Why strawberries and tomatoes can be a health hazard for many people

Allergy potential can depend on the type of vegetable or fruit

Tomatoes and strawberries are very popular and are among the most eaten vegetables and fruits. However, many people experience allergic reactions when they eat the otherwise healthy foods. In particular, people with birch pollen allergy show such reactions. A Munich research team has now identified strawberry and tomato varieties that contain fewer allergens.

Maybe people who are allergic to strawberries and tomatoes will soon no longer have to do without them. A team of researchers from the Technical University of Munich (TUM) was working on the current allergy potential of strawberries and tomatoes and found that both the respective variety and the preparation methods influence it. The research results were recently published in the specialist journals "Plos one" and "nutrients".

Food allergies are constantly increasing

According to the TUM experts, the occurrence of food allergies has increased steadily in recent decades: around four percent of adults and around five percent of children have already been affected. The studies focus on tomatoes (botanical: Solanum lycopersicum) and strawberries (botanical: Fragaria x ananassa), which contain allergenic proteins and often trigger allergic reactions.

The triggers are similar to those of birch pollen allergy

According to the scientists, the allergenic proteins in tomatoes and strawberries are similar to those of birch pollen. This similarity could also lead to a food allergy as a result of a birch pollen allergy. In Italy, up to 16 percent of the population is affected by a tomato allergy. According to the researchers, 30 percent of those who are allergic to birch pollen also suffer from allergic reactions to strawberry fruits.

Immune reactions can manifest themselves in a variety of ways

Allergic reactions to tomatoes and strawberries can manifest themselves in a variety of ways. The researchers report that an allergy can affect the skin (itchy rash, urticaria, or dermatitis) that irritates the mucous membranes, causes a runny nose and can also lead to abdominal pain. Food allergy sufferers would often experience symptoms after eating fresh fruit or vegetables, whereas processed foods often do not trigger any reactions.

A protein is the main culprit

In two studies, the team led by Professor Dr. Wilfried Schwab from the Chair of Biotechnology of Natural Products at TUM quantify the triggering protein in the different strawberry and tomato varieties that the main cause of the allergic reactions is (Sola l 4.02 for tomatoes and Fra a 1 protein for strawberries).

Find the best possible variant for allergy sufferers

In addition to different types, the size, shape and color were also taken into account. Furthermore, the experts also examined the possible influence of organic and conventional growing conditions and various processing methods from sun drying to oven drying to freeze drying. The aim of the research was to find the best possible variants for allergy sufferers.

Type and heat make the difference

Ultimately, the team examined twenty-three different types of tomato and twenty different types and sizes of strawberry. The results show that the allergen content in the different strawberry and tomato varieties fluctuates greatly. In addition, the heat factor seems to have an impact. When the fruits were exposed to heat during the drying process, less allergenic proteins were present.

The perfect fruit for allergy sufferers soon available?

The growing conditions, however, appear to be negligible in the development of allergenic proteins. Based on the research results, it should now be possible to grow hypoallergenic tomato and strawberry varieties that can also be eaten by allergy sufferers, according to the study authors. (vb)

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