Food allergies affect an estimated 6-8% of children under the age of 3, and up to 3% of adults.  Some children outgrow their allergies as they get older, but there is no known cure.

Why people develop allergies to food, is not known, but often they also have other allergic conditions as well, such as asthma, hay fever or eczema.

A food allergy is an immune system reaction that occurs soon after eating a certain food.  Symptoms can be mild, or severe – and in the worst cases people can have a life-threatening reaction known as anaphylaxis.

Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways.

With food allergies having been top-of-mind recently with press stories highlighting the dangers, it is paramount that food retailers ensure that all their customers are informed.  Whether it is a restaurant, a workplace canteen or a supermarket – all have a ‘duty of care’ to those they are serving.

Not only do they have this ‘duty of care’ but they are legally bound to give the correct information to the customer, or they will be criminally charged.  The labelling of food, and the preparation of sold food is now, more than ever, a serious responsibility for retailers and companies alike.

Food allergy or food intolerance?

Food allergy is often confused with a much more common reaction known as food intolerance.  While annoying, food intolerance is a less serious condition and does not involve the immune system at all.  However, it is essential that people are given the correct information about what may be contained in the food they are consuming.

Food intolerance or a reaction to a food eaten, may present the same symptoms as a food allergy – possibly nausea, cramping, vomiting and diarrhoea.

One of the difficult things about diagnosing a food intolerance is that many people are sensitive not specifically to the food but to an ingredient used in the preparation of the food.

With some food intolerances small amounts of problem foods can be safely eaten without any reaction.  However, if you have a true food allergy, the smallest amount of food may trigger a strong allergic reaction.

What is food allergy?

A food allergy is when your immune system identifies (by mistake) a food or substance in food as something harmful.  In order to protect the body the immune system triggers cells to release an antibody known as immunoglobulin E (IgE) to neutralise the allergy-causing food or substance (the allergen).

When that food, in even the smallest amount, is next eaten IgE antibodies pick this up and signal the immune system to release a chemical called histamine, as well as other chemicals, into your bloodstream.  Allergy symptoms are caused by all these chemicals.

For people with a food allergy getting the full information about what they are eating or the ingredients they are buying is essential.  There are some foods that are known to cause allergic reactions such as peanuts, and avoidance can be simple if the information is there to be seen.

Common foods that cause allergies

Most common foods that cause an allergic reaction in the UK are:

  • Peanuts
  • Tree nuts – walnuts, brazil, almonds, hazelnuts
  • Fruit - Apples, peaches
  • Fish
  • Shellfish – crab, lobster, prawns

Symptoms of allergies

Severe food allergy symptoms

  • Lung – shortness of breath, wheezing
  • Heart – pale or bluish skin, faintness, weak pulse
  • Throat – tight or hoarse throat, breathing difficulty
  • Mouth – Significant swelling of tongue or lips
  • Skin – many hives over body, redness
  • Gut – repetitive vomiting, diarrhoea
  • Other – feeling something bad is about to happen, anxiety, confusion

Mild food allergy symptoms

  • Nose – itchy or running
  • Mouth – itchy
  • Skin – few hives, mild itch
  • Gut – mild nausea or discomfort


This is the most extreme allergic reaction and it can be life-threatening.  Signs and symptoms include:

  • Shock with drop in blood pressure
  • Very fast pulse
  • Swollen throat and difficulty breathing
  • Tightening of airways
  • Dizziness or loss of consciousness

Untreated, anaphylaxis can cause coma or even death. Emergency treatment is therefore critical for anaphylaxis.

See your doctor

See a doctor or allergist if you have food allergy symptoms shortly after eating. If possible, see your doctor when the allergic reaction is occurring. This will help your doctor make a diagnosis.

Risk factors

The risk factors around foods are now widely known, and more people are now aware that they may have allergic reactions of all types.  Eating is one area which individuals can control, if given the correct information. Therefore, all food retailers should have in place a process for ensuring that all food ingredients are listed, and accurate records are kept.

Food allergy risk factors include:

  • Family history - If you have other allergies that are common within your family such as asthma, eczema, hives or hay fever then you are more likely to have a food allergy.
  • Other allergies - You may be at increased risk of becoming allergic to another food type, if you already have a food allergy.  Similarly, if you have other types of allergic reactions, such as hay fever or eczema, your risk of having a food allergy is greater.
  • Age - Food allergies are more common in children, especially toddlers and infants. This is probably because as their digestive system matures the body is less likely to absorb food or food components that trigger allergies.

Children typically outgrow allergies to milk, soy, wheat and eggs. Severe allergies and allergies to nuts and shellfish are more likely to be lifelong.

Other reasons for allergies

Pollen-food allergy syndrome

Also known as oral allergy syndrome, pollen-food allergy syndrome affects many people who have hay fever. In this condition, certain fresh fruits and vegetables or nuts and spices can trigger an allergic reaction that causes the mouth to tingle or itch. In serious cases, the reaction results in swelling of the throat or even anaphylaxis.

Proteins in certain fruits, vegetables, nuts and spices cause the reaction because they're similar to allergy-causing proteins found in certain pollens. When you cook foods that trigger pollen-food allergy syndrome, your symptoms may be less severe.

Exercise-induced food allergy

Eating certain foods may cause some people to feel itchy and lightheaded soon after starting to exercise. Serious cases may even involve hives or anaphylaxis. Not eating for a couple of hours before exercising and avoiding certain foods may help prevent this problem.

Conditions that are mistaken for a food allergy

Some people can describe a condition they have when eating - such as bloating or cramping – as an allergy.  Although this may not be an ‘allergy’, it is always advisable to be cautious and to ensure that everyone has all the information they may need to judge if they wish to eat the food.  Avoiding foods that cause discomfort is always advisable. 

  • Absence of an enzyme needed to fully digest a food. You may not have adequate amounts of some enzymes needed to digest certain foods. An example is the lack of the enzyme lactase - this reduces your ability to digest lactose which is the main sugar in milk products. Lactose intolerance can cause bloating, cramping, diarrhoea and wind.
  • Food poisoning. Sometimes food poisoning can mimic an allergic reaction. Bacteria in rotten fish can make a toxin that triggers harmful reactions.
  • Sensitivity to food additives. Some people have digestive reactions and other symptoms after eating certain food additives. For example, sulfites used to preserve dried fruit, canned goods and wine can trigger asthma attacks.
  • Histamine toxicity. Certain fish, such as tuna or mackerel, that are not refrigerated properly and that contain high amounts of bacteria may also contain high levels of histamine that trigger symptoms similar to those of food allergy. Rather than an allergic reaction, this is known as histamine toxicity.
  • Celiac disease. While celiac disease is sometimes referred to as a gluten allergy, it does not result in anaphylaxis. Like a food allergy, it does involve an immune system response, but it's a unique reaction that's more complex than a simple food allergy.

    This chronic digestive condition is triggered by eating gluten. Having now been more widely recognised, there is a selection of foods in most supermarkets that are gluten-free. If you have celiac disease and eat foods containing gluten, an immune reaction occurs that causes damage to the surface of your small intestine, leading to an inability to absorb certain nutrients.
  • Asthma. Asthma and food allergy commonly occur together. When they do, both food allergy and asthma symptoms are more likely to be severe.

Prevention of allergic reactions

It is the responsibility of the producer of the food to give the customer full information.  When eating in the home it is easy to know the full list of ingredients, and to control how they are handled.  When eating out it is not as easy, and the customer is then dependent on the chef, and serving staff. Information about:

  • Ingredients
  • Preparation
  • Cooking methods

should be on hand in canteens, cafes, restaurants and fast food outlets.

Allowing the customer to know what is used, how it has been prepared, and how it has been cooked.  Dependent upon the severity of the allergy, this can range from a slight inconvenience, to a total restriction of choice even on a wide menu.

Avoidance of any foods that cause signs and symptoms is the simplest way to prevent an allergic reaction. 

Here are some tips if you know you have a food allergy:

  • Know what you're eating and drinking. Be sure to read all food labels carefully when buying pre-packed food. In restaurants, cafes and canteens, ask the cooking staff and/or chef for full details of the food being offered.
  • If you have already had a severe reaction, wear a medical alert bracelet or necklace that lets others know that you have a food allergy in case you have a reaction and you're unable to communicate.
  • Talk with your doctor about prescribing emergency epinephrine. You may need to carry an epinephrine autoinjector (Adrenaclick, EpiPen) if you're at risk of a severe allergic reaction.
  • Be careful at restaurants. Be certain the staff are aware that you absolutely cannot eat the food to which you're allergic, and you need to be completely certain that the meal you order doesn't contain those food types. Also, make sure food isn't prepared on surfaces or in pans that contained any of the food to which you're allergic.

    Don't be reluctant to make your needs known. Restaurant staff members are usually more than happy to help when they clearly understand your request.

Food allergies and how they impact on us all

More and more food retailers and restaurants are working with their customers to make the labelling of food, and the offering of food, totally clear and understandable for all. 

Paradoxically our emphasis on making sure that infants are raised in a clean and germ-free environment may well be contributing to increasing food allergies in later life. 

This is not something that will be disappearing so that anyone offering food to the public or to their staff needs to be totally transparent about the ingredients used, and the likelihood of cross contamination.  An ability to offer a range of foods across a variety of diets is needed more than ever. 

Anywhere that food is sold or eaten is in reality a place of danger for some people.  Retailers and restaurateurs need to make sure that they are able to give their customers and staff all the information they need to be kept safe. 

Labelling for packaged foods – whether ingredients or a complete meal – has strict guidelines, and these need to be followed. 

Within the kitchen ensuring that there is no cross contamination with foods that are likely to cause a reaction needs careful planning and consideration.  Everything needs to be reviewed, from the sourcing and handling of the raw ingredients, through to the preparation and cooking.

Food allergies need to be taken seriously, for some people they can be a matter of ‘life or death’.

For assistance in ensuring your staff are fully trained and have all the available information on allergies and ingredients to give to those they are serving, speak to our food service consultants at Ramsay Todd.