Allergenic foods

More than 120 foods have been described as causing food allergies. However, allergy experts only consider a limited number of those to be of public health concern.

The foods that most commonly cause serious allergic reactions on a worldwide basis are:

  • cereals containing gluten
  • milk
  • egg
  • tree nuts
  • peanuts
  • soybeans
  • fish
  • shellfish

Most countries require labelling of common allergy-causing foods, but these may differ between geographical areas due to dietary preferences.

As a result, some countries have chosen to include additional foods on their list of what must be declared on food labels.

See EU legal requirements for more information about current labelling regulations in the EU. These may change over time in the UK.

InformAll allergenic food database

We have created a database with information on all the foods that have been reported to cause allergy.

The InformAll database has summaries about each food, which are suitable for a wide audience.

In addition, each food contains a more technical part with a section on the clinical characteristics of the allergy (such as symptoms, and diagnosis) and a section on biochemical information about the allergens (e.g. allergen stability towards different processes).

Overviews by group

As well as the A-Z list above, we have divided the foods in the database into groups to make it easier for you to find brief information on the food(s) you are looking for.

Some foods appear under more than one group. For example, you will find peanut not only under legumes, which is the botanically correct classification, but also under nuts and seeds as peanuts are often used in the same way as many tree nuts.

Nuts and seeds

This group includes true tree nuts (e.g. Brazil nuts, hazelnuts, walnut and pecan), and non-cereal seeds such as mustard and sesame.

The severity of symptoms to these allergens ranges from slight itching of the mouth and tongue (oral allergy syndrome) to severe life threatening symptoms.

The number of people with sesame allergy is relatively low,but they often experience severe and life-threatening reactions.

Nut and seed allergens are primarily ‘storage’ proteins which are present in high quantity as a source of carbon and energy for the growing seedling.


Cereals and grains

Wheat allergy is not very common,but may cause life threatening symptoms when the affected person exercises after after eating wheat-containing foods. Gluten hypersensitivity (coeliac disease) is not the same as wheat allergy. It is caused by gluten in wheat, rye and barley and for some also in oats. Coeliac disease is much more common than wheat allergy, and occurs in up to 2% of the European population. Seed storage proteins (such as wheat gluten) and other proteins present in grain to protect it from attack by moulds and bacteria, have been found to be major allergens. 

  • Barley
  • Buckwheat
  • Maize; corn
  • Oat
  • Rice
  • Rye
  • Wheat; breadmaking wheat; pasta wheat; Kamut; spelt
Legumes (including peanut)

This group of foods includes beans, peas and lentils. Peanut is botanically a bean.

Peanuts are one of most allergenic foods and the most frequent cause of very severe and occasionally fatal reactions.

Allergy to peanuts is often established in childhood and usually maintained throughout life.

Some peanut-allergic persons are so sensitive that only very tiny amounts of peanut can cause a reaction. Therefore, the cross contamination of materials on utensils used for serving foods can be enough, in some individuals, to cause a reaction.

Legumes have multiple allergens which are present in the raw and cooked foods. The main allergens are the proteins used by the seed as a food store for it to grow into a seedling.



Allergic reactions to fruit may be relatively mild and limited to the mouth and throat (itching of the lips, mouth, throat, and swelling of the lips, tongue, throat, and palate).

This is called oral allergy syndrome. These mild reactions may occur in people allergic to pollen e.g. birch pollen, when they eat certain fruits.

Cooking destroys the pollen related fruit allergens. Therefore cooked fruits are often safe for people with pollen-related fruit allergy.

Other reactions to fruit may be more severe, for example peach allergy as found in Southern Europe. The peach allergen is heat-stable and therefore also found in juice and other heated products.

Persons allergic to latex (found, for example in latex gloves) may also have allergic reactions to fruits like banana, avocado and kiwi. The reactions occur in 30-80% of latex allergic persons and are often severe.


Allergic reactions to vegetables may be relatively mild and limited to the mouth and throat (itching of the lips, mouth, throat, and swelling of the lips, tongue, throat, and palate). This is called oral allergy syndrome. These mild reactions may occur in people allergic to pollen (e.g. birch pollen) when they eat certain vegetables. Cooking destroys the pollen related vegetable allergens, and thus cooked vegetables are often safe for people with pollen related vegetable allergy. Other reactions to vegetables may be more severe, for example celery(celeriac or celery root)allergy occurring most frequently in Central Europe. The celery allergen is heat stable and therefore also found in soups and other heated products.Stem celery is generally less severe, probably because the stem contains lower levels of the allergen molecules.

Herbs, spices and flavourings

Ingredients used to add flavour to other foods can contain allergens.

Examples include aniseed, camomile, garlic, sesame and mustard. Although these are typically present in small amounts in a meal, severe and occasionally life threatening allergic reactions can result.

In many cases cooking can prevent an allergic reaction. However, by their nature many herbs and spices are added fresh to season foods and are therefore eaten uncooked.

Shellfish (including snails)

This group includes crustaceans such as crabs, shrimp and lobsters, and molluscs such as oysters and snails.

Shellfish allergies are most commonly seen in adults, particularly those living in regions where shellfish is often eaten.

Researchers have estimated that 75% of individuals who are allergic to one type of crustacean (shrimp, lobster, crawfish or crab) are also allergic to other types.

As crustaceans and molluscs (oysters, squid, scallops) contain the same type of proteins some people may react to both groups of foods.

Symptoms range from itching and swelling of the mouth and throat (oral allergy syndrome) to life threatening reactions.

Symptoms most often occur when the seafood is ingested, but can also occur when raw seafood is handled and even after inhaling steam while crustaceans such as shrimp is being cooked.

Cooking does not appear to destroy the allergens in crustaceans and molluscs.

Shellfish allergens are usually found in the flesh and are part of the muscle protein system, while in foods such as shrimps, allergens have also been found in the shells.

Fish and frog

The major allergens in fish are flesh proteins, which are very similar in all kinds of fish. This is why people allergic to cod tend to be allergic to fish such as hake, carp, pike, and whiting as well.

As with shellfish allergy, sufferers are most often from regions of high fish consumption.

Fish allergy is sometimes confused with histamine (scombroid) fish poisoning, which is a toxic reaction to histamine in spoiled fish. The reaction is similar to an allergic reaction (swelling, hives, wheezing, etc.)

Cooking appears to have little effect on fish allergens. Furthermore, some fish allergic persons can get allergic symptoms due to the steam (airborne allergens) from cooking fish.

Frog allergy is rare, but is in this section because it seems to occur after individuals develop allergy to fish in most cases.

Milk and egg

Milk allergy is far more common in children than in adults. 90% of milk allergic children lose the allergy by the age of three. It is extremely uncommon for adults to have milk allergy.

Many adults, however, cannot tolerate milk because of an inborn deficiency in the ability to break down the milk sugar, lactose.

The majority of milk allergic children have two or more symptoms. About 50-70% have skin symptoms, 50-60% have symptoms from the stomach and gut, and 20-30% have symptoms from the airways. Severe and life-threatening symptoms may occur in 10% of the children.

Milk contains several different allergens. People are usually allergic to more than one kind of milk protein.

The proteins from cow’s milk are very similar to those from goats and sheep, and can cause the same sorts of reaction in cow’s milk-allergic subjects. Therefore, goat’s or sheep’s milk cannot be used as a cow’s milk substitute in allergic individuals.

Allergy to eggs is one of the most common food allergies in children. More than half of the children outgrow their egg allergy before adulthood.

Egg white contains the main egg allergens.

The eggs of other poultry, such as ducks, are very similar to those of hens and can cause reactions in egg allergic individuals.