Food allergy, food intolerance, cross-allergy: let’s put ourselves in the picture!

What is a food allergy? And what is food intolerance?

Allergy, including food allergy, is a response given by the immune system that develops to certain environmental conditions, compounds, or the consumption of foods. Most often, reactions are mediated by IgE antibodies. That is, the body produces immunoglobulin E antibodies against certain allergens, such as pollen, dust mites or food. These reactions can develop rapidly and can cause severe symptoms, such as anaphylaxis, and therefore require a medical diagnosis and a strict avoidance or treatment strategy. Evidence-based diagnostics usually combine a detailed medical history with objective tests, such as measuring specific IgE levels or skin prick tests. In some cases, a supervised oral food challenge test or the use of diagnostic algorithms may also be used.

Food intolerance refers to adverse physiological responses based on non-immunological mechanisms after consuming certain foods. Enzyme deficiencies, metabolic disorders, and factors related to digestion and the structure of foods may also play a role in its development.

How many food allergies are there among us?

In European adults, the frequency of “probable food allergy” (symptoms + specific IgE sensitivity) ranges from 1–6%, depending on the country. In some regions, allergens such as peanuts and oilseeds occupy a prominent place. The proportion of the allergic population can be around 6–10% in some regions. In Hungary, the incidence of food allergy among adults is approx. 1–2%, and in children it can be much higher, around 6–7%, especially in infancy and early childhood. The type of food that causes allergies is also age-related – it can be different for children and adults. For example, in adulthood, the number of people with allergies to oil seeds, peanuts, fish, shellfish/seafood, certain fruits (e.g. apples, peaches) and nuts is much higher.

How many of us have food intolerances?

A food intolerance is a non-immunological adverse reaction to food that affects the digestive system and usually causes delayed symptoms. In contrast to food allergies, where the immune system (often IgE antibodies) is actively involved in the reaction, in the case of intolerance, the symptoms are due to enzyme deficiencies, metabolic disorders or improper breakdown of certain components of the food. Symptoms can vary from person to person and often manifest as digestive complaints: bloating, diarrhea, abdominal pain, but headaches, fatigue or skin symptoms may also occur. The diagnosis of food intolerances is usually based on an elimination diet and symptom observation, rather than on blood tests or skin tests, since the immune response is not affected.

In our country, several foods and food ingredients can be associated with food intolerance. Lactose intolerance (milk sugar sensitivity) is the most common food intolerance worldwide. Those affected lack or have a reduced amount of the lactase enzyme, which is responsible for breaking down milk sugar. Symptoms: bloating, abdominal pain, diarrhea after consuming dairy products. In some cases, skin problems may also occur.

Fructose intolerance (fruit sugar intolerance) can be inherited (rare) or acquired (more common), in the latter case the small intestine is unable to properly absorb fructose. It can be triggered by fruits, honey, syrups, and soft drinks, and can cause digestive system complaints.

The symptoms of gluten (celiac disease, i.e. not a form of celiac disease!) may resemble celiac disease, but there is no immunological or histological evidence.

Histamine intolerance develops due to an enzyme deficiency (DAO enzyme deficiency), which inhibits the breakdown of histamine. The foods with the highest histamine content are aged cheeses, wine, smoked meats, tomatoes, chocolate, and fish. Symptoms may include: headache, redness, itching, palpitations, stomach upset.