colonization. Together, these data propose that S. aureus is associated with hen’s egg, peanut, and cow’s milk allergy.»
In the LEAP study, extremely early peanut consumption was found to reduce the risk of peanut allergy at 60 months in infants at high risk for developing the allergy, but infants in the consumption arm of the study with S. aureus colonization were approximately seven and four times more likely to own confirmed peanut allergy at 60 and 72 months, the team said.
Study strengths, Tsilochristou and co-authors noted, included the rigorous design; a limitation was the reliance on bacteriological culture to identify S.
aureus colonization rather than using DNA-based testing.
«S. aureus has been implicated in the development and severity of atopic diseases, namely eczema, allergic rhinitis, and asthma; our findings extend these observations to the development of food allergy independent of eczema severity,» the investigators concluded.
«The role of S. aureus as a potential environmental factor should be considered in future interventions aimed at inducing and maintaining tolerance to food allergens in eczematous infants.
Further prospective longitudinal studies measuring S. aureus with more advanced techniques and interventional studies eradicating S. aureus in early infancy will assist elucidate its role in the development of eczema or food allergy,» the team wrote.
Millions of people live with food allergies and the guessing game that comes with diagnosing them and avoiding the foods that trigger a reaction.
It’s a well-documented struggle for adults who are capable to communicate their symptoms and track their reactions to certain foods. But, it can be an exponentially more hard road when parents are relying on a kid to attempt and verbalize reactions that can’t be seen, such as respiratory difficulties and gastrointestinal issues.
One of more than 300 conditions that put children at a higher risk for pediatric feeding disorder, food allergies can often be misconstrued as an intolerance to a certain food, general pickiness or other chronic conditions by those who don’t fully understand the gravity of the condition.
That’s part of the reason why Feeding Matters so appreciates Food Allergy Awareness Week, recognized May 12-18. It allows for an chance to educate the public and it offers a space for conversations, tolerance and understanding.
An estimated 6 million children are living with food allergies in the U.S., according to the Food Allergy and Anaphylaxis Connection Team (FAACT). And, only eight foods are responsible for 90% of every food allergies, according to FAACT. Statistics reported by the Journal for the American Medical Association indicate that shellfish, milk and peanuts are the top-three most common culprits of food allergies, followed by tree nuts, fin fish, eggs, wheat, soy and sesame.
Someone who lives with a food allergy can suffer a number of reactions, ranging from a rash to severe respiratory distress.
In fact, experts estimate that a food allergy sends someone to an emergency room once every three minutes. And, the situation seems to be escalating in recent years.
Anaphylactic reactions own increased almost 400 percent over a 10-year period between 2007 and 2016, and about 40 percent of children living with food allergies experience a severe and sometimes anaphylactic reaction, according to Food Allergy Research and Education (FARE).
Those who are forced to navigate life with a food allergy are also required to maintain a beautiful consistent state of vigilance.
That’s one of the reasons that schools put restrictions on the types of treats that can enter a classroom, and why some airlines own stopped serving peanuts as mid-flight snacks.
Knowing that trace amounts of an ingredient or cross-contamination could trigger a reaction, most people living with food allergies are advised to avoid buffets and deli stations, bakeries, ethnic restaurants because of potential language barriers, and Asian cuisine due to its liberal use of peanut-based foods and oils.
It is, however, possible to eat out with a food allergy.
As awareness of the condition improves, so too does general tolerance for it and those who live with it. Restaurants are increasingly providing allergy information on their menus, and relationships with servers and restaurant owners make those conversations easier to have.
For more information about food allergies, we urge you to visit these resources:
Food Allergy and Anaphylaxis Connection Team
Food Allergy Research and Education
Kids With Food Allergies
When you head out to a restaurant, you expect to own a nice meal. Unfortunately, what’s meant to be a memorable experience can turn into a problem if you own an adverse reaction to a food allergy.
A food allergy from a restaurant can range from minor to severe.
If you’re injured because of a bad reaction at a restaurant, you may deserve financial compensation. Here’s what you need to know from our Las Vegas personal injury attorney firm.
Types of Restaurant Liability for Allergens
Here are just some of the ways that a restaurant may be liable for food allergens:
- Incorrectly informing customers about ingredients in their products
- Giving incorrect information when customers enquire questions about allergens
- Failing to protect consumers and inform them about common allergies love peanuts
- Cross-contamination and accidental allergic reactions
- Responding inappropriately when a person has an adverse reaction
Any way that a restaurant doesn’t take sufficient care for the well being of their customers can be grounds for legal liability.
Because the restaurant is a for-profit trade, the obligation of the restaurant to take sufficient care for their customers is extremely high.
If I am allergic to a food, will my kid be allergic, too?
If a parent or sibling is allergic to a food, your kid may be more likely to develop an allergy. However, you may increase the chances of preventing a food allergy if you eliminate the offending food from your toddler’s diet.
How prevalent are food allergies?
True food allergies are fairly rare.
However, about one-third of children may own an adverse reaction to a food, which may be mistaken for a food allergy.
What are the most common food allergies and food intolerances?
The food allergies most common among young children are those to cow’s milk, soy, egg whites, wheat, and citrus. Any food has the potential to trigger an allergy, though.
Lactose intolerance and gluten intolerance are 2 of the most common types of food intolerances. Children can also own intolerance to food additives, such as monosodium glutamate, nitrates, nitrites, sulphites, and dyes.
What is a food allergy?
Food allergies happen when the body’s immune system reacts to a protein in a specific food.
When exposed to the food, the body produces antibodies to the protein. Once enough antibodies build up, an exposure to the food will trigger allergic symptoms.
Will my kid own her food allergy or intolerance for life?
It depends. About half of every children who develop a food allergy before age 3 eventually outgrow it, generally by about age 7 years.
Children who develop an allergy after age 3 years are less likely to outgrow it.
Allergies to nuts and shellfish are more likely to persist for life.
Also, intolerances such as wheat sensitivity in celiac disease are lifelong conditions.
How dangerous is a food allergy?
Allergic reactions can be serious. Seek medical assistance immediately if your child
- Develops swelling in the head and neck
- Has bloody diarrhoea
- Has generalized hives (smooth red swellings that itch, burn, or sting)
- Has trouble breathing or turns blue
- Is extremely pale or weak
Even if your kid does not show any of these severe symptoms, you should consult your health care professional soon if you suspect that your kid has an allergy.
What is food intolerance?
Food intolerance is an abnormal but non-allergic reaction to a food.
With food intolerance, a person generally does not make enough of a certain enzyme needed to digest some part of a food.
What are the symptoms of a food allergy?
Diarrhoea and vomiting are the most common symptoms. Skin rashes, itching, runny nose, wheezing, tightness in the throat, and swelling of the lips, tongue, or mouth may also occur.
Symptoms may appear within a few minutes or take as endless as 48 hours to appear.
As a general law, if symptoms are triggered by an allergy, your kid won’t own a fever.
What is the difference between an adverse reaction to a food and a true food allergy?
With a food allergy, the body’s immune system mistakenly tries to defend against certain food proteins as if they were invading germs.
With an adverse reaction to a food, although symptoms may be similar to those of an allergy, the immune system is not involved.
In either case, it is generally recommended that the problem food be eliminated from the diet.
Can food allergies be prevented?
Delaying the introduction of highly allergenic foods may assist.
If a kid has a family history of allergies, it is best not to introduce cow’s milk, soy, wheat, corn, and citrus until after the first birthday.
How is an allergy diagnosed?
Generally, the suspect food is eliminated from the diet for 2 weeks to see if symptoms lessen.
If the cause of symptoms is not clear, skin or blood tests may be performed.
How can I tell whether my kid had outgrown her food allergy?
If you desire to test, a food challenge should only be performed under your doctor’s supervision in his office. Never attempt a food challenge yourself at home.
Can You Sue a Restaurant for Food Allergy?
Yes, you can sue a restaurant for food allergy.
There are several ways that a restaurant may breach their duty of care towards a restaurant patron when it comes to allergies. In every cases, if the restaurant could own prevented the harm by being more careful, the victim may recover for their damages. The victim has to prove that they’re hurt because of allergies at the restaurant.