Food Allergy and the Most Common Food Allergens

Food allergy is a surprisingly common problem. If you’re affected, you can’t simply eat whatever you fancy — doing so could trigger serious health issues. In this article, we’ll take a closer look at the most common food allergens behind those unpleasant symptoms and what actually works when it comes to managing a food allergy.

Food allergy and intolerance

First things first — let’s clarify the difference between a food allergy and a food intolerance. The two terms are often used interchangeably, which, as you might suspect, isn’t ideal. A food allergy is an immune response triggered by an allergen found in a particular food. Your body identifies the allergen as a threat and releases excessive amounts of histamine into the bloodstream. This leads to the development of unpleasant symptoms.

TIP: How do I know if I have an allergy?

Food intolerance, on the other hand, is a condition where the body cannot properly process certain substances in food. This can be caused by a lack of a specific enzyme needed to digest a given substance. A classic example is lactose intolerance — an inability to break down lactose, the sugar found in dairy products. This condition is caused by a deficiency of the enzyme lactase, which breaks lactose down into easily digestible components. When the body doesn’t produce enough lactase, digestive problems follow — bloating, abdominal pain, or diarrhoea.

Unlike a food allergy, food intolerance is not life-threatening in most cases. However, it can cause uncomfortable symptoms that significantly affect your quality of life.

Read more about what food intolerance is and how to deal with it.

How to recognise a food allergy?

You’re probably wondering what the symptoms of a food allergy look like. Because everyone reacts differently to a given allergen, the signs can vary in both form and severity. The most common food allergy symptoms include:

• Itching and redness of the skin,
• rash,
• swelling,
• hives,
• sneezing,
• runny nose,
• asthma,
• abdominal pain,
• nausea,
• vomiting and diarrhoea,
• red, itchy eyes,
• in some cases, anaphylaxis.

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How quickly does a food allergy appear?

Unfortunately, there’s no one-size-fits-all answer to how long it takes between eating a food and experiencing allergy symptoms. In some people, the allergic reaction develops within minutes; in others, it can take several hours. This, of course, makes it much harder to identify the allergen responsible for the symptoms.

Main food allergens

Because food allergy symptoms can look quite similar to those of other allergies, let’s go through the most common food allergens. Knowing these should help you work out whether you’re truly dealing with a food allergy or need to look elsewhere for the cause of your troubles.

What are allergens in food?

Food allergens are substances that trigger an allergic reaction in certain people. For allergy sufferers, even simple contact with an allergen — for example while cooking — can cause uncomfortable symptoms. It’s also worth noting that some foods become safe to eat after being cooked or heat-processed. However, this should always be discussed with a healthcare professional. Don’t experiment with this on your own.

TIP: How does a meat allergy present and what can you do about it?

Which foods are common allergens?

The most common food allergens behind food allergies include:

• Eggs,
• milk,
• nuts – peanuts, walnuts, hazelnuts, almonds, cashews, pistachios,
• fish,
• shellfish – prawns, crabs, crayfish, and lobsters,
• soy,
• wheat,
• legumes – peas, lentils, beans,
• fruit – apples, peaches,
• vegetables – celery.

Learn about other types of allergens you may encounter.

How to diagnose food allergies?

There are several ways to find out whether you really do have a food allergy. We’ll be honest with you, though — it does require a visit to a doctor’s surgery. We know that when symptoms aren’t severe, seeing a doctor might not feel urgent. One reason to seek professional help even with mild symptoms could be a positive result from a home allergy test.

You can carry out the test easily from the comfort of your own home, and because it uses a blood sample, the results are reliable. If the test comes back negative but your symptoms keep getting worse, visit your GP — they’ll help uncover the real cause.

A positive result from a home food allergy test means one thing — it’s time to see an allergist. In addition to asking about your diet and lifestyle, the doctor will carry out:

• Skin tests – These can take the form of quick and simple skin prick tests. In some cases, they may be supplemented with a more sensitive intradermal test.
• Blood tests – Blood tests measure the level of specific antibodies (IgE) in response to foods.

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How to treat food allergies?

The most common approach to treating a food allergy is an elimination diet, carried out under medical supervision. An elimination diet is an eating plan that removes all foods that cause — or could potentially cause — an allergic reaction. The patient avoids these foods for several months. Afterwards, they are gradually reintroduced into the diet. This way, only the foods that genuinely trigger a reaction need to be avoided long term. A doctor or dietitian also ensures the patient gets adequate nutrition throughout the process.

TIP: What is histamine intolerance and what are its symptoms?

To relieve allergy symptoms, doctors may prescribe antihistamines and, in the case of rashes, topical creams or ointments. It’s also important to support your immune system by ensuring an adequate intake of vitamins and minerals — particularly vitamin C, vitamin D, and zinc.

You might also like: 12 tips on how to boost immunity in adults and children

Frequently asked questions