Food intolerance vs allergy: do I have a food allergy?

 

What is a food allergy, and what is a food intolerance? An allergy to food can, in the worst-case scenario, be deadly. When we talk about food intolerances, we instead talk about symptoms that range from discomfort to acute pain, rather than a life-threatening condition. The real challenge in many cases is to find out exactly what it is that you cannot tolerate.

Both food allergy sufferers and those with a food tolerance alike can quite easily be picked out from the crowd by the way they hover in supermarket aisles, studying ingredient lists. These people have to change their diets and steer clear of possible food triggers to avoid any nasty surprises after eating that can range from stomach rumbling, severe flatulence, a food allergy rash and dizziness to anaphylactic shock. 

So, to help you out, we have broken down the differences between a food allergy and a food intolerance, giving you somfe pointers on how you might be able to discover which of the two affects you. We’ll tell you about food intolerance and food allergy symptoms, treatment and diagnosis – and you’ll find out which steps to take to alleviate symptoms, such as following an elimination diet or taking a home health test.

What is a food allergy?

When you have an allergy, your immune system reacts strongly to an otherwise harmless substance. The substances which can trigger allergies are known as allergens. These different proteins may be present in pollen, animal hair, the faeces of house dust mites or even in food.

What is an allergen?

 

An allergy is triggered by a sensitisation towards an allergen. This means that the body will produce certain IgE antibodies in an excessive amount. Each of these immunoglobulins (the ‘Ig’) specialises in keeping specific substances out of the body. In doing so, the immune system will combat bacteria, viruses and worms – but unfortunately, also harmless allergens.

IgE antibodies bind to receptors on mast cells, which are cells of the immune system. Laboratories can detect the increased number of IgE antibodies in the blood and assign these to their corresponding allergens – and this is how an allergy test by blood sampling works. If the allergen is present in the body again, the allergen will bind to the IgE antibodies and cause the mast cell to release messenger substances, such as histamine. Histamine then promotes inflammation and, in so doing, triggers different food allergy symptoms.^{[5, 6]}

How does a food allergy develop?

Allergies are today talked of as a disease of modern civilisation. The number of allergies has increased steadily over recent decades. Scientists are not quite sure why this has been the case. A popular explanation is the hygiene hypothesis, which has blamed the frequency of allergies today on our tendency to avoid dirt and germs.^[9] Nevertheless, genetic factors also seem to play a role.

Can allergies run in the family?

Is there a connection between allergies and human genetics? As a rule, nobody is born with an allergy. But humans can have an inherited predisposition when it comes to developing an allergy. In other words, you can have a significantly higher risk of developing an allergy.

This often applies to allergies in general – that is, the children of parents with hay fever are susceptible to all allergies, whether it be to pollen, animal hair or food. This also applies to other topical or contact diseases, which are closely related to allergies and which often occur together with them (such as with atopic dermatitis and asthma).^{[10, 8, 11]}

For an unborn baby, the womb is its home, and this influences how its body develops. As such, a mother’s diet can also influence the development of allergies. Giving birth by caesarean section and at an advanced age also seem to increase the risk of developing a food allergy.^[8] To find out about the ideal diet during pregnancy and breastfeeding, visit our Health Portal article for more insights.

How true is the hygiene hypothesis?

What is the hygiene hypothesis and what does it have to do with food allergies? The hygiene hypothesis is based on the observation that allergies are particularly prevalent in cities and much less common among children raised on a farm.

The theory points out that in the hygienic environments we inhabit in the Western world, our immune system rarely encounters foreign bodies, such as pathogens, worms and parasites. Our bodies’ defences have comparatively little to do and only rarely are challenged by harmless substances such as food and pollen – and this is how an allergy arises.^{[10, 9, 12]}

Whether we develop an allergy over the course of our lives is decided during the first months of us being alive – and perhaps even in the womb. It therefore depends on the environment in which babies live at the beginning of their lives.

Does gut health affect allergies?

The microbiome (also known as the intestinal flora) describes the composition of the billions of bacteria that inhabit our gut. This microbiome plays a key role in helping our immune system develop from early childhood onwards. Researchers suggest that our modern way of life affects our gut flora, which, in turn, can have an impact on the development of allergies.^[13] You can find out more about why your gut microbiome is important in our dedicated Health Portal article, as well as which foods can boost gut health in general.

A study from Estonia showed that Estonian children, who still grow up relatively frequently on farms and spend a lot of time outdoors, boasted better intestinal bacterial colonisation than children from Sweden, who are less likely to grow up on farms.^[14]

A gut microbiome test will indicate how healthy your gut bacteria is – and how to optimise it for optimal immune system, digestive and skin health. Usually, all that is required is a stool sample, which you can collect with a kit given to you by your doctor or with a kit provided to you when you order a test online.

Is there a link between breastfeeding and food allergies?

For the immune system to develop healthily, mothers should ideally breastfeed their infants for at least four months. Until just a few years ago, strict nutritional guidelines were recommended. To reduce the risk of allergies, breastfeeding women had to avoid eggs, nuts, dairy products and wheat products. Experts also advised against contaminating baby porridge with gluten-containing grains. And fish was just as much taboo, as were celery and carrots.

New studies have turned these recommendations on their head. They show that children are more likely to tolerate foods if they have been in contact with them while still in the womb or feeding on breast milk.^[15] Of course, this only applies if the child has not already developed an allergy!

Is it possible to prevent allergies?

The emergence of an allergy is a complex process that scientists still do not fully understand. There are thus no official recommendations on allergy prevention.

Medical guidelines, however, provide recommendations that make an allergy a little less likely. They are aimed at at-risk families – that is, at families in which allergies, atopic dermatitis or asthma also occur. Recommendations furthermore include:^[16]

• The mother and child should not refrain from consuming allergens as part of the diet, since even the consumption of fish by the mother can protect against allergies.
• During pregnancy, mothers should avoid tobacco smoke.
• Children and pregnant or breastfeeding women should not come into contact with mould.
• Cats should not be kept as pets – unless the child is at a high risk of developing a cat allergy. In this case, exposure to cats can actually have a positive effect.
• There should be as minimal exposure to vehicle exhaust as possible.

Cross-reactivity: what does cross-allergy mean?

It is not the foodstuff itself that triggers an allergic reaction, but rather certain proteins within them that act as allergens. Sometimes, different types of these proteins are so similar that the body can not tell them apart. This is called cross-reactivity or a cross-allergy.

This is when the body is sensitised towards one allergen but also reacts to the other. This happens with foods – for example, those allergic to peaches often are allergic to apples. In addition, a birch pollen allergy sometimes leads to a cross-reaction with fruits, vegetables and nuts. Surprisingly, even latex often triggers cross-allergies – to kiwis, bananas and avocados.

Foods and their potential cross-allergies:^[17]

Allergic to	Cross-reaction to	Risk of cross-allergies
Cow’s milk	Goat’s milk	92 per cent
Cantaloupe melons	Watermelons, bananas, avocados	92 per cent
Shrimps	Crabs, lobster	75 per cent
Peaches	Apples, plums, cherries, pears	55 per cent
Pollen	Apples, peaches, honey melons	55 per cent
Salmon	Swordfish, sole	50 per cent
Walnuts	Brazil nuts, cashews, hazelnuts	37 per cent
Latex	Kiwis, bananas, avocados	35 per cent
Wheat	Barley, rye	20 per cent

What are common food allergy symptoms?

Experts distinguish between different types of allergy. The most common forms of allergy are those of the immediate type – namely, allergies where food allergy symptoms occur immediately after you have consumed the allergen. Food allergies are most often immediate-type allergies. A person allergic to peanuts feels symptoms such as a furry tongue and food allergy rash between a few seconds to around 20 minutes after eating.^[7] Delayed immediate reactions are also possible, meaning an allergic reaction can occur after four to six hours.

A variety of symptoms may indicate the presence of an allergy or intolerance. Some are mild and barely noticeable, while some cannot be overlooked – and others are even very severe, with symptoms such as an anaphylactic shock. Food allergies do not always just affect the mouth and gastrointestinal tract; they also impact the skin and respiratory tract.^{[10, 7]}

Food allergy symptoms: what are the specific signs of a food allergy?

 

During an allergic reaction, the following symptoms frequently occur:

• Redness and wheals on the skin (nettle fever)
• Diarrhoea, vomiting and abdominal pain
• A burning sensation in the mouth, swelling of the mucous membranes and tongue
• Breathlessness or allergic asthma
• A fall in blood pressure

Anaphylaxis: what is the worst scenario of a food allergy?

The most severe form of an allergic reaction is an allergic shock, which is also referred to as an anaphylactic shock. The causes of this are usually insecticides, medicines and, especially in children, food. But foods such as nuts, soy, shellfish, milk and eggs can also cause anaphylaxis.

During an anaphylactic shock, large amounts of histamine are released, resulting in severe dilation of the blood vessels. Blood pressure falls rapidly, while dizziness, fainting and even death can occur in the worst-case scenario.

If you are aware that you are at risk of having an anaphylactic shock, you should respond quickly if more severe food allergy symptoms occur and call the emergency services immediately. While waiting for the ambulance to arrive, the individual in shock should be placed in the shock position – that is, lying down with their legs up. At-risk patients also often carry an emergency kit containing an adrenaline pen. This emergency medicine will ensure that the shock subsides.^{[5, 6]}

Depending on the severity of an allergy, even the smallest amounts of an allergen can trigger an anaphylactic shock – such as traces of nuts on your partner’s lips or traces of soy in certain foods.^{[5, 6]}

What can make allergy symptoms worse?

Just because you have an allergy, this doesn’t mean you will automatically respond to the smallest amount of the allergen. A reaction threshold exists, meaning that you need exposure to a certain amount of the allergen before food allergy symptoms occur. As an example, peanut allergy sufferers often have a very low reaction threshold, with a small crumb of a peanut being enough to lead to a furry tongue and swollen neck.

Stress, sport and infections can also lower your reaction threshold. This will make you more likely to suffer from an allergic reaction. Studies have shown that stress can make the symptoms of allergy worse and more likely to occur. If you suffer from an allergy and are often stressed out, seek out relaxation techniques, such as yoga, training and progressive muscular relaxation. You can read more about these relaxation techniques and the affect stress has on our bodies in our article on emotional resilience.

Infections can also set off allergies. A high temperature can lead to increased blood circulation, which, in turn, can allow more allergens to enter the bloodstream. With stomach infections, allergies are aggravated by a larger quantity of undigested proteins crossing the mucous membrane. As a result, such proteins affect the sensitised immune system and are more likely to trigger an allergic reaction.^[30]

Alcohol is also discussed among scientists as a factor exaggerating allergic reactions. In some case studies, food allergy symptoms were exacerbated under the influence of alcohol, and for alcoholics, the number of IgE antibodies is often greater. Conclusive scientific evidence for this correlation, however, does not yet exist.^[30]

Do I have a food allergy: how do you test yourself for food allergies?

Do you suspect that you can’t tolerate certain foods due to symptoms such as a food allergy rash, furry tongue or gastrointestinal discomfort? Then it may be worthwhile for you to take a food allergy test. There are a handful of common tests that can detect allergies:^[29]

• prick test
• blood test for IgE antibodies
• hair test
• elimination diet
• oral provocation test

The prick and blood tests merely detect a sensitisation towards certain allergens. Elimination diets and provocation tests can serve to find out whether an allergy is behind the sensitisation.

Food allergy treatment: is there a cure?

Unfortunately, there is no such thing yet as food allergy treatment. Once you have an allergy, you have to live with it, unless it resolves itself. However, based on a reliable diagnosis, you can avoid the triggers, relieve discomfort with medications and arm yourself with an emergency kit to treat anaphylaxis.

Avoid triggers and eat a balanced diet

This much is clear – if you have a food allergy, you should stop consuming that food, even in small quantities. If your allergy is accompanied by severe discomfort or even the risk of anaphylactic shock, you should carefully check out the ingredients on food packaging. Heavily processed foods, in particular, often contain ingredients that you would not necessarily expect.

The UK Food Standards Agency requires food manufacturers to clearly label the 14 most common triggers of allergies and intolerances on their products: celery, cereals containing gluten (including wheat, rye, barley and oats), crustaceans, eggs, fish, lupin, milk, molluscs, mustard, tree nuts, peanuts, sesame, soybeans and sulphur dioxide and sulphites.

If you only have reactions to one or two foods, it is often easy to eliminate them from your diet and replace them – especially in today’s world, where there has been a noticeable boom in the food substitute industry. However, if you or your family have a lot of food allergies, cooking meals can become quite a mission. Experts recommend dietary or nutritional advice in such cases. You will then learn how to avoid allergens while still maintaining a balanced diet.

Can I use antihistamine as food allergy treatment?

Antihistamines, which are also known as anti-allergic tablets, weaken or even block the messenger histamine. In this way, they can combat allergic reactions throughout the body. Such tablets are used for hay fever, but can also relieve minor food allergy symptoms, such as rashes, palatal itching or nausea. The most common active ingredients are cetirizine and loratadine, and these are available as drops or tablets over the counter in many pharmacies.

With an anaphylactic shock, however, the effect of antihistamines is usually not sufficient. That is why people with severe allergies to more dangerous allergens, such as nuts and shellfish, often carry an emergency kit with them. The emergency kit includes an adrenaline pen which is injected into the thigh, glucocorticoids and, for asthma sufferers, an inhalation spray.

What is a food intolerance?

Food intolerances include intolerances to lactose, fructose, sorbitol, histamine and IgG4-mediated intolerances. Coeliac disease (gluten sensitivity)ist also often counted as an intolerance, although it is an autoimmune disorder.

According to experts, 15 to 20 per cent of the world’s population are affected by intolerances – and women more so than men.^{[1, 2]} The causes of intolerance are not always obvious, with possible factors including genetic predisposition and environmental influences.^[3]

Many people believe that they may have an intolerance to a food – but in reality, this only affects a fraction of them. In a UK survey, 20 per cent of people believed that their household suffered from food intolerances. Investigations showed, however, that of these 20 per cent only two per cent were affected by real intolerances.^[4]

^{What are typical food intolerance symptoms?}

Intolerances are usually delayed, unlike allergies. If you eat something that you can not tolerate, it can take hours for food intolerance symptoms to appear. This often makes it difficult to detect an intolerance and to find out what food is responsible for it.

The symptoms of intolerance are usually noticeable in the gastrointestinal tract. Unpleasant flatulence is typical, but it can also lead to nausea, constipation, diarrhoea and vomiting. Other possible food intolerance symptoms include:^[31]

• Headaches and migraine
• Whistling breath sounds and a runny nose
• Rashes
• Fatigue

Tip: If you’re not sure about where to start when it comes to food intolerance testing, you can keep a food diary to keep track of your meals and when you experience symptoms, as well as which symptoms you experience. This will undoubtedly help you narrow down the foods you could be intolerant to before you take every food intolerance test under the sun.

What causes food intolerance: the 3 most common food intolerances

The causes of a food intolerance is often unclear and unknown. Scientists today already more or less understand a number of intolerances. We tend to know roughly what’s going on in our guts and why sufferers can no longer tolerate certain foods. Well-researched intolerances include lactose, histamine and coeliac disease, fructose and sorbitol.

Did you know that symptoms of an intolerance can also originate in the psyche? For example, your brain may associate traumatic memories with a certain kind of food. Sometimes the body will then react with discomfort when you consume the food again.^[4]

1. Lactose intolerance

Chances are, you have already heard of lactose intolerance. Lactose is a sugar found in milk and many dairy products. In the United Kingdom, lactose intolerance affects up to eight per cent of the population.^[32] In other regions, especially in East Asia, it is even more common: In fact, it has been reported that between 70 and 100 per cent of adults are affected by lactose intolerance in these regions.^[33]

In affected individuals, the specific enzyme that breaks down lactose occurs at low levels in the intestine. The body can not process the lactose properly, leading to flatulence and abdominal pain.

Did you know that humans started consuming milk from domesticated animals long before the Bronze and Iron Ages?^[34] This is why Eurasians are able to better tolerate lactose than other citizens around the world.

2. Gluten intolerance (coeliac disease)

Coeliac disease is not technically an intolerance, but a chronic autoimmune disease. We've included it in this list because it has similar consequences: In this case, the body reacts to the protein gluten and people who suffer from the disease must avoid foods that contain gluten.

With coeliac disease, the gluten triggers an immune reaction that leads to an inflamed gut mucosa and stomach discomfort – and long-term to nutrient deficiency and consequential symptoms, such as osteoporosis and anaemia. Gluten is found in many cereals – for example, in wheat, spelt and rye, as well as in many processed foods. This can therefore be frustrating for anyone with a gluten intolerance.

3. Histamine intolerance

Histamine intolerance is also referred to as a pseudoallergy. Like a food allergy, histamine levels lead to symptoms such as flatulence, dizziness and a runny nose. But while immune cells release too much histamine during an allergic reaction, a histamine intolerance is caused by a lack of a specific enzyme in the gut and blood that breaks down histamine in food. Histamine-rich foods such as red wine, mature cheeses and cured sausage can then trigger these food intolerance symptoms.

• monosodium glutamate (MSG)
• caffeine
• alcohol
• artificial sweeteners
• toxins, viruses, bacteria or parasites
• artificial food colours, preservatives or flavour enhancers^[55]

How do doctors test for food intolerance?

According to theories, the production of certain IgG4 antibodies increases all the more when we cannot tolerate a certain food, leading to various defence and inflammatory reactions. This leads to an IgG4-mediated intolerance. These reactions and the associated symptoms only occur after a delay, and sometimes only hours or days after the food was eaten. The number of IgG4 antibodies can be determined using a blood test – a food intolerance test. The result might then indicate you an intolerance.^[35]

Some researchers and professional institutions have criticised that the IgG4 concentration only provides information on the extent to which certain foods were eaten and that it is not clinically relevant. It instead points towards an immune tolerance rather than an intolerance. Thus far, there has been no large-scale study investigating the link between IgG4 levels and food reactions.^{[36, 4, 37]}

Intolerance to histamine, lactose, fructose and sorbitol as well as coeliac disease cannot be detected using an IgG4 intolerance test. In each case, other blood or hydrogen gas tests are required.

Are food intolerance tests worth it: what can I do with my test results?

An increased number of IgG4 antibodies does not mean that you cannot tolerate a food. However, you can still deliberately omit the foods identified in the test from your diet and check whether your symptoms start improving. If the test shows a clear reaction to a food, remove it from your diet for two weeks. If your symptoms improve, then this is an indication that an intolerance might be present. You can then slowly reintroduce the food into your diet to see if symptoms return.

Make sure that, while you cut certain foods out of your diet, you manage to receive all the nutrients that you need, including vitamin B12, calcium, magnesium, zinc, and iron. If you need to avoid a food for the long term, you should discuss whether certain dietary supplements could be a solution for you.

Food intolerance vs allergy – at a glance

Food intolerance vs allergy: what’s the difference?

What is the difference between allergy and intolerance? A food allergy, as it is defined, is always a reaction of the immune system in which specific antibodies play a role, usually the IgE antibodies. This must be differentiated from food intolerance that causes non-immunological reactions to food. Instead of incompatibility, the term ‘intolerance’ is often used.

What is a food allergy?

With a food allergy, our immune system tries to combat usually harmless proteins called allergens that are found in foods. The mast cells of our immune system release histamine, and this causes inflammation that can bring about discomfort in the whole body.

What are common food allergy symptoms?

Food allergy symptoms include gastrointestinal discomfort, palatal itching and a furry tongue. However, reddening, itching and a food allergy rash on the skin as well as respiratory complaints and even asthma are also common. In rare cases, a fall in blood pressure and an anaphylactic shock might occur.

Which foods can trigger an allergy?

Theoretically, many foods can trigger allergies. In practice, however, just a few foods are responsible for more than 90 per cent of all allergies. These include cow’s milk, eggs, peanuts, nuts, soy, wheat, fish and shellfish.

How can I recognise a food allergy?

If a food allergy is suspected, one of the things you can do is take a blood test. The test determines the numbers of certain IgE antibodies in your blood. If a certain IgE level is elevated, you are sensitized to the relevant food. Then you can avoid the food temporarily to see if your symptoms are alleviated.

How do you treat a food allergy?

Unfortunately, food allergies can not be treated. Once you have them, you have to live with them, unless they go away by themselves. However, based on a reliable diagnosis, you can avoid the triggers, relieve discomfort with medications and arm yourself with an emergency kit to treat anaphylaxis.

What is a food intolerance?

In the case of an intolerance, symptoms do not arise through immune reactions as they do with an allergy. Often, the gut has problems processing certain ingredients of foods, such as gluten, histamine, lactose or fructose.

What are typical food intolerance symptoms?

In contrast to a food allergy, food intolerance symptoms are often not immediate. Sometimes symptoms only appear after hours or days. Typical symptoms include gastrointestinal complaints, and particularly flatulence, headaches and migraines, runny nose, rashes and fatigue.

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