Skin allergies: the virtues of broccoli and cabbage

Eating broccoli or cabbage would limit the severity of skin allergies, says a study presented Tuesday, May 16 by INSERM, which highlights 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 of Health and Medical Research (INSERM) and the Institut Curie first showed that the absence in the diet of compounds found in certain vegetables, especially broccoli and cabbage, could aggravate skin allergies in animal models.

'Aromatic hydrocarbon receptor'

It was already known that skin allergies are caused by an inadequate immune response to compounds in the environment, and that their severity varies depending on many factors, including diet. In their work, the scientists were specifically interested in food compounds that act on a molecule present in the body, called "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 a worsening of skin allergy, which was not the case for mice fed a diet containing these compounds. How to explain the biological mechanisms induced by these nutrients?

Langerhans cells

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

The scientists then showed that the compounds activating the AHR receptor also controlled the production of TGF-beta in human skin cells. "Our results suggest that an unbalanced diet could increase allergic skin reactions in humans," said Élodie Segura, an Inserm researcher who led the study at Institut Curie.