Research conducted in Australia, the United Kingdom and Switzerland indicated that, in rats, eating fiber-rich foods strengthens the skin and reduces the symptoms and severity of allergic diseases such as atopic dermatitis, which affects about 20% of children worldwide. . The next step will be clinical studies in humans.
The experiments showed that, after ingestion, the fibers are fermented in the intestine by bacteria that produce butyrate, a type of fat capable of strengthening the outer layer of the skin, preventing dehydration and the penetration of allergy-causing agents, such as mites and microbes.
That’s because the substance accelerates the metabolism of keratinocytes, cells responsible for generating proteins and fats necessary to keep the skin healthy.
Atopic dermatitis, an incurable chronic inflammatory disease, is characterized by dryness and wounds on the skin, which greatly affect the quality of life of patients.
Treatment involves moisturizing creams and corticosteroid ointments. Immunotherapy has been tested to combat the condition.
To Folha, one of the main authors of the research, Ben Marsland, from Monash University, in Melbourne (Australia), says that “there is great potential in the application of this substance [butirato] on the skin, with direct effects where the treatment is needed”. “It’s a safe substance that can be tested in clinical trials very quickly,” he says.
The study also had the participation of scientists from the University Hospital of Lausanne (Switzerland) and the University of Manchester (United Kingdom). The results were published in the journal Mucosal Immunology in early June.
The researchers fed groups of mice a high-fiber diet and others a low-fiber diet. The mice had skin inflammation in the back region similar to chemical-induced atopic dermatitis.
In addition, they administered, orally, butyrate associated with a radioactive substance that made it possible to track the path and time that the substance travels in the body, being detected in the skin of the rats 45 minutes after ingestion.
Mice fed a high-fiber diet and those given butyrate had reduced damage to the inflamed area, compared to mice fed a low-fiber diet. The end result was a decrease in inflammatory symptoms and an increase in the skin’s ability to retain water.
It was also verified, in the animals treated with butyrate, a reduction in the thickness of the skin and less presence of immune system cells in the injured region.
Another difference observed was the decrease in itching in the inflamed area, the main symptom of atopic dermatitis.
Butyrate has been found to reduce the production of amphregulin, a substance that causes nerves to sprout in the affected skin, leading to intense itching.
For Jorge Kalil Filho, professor of immunology and allergy at the USP School of Medicine, the experiment showed, precisely, at the molecular level, the path that a nutrient takes and its direct function in the skin.
Marsland of Monash University points out that while people already buy butyrate supplements, “we don’t know how much and how often to use them for health benefits.” “More butyrate is not necessarily better.”
Butyrate supplements and other substances produced by bacteria are already on the market — the so-called post-biotics, which have shown promise in studies to combat a number of diseases.
However, its exact mechanisms and effectiveness in some situations are not yet known.
Postbiotics differ from probiotics, which contain live microorganisms and are present in foods such as yogurt, kefir, and kombucha.
Prebiotics, on the other hand, serve as food for these beneficial microorganisms and are found in bananas, garlic and whole grains.
Also according to the authors of the research, allergic diseases have increased in recent decades, affecting almost a third of the world’s population.
The causes are environmental and behavioral changes associated with an unbalanced, low-fiber diet.
These allergies can progress to different conditions throughout life. Atopic dermatitis in childhood, for example, can progress to allergic rhinitis and asthma in adults. This is the so-called “atopic march”, which affects approximately 30% of people with the disease.
Research such as Marsland’s, which investigates the role of microorganisms in the human intestine —the microbiome—, is on the rise in the biomedical field around the world, including Brazil. They have shown that the alteration of this environment in the body is related to neurological and psychiatric diseases (such as autism, schizophrenia, depression, Parkinson’s and Alzheimer’s), intestinal, degenerative and autoimmune diseases.
“The intestinal microbiota plays the role of an extra organ in the body, it is so important for our health”, says Ricardo Barbuti, a gastroenterologist at the Hospital das Clínicas at USP who researches the influence of the microbiome on gastrointestinal diseases.
According to professor Jorge Kalil Filho, from USP, however, the application of the results has not been consolidated among physicians.
“I don’t believe that in everyday medical practice changes in diet are already prescribed for those who have depression, for example. Treatments are still centered on medication and therapy.
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