Allergy FAQs

What are food allergies?
Food allergies are reactions to otherwise harmless foods or food ingredients that involve the body's immune system (known as “IgE mediated”). Usually following accidental ingestion (eating the food or something containing it as an ingredient), a reaction rapidly occurs when the immune system responds abnormally to the protein or proteins in the food.

Virtually any food can cause an allergic reaction in a susceptible individual. The most common childhood allergens are cow's milk, egg, peanut, soy, wheat, tree nuts, fish and shellfish. In adults, the most common allergens are peanut, tree nuts, fish, and shellfish.

In an allergic reaction, histamines and other chemicals flood the body to fight off a perceived invader. Their effect produces the symptoms that the allergic individual experiences, which may range from mild discomfort to life threatening. The most serious reactions are termed “anaphylaxis”.

Commonly seen signs of an acute food allergic reaction are flushing, hives, edema (swelling face, lips), bronchoconstriction (throat constriction, difficulty breathing), abdominal cramping, vomiting, hypotension (drop in blood pressure), and dysrhythmias (irregular heartbeat).

Reactions to food or food ingredients that do not involve the immune system are not food allergies. Non-immunologic reactions are termed food intolerance or sensitivities. There is much confusion around these different terms.

How are food allergies diagnosed?
Diagnosing a food allergy may not be difficult if a person always has the same reaction after eating a certain food. But foods are generally not eaten in isolation and it can be difficult to track down and identify the cause of the adverse reaction. A thorough clinical picture is essential, which means taking a detailed medical and dietary history, keeping a food diary, eliminating suspect foods, conducting skin tests, and evaluating food challenges.

The skills of the clinician making the diagnosis are a key element in its accuracy. The advice of an expert food allergy organization should always be sought about reliable investigation, diagnosis and treatment.

How common are food allergies?
Little reliable clinical data exists about the numbers of people who have genuine food allergies in different parts of the world. Estimates vary considerably, from virtually none in much of Asia, Africa, Southern and Eastern Europe, to fairly common in others. North America and North-Western Europe are reported to have much larger numbers of food allergic - and specifically peanut allergic - individuals. Strong debate exists over the reasons for rising levels of food allergy reported in these areas.

Who is most likely to develop food allergies?
Foods do not cause allergies. Some common foods may act as triggers for allergic reactions in some individuals, particularly younger children. The immune systems of these individuals cause adverse reactions to one or more common foods containing allergens to which they are sensitive. When they encounter these foods, almost always when unaware that something they are eating contains them, the symptoms they quickly experience show that they have a food allergy.

Children with atopic disorders such as asthma or eczema or with existing allergies to foods such as milk or egg are more likely to be allergic to peanut proteins and to proteins in other nuts and other foods.

What are the most common food allergens?
“Food allergens” are natural components of foods to which some people are allergic. The allergens are almost always proteins. Common high protein foods are therefore associated with food allergy. Official lists of these foods vary around the world, but generally include milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, soy and sometimes sesame, lupin and kiwi. [Peanuts, while botanically a legume, are generally considered to be a nut.] Individuals should always consult a food allergy expert body to find out which foods are required to be labelled as allergens where they are.

What are the usual symptoms of food allergies?
Most food allergic individuals experience mild reactions when they unexpectedly encounter a trigger food. The range of severity of symptoms, however, is very wide: degrees of hives (urticaria), swelling of the face, constriction of the throat, difficulty breathing, cramping and vomiting. A small proportion may experience severe and potentially fatal anaphylactic shock (generally called “anaphylaxis”).

Anaphylaxis is the life-threatening reaction induced by any severe allergy, not just to food. It can be caused by foods, insect stings and medications. It can constrict the airways in the lungs, severely lower blood pressure, and swell the tongue or throat, among other symptoms. Anaphylaxis is rare, but can be fatal if not treated immediately.

Are food allergies life long?
Children commonly “outgrow” early life allergies to foods such as eggs and milk. Allergies to peanuts, nuts, fish and shellfish generally last much longer, including for life.

About 1 in 5 children with peanut allergy become free of it as they get older, but this is not predictable and should never be a reason to be lax in avoiding potential trigger foods. Food allergy commencing in an adult tends to persist for life.

Why are peanut allergies common and sometimes severe?
Peanut allergies are common in some parts of the world primarily because peanuts are so widely consumed and used as food ingredients and exposure to peanut protein in the environment is high. That should not stigmatise peanuts as they are a wholesome food for the vast majority of people. Sesame is a more potent allergen than peanut, but because it is not nearly so widely encountered, it is much lower down the list of common allergens.

Peanuts are a complex plant food, with more than 30 different proteins. Research is underway to identify exactly which proteins trigger an allergic reaction, and why the reaction can vary in severity between individuals.

Peanut allergens are not broken down or neutralised by processing or cooking and so remain potent in products containing peanuts.

Are the number of people with peanut allergies increasing?
Reported cases of food allergy are rising in North America and some European countries. From 1997 to 2007, the prevalence of reported food allergy in the United States increased 18% in children under the age of 18 years. Reported peanut allergy tripled in children under the age of 18 years in a similar time frame, from 0.4% in 1997 to 1.4% in 2008. It is estimated that peanut allergy now affects 0.6% of the US population.

Research indicates that all allergies, not just to food, are increasing. It is difficult to determine, however, if the increased reports of food allergies in general and peanut allergy in particular are due more to actual increases in incidence or reflect increased awareness among consumers and health professionals. It is likely a combination of the two. Self-reporting studies are the basis for the current high American prevalence figures and these are inherently biased to over reporting.

The picture is not clear cut in any country. The evidence from double-blind, placebo-controlled food challenges, the gold standard for diagnosing food allergy, points to over-diagnosis of peanut allergy, especially in children, over the past decade. This may stem from many more non-specialists entering the allergy field and the widespread commercial availability of “skin prick” and other allergy testing kits. It is very important for a qualified physician to make the proper diagnosis.

Is there a threshold below which peanut protein does not cause an allergic reaction?
There is considerable interest in this issue from both the food industry and peanut allergic consumers. Research on “thresholds” is ongoing but is not conclusive.  Recent results using the EuroPrevall sample and double-blind, placebo controlled food challenges done at Manchester University demonstrated that objective peanut allergy symptoms appeared with ingested peanut protein amounts of between 2.8mg and 6.6mg.  Since peanuts are 25% protein by weight, the amount of whole peanut required to cause a reaction is larger: ie about 11.2mg being the ingestible “dose” causing a reaction in the most sensitive individuals. 

With the introduction EU-wide of the Food Information for Consumers (FIC) Regulations from mid December 2014, the importance to industry and consumers of being able to use reliable information about the presence of possible food allergens could not be higher. Even if reliable thresholds forfood allergens could be established, however, real questions remain: Who will do the analysis of products to see if they comply with thresholds once they are set? What will the costs of this be and who will bear those costs?  Finally, even if thresholds could be uniformly and reliably implemented across the EU’s multi-country single market, what about products possibly contaminated by peanut (or other allergens) coming in to the EU from outside that area?

The problem is compounded by labelling which may not be reliable. Ingesting even small amounts of peanut protein can be a major problem to seriously allergic individuals, so it is recommended that everyone allergic to peanuts avoid peanut allergen entirely. They should not assume that a previously mild reaction will always be the case.

Despite media reporting about research into so-called “low allergen” or “non-allergenic” peanuts, the breeding changes that would be required to eliminate the allergenic traits out of every peanut line worldwide make this improbable. Peanut allergic consumers would not be safe in terms of all products, even if one origin producer were successful in achieving this.

Much more promising are the advances being made in oral immunotherapy and in the potential for achieving early tolerisation to peanuts in susceptible individuals, rather than in manipulating the peanut itself. See the “current directions in peanut allergy research” section for more information.

Can anything be done to manage peanut allergy and prevent a reaction?
The only certain way to prevent a reaction is avoidance—there is no treatment to prevent peanut allergy. With proper management, awareness, and education, most reactions to food allergens can be avoided.

Individuals with a food allergy should diligently read all food labels and ask questions about foods consumed away from the home (such as in school or a restaurant). In the day care or school setting, parents of a child with food allergy should educate teachers and school staff to be prepared to recognize and treat severe allergic reactions immediately and seek first aid. It is widely recommended that each food allergic child has an action plan detailing what needs to happen if they have a reaction, although statistics show that most serious reactions occur outside of school settings.

Individuals with severe allergic reactions should always carry a self-injectable form of epinephrine (adrenaline). The most recent advice is to have two injectable devices available at all times. Wearing an identity bracelet or medallion may help to alert others if they have a problem.

How is a severe allergic reaction to peanuts treated?
With proper medical treatment, most food allergic reactions are manageable. Even if all of an individual’s reactions have been mild in the past, however, there is the possibility that a future reaction could progress to a medical emergency. It is essential, therefore, that all peanut allergic individuals, particularly young people, carry and understand how to use viable auto-injectors containing epinephrine (adrenaline).

Injecting epinephrine/adrenaline does not eliminate the allergic reaction—in most instances it only relieves the immediate symptoms and allows the extra time necessary to seek emergency medical help. Anaphylaxis associated with tree nut and peanut exposure more often leads to fatal and near-fatal events than do reactions to other allergens.

Can peanuts be safely consumed during pregnancy and breastfeeding?
Yes, unless the individual is known to be allergic to them. Expert opinion has changed and no longer recommends exclusion of peanuts, peanut butter or foods containing peanuts from a mother’s diet during pregnancy and breastfeeding. This reflects research that indicated avoidance of peanuts while pregnant or breastfeeding made no difference to the incidence of peanut allergy and excluding foods such as peanuts and peanut butter could reduce the nutritional status of the mother and her child.

Can peanuts be given to infants and children?
Yes, and peanut butter is a widely used weaning food in many parts of the world. Delaying the introduction of potentially allergenic foods until 1, 2, or 3 years of age has not been shown to prevent later food allergies. In 2008, the American Academy of Pediatrics amended their earlier position and no longer recommends avoidance of foods such as peanuts as a preventive measure.

The previous advice was not to introduce peanuts before three years of age if there was a history of allergy in the immediate family. Mothers are still recommended to breastfeed for the first six months before introducing other foods.

Should peanut oil be avoided by a peanut allergic individual?
The consensus view is that refined peanut oil should pose no problem for peanut allergic individuals. The process of refining peanut oil removes the protein which would trigger an allergic reaction. Refined peanut oil (sometimes labelled as arachis oil or huile d’arachide) is commonly used as a cooking and salad oil (particularly in Asian cuisines), as an ingredient in processed foods or as an emulsifier/lubricant in body care products.

This is not the case for peanut oil which has been “cold pressed” to retain the flavour and aroma of peanuts and any oil that has been used to cook peanuts or food containing peanuts. These will contain traces of peanut protein and therefore must be avoided. Oils from other common allergenic foods such as soy, sesame and corn may also be “cold pressed”.

Though refined peanut oil it is very unlikely to cause an allergic reaction, all peanut oil is required to be labelled as a food allergen in the European Union, but this is not the case in other parts of the world.

Can a food’s smell cause a serious allergic reaction?
No. False beliefs about the danger which could arise from touching or smelling peanuts or peanut butter often cause anxiety to the parents of peanut allergic children. Research has demonstrated that a casual contact (not ingestion) with peanut protein, such as a trace of peanut butter getting on the skin of an allergic person, can cause localised reddening or itching, but this reaction does not spread from the area of contact or worsen and medication is generally not needed.

Simply smelling the aroma of peanuts is not the same as breathing in protein particles which could cause an allergic reaction in a susceptible person. The chemicals which are detected as the odour of peanuts are aromatic molecules called pyrazines and incapable of causing allergic reactions. They are not proteins. A study of peanut allergic children exposed to the smell of open jars of peanut butter did not find any allergic reactions.

Is food allergen labelling mandatory?
Lists of allergens that must be declared on labels vary. In the US, Canada and the European Union there is mandatory labelling of food allergens on food packaging, including peanut ingredients. Labelling requirements elsewhere may be quite different. Always seek the advice of a local food allergy expert organization about the reliability of labelling.

Problems arise where food is sold unpackaged, served in restaurants and other settings and bought from “take-aways” or “carry-outs”. Allergy awareness by food preparers and servers cannot be relied on. Allergen labelling is often not required in these cases. It is always safest to ask about any food and avoid it if it might contain an allergen to which a particular person is allergic.

How is the American peanut industry helping?
The American peanut industry actively supports organizations working to ensure food allergic consumers can make safe and informed choices about foods while the widest range of nutritional opportunities, including peanuts, is available to everyone else.

The industry supports clear and accurate allergen labelling on all products and the provision by the food manufacture and the food service sectors of information about peanut ingredients in foods.

It works closely with consumer-led food allergy bodies through the world-wide Food Allergy and Anaphylaxis Alliance, particularly on food allergy issues related to young people and schools.

It supports scientific research on effective measures which may reduce or even eliminate peanut allergy in the future. See the “current directions in peanut allergy research” section for more information.