What we eat can cause allergic reactions on the skin, this fact is known, just think of strawberries or chocolate in predisposed people. But the diet can also help fortify the skin barrier and treat or prevent skin allergies, such as atopic dermatitis triggered by dust mites. This emerges from recent scientific research published in the journal Mucosal Immunology by a Swiss team from Lausanne University Hospital in collaboration with a group of Australian scientists (Trompette et al, Mucosal Immunology, 2022).
Everything starts from the microbiota
Thanks to previous studies we know that the health of the intestinal microbiota influences the health of the lungs, brain and heart. But there is also another link, albeit less studied. In fact, also the health of our skin depends on the bacteria that populate our gut. It is precisely this aspect that the scientists wanted to investigate, to understand if what we eat can help us prevent or treat skin allergies such as atopic dermatitis.
A high-fiber diet counteracts dermatitis
Scientists have developed research that has been performed in the laboratory on a population of mice. These mice were fed following a high-fiber diet, capable of supporting the microbiota and favoring those bacteria responsible for the production of short-chain fatty acids such as butyrate, which have an anti-inflammatory action. Then, the mice were exposed to allergens such as house dust mites. Dust mites easily penetrate the skin barrier, where they activate the immune system causing an allergic skin reaction. Well, the mice fed a high-fiber diet showed high protection against skin allergies. At this point, the scientists tried to give the mice directly butyrate, marked with isotopes, so that they could follow it inside the body. In this way it was possible to understand the protective process triggered by the microbiota. In fact, in a few minutes, butyrate reaches the skin where it increases the metabolism of keratinocytes, which are cells of the epidermis, by stimulating their maturation and the production of components to support a healthy protective skin barrier.
This study opens the door to future treatments, including topical ones, for atopic dermatitis based on butyrate. At the moment, it is certainly very useful, to counteract any form of skin allergy, to take care of the microbiota by trying to favor the good butyrate-producing bacteria. This is possible by taking fibers, such as resistant starch, a type of fiber with a powerful prebiotic action that nourishes good bacteria. These fibers are found in oats, barley, legumes, peas, cooked and then cooled carbohydrates, as occurs in pasta or rice salads.