(Paris) Eating broccoli or cabbage would limit the severity of skin allergies, indicates a study presented Tuesday by Inserm, which emphasizes the importance of a balanced diet for patients suffering from these skin reactions.

In this study published in the English-language scientific journal eLife, researchers from the National Institute for Health and Medical Research (Inserm) and the Institut Curie first showed that the absence in the diet of compounds found in certain vegetables, particularly broccoli and cabbage, could aggravate skin allergies in animal models.

We already knew that skin allergies are caused by an inappropriate immune response to compounds present in the environment, and that their degree of severity varies according to many factors, including diet.

In their work, the scientists looked specifically at food compounds that act on a molecule in the body called the “aromatic hydrocarbon receptor” (AhR). These nutrients are naturally present in cruciferous vegetables, such as broccoli.

They showed that the absence of these nutrients in mice was associated with an increase in the state of inflammation in the skin and an aggravation of the skin allergy, which was not the case for mice having received a diet containing these compounds.

How to explain the biological mechanisms induced by these nutrients?

When the latter are absent, the researchers observed an overproduction of a molecule, called TGF-beta, in the epidermis of mice. And this overproduction disrupts the normal functioning of a category of immune cells, the Langerhans cells, exclusively present in the skin and functioning as a “modulator of cutaneous immune responses”.

The scientists then showed that compounds that activate the AhR receptor also control the production of TGF-beta in human skin cells.

“Our results suggest that an unbalanced diet could increase allergic skin reactions in humans,” commented Élodie Segura, Inserm researcher who led this study at Institut Curie, quoted in a press release.