Since the 1980s, scientists have observed an increase in the frequency ofasthma in all developed countries. In France, according to figures from the National Institute of Health (Inserm), it is estimated that 3 to 5% of adults are affected by this chronic inflammatory disease. In a study published by the journal Nature Medicine, Swiss researchers from the Center hospitalier universitaire vaudois, in Lausanne, noted that this increase coincides with a decrease in the consumption of fruits and vegetables.
They thus decided to carry out tests on mice presenting the same immune system as the human being. Separated into two groups, some mice were put on a diet low (0.3%) in fermentable fiber, similar to the Western diet, while the rest ate foods containing about 4% fiber. When faced with an extract of house mites, the mice of the first group developed a less severe allergic reaction than the others.
A chain reaction
The researchers explain these results by a chain reaction. Once ingested, the fibers enter the intestine, where they ferment in the presence of bacteria and are transformed into fatty acids. These acids are carried by the blood and influence the maturation of immune cells. In the presence of mites, these cells migrate from the bone marrow to the lungs, triggering a defensive reaction.
The study authors are also working on the role of diet in inflammations of the lungs such as chronic obstructive pulmonary disease, which is fast becoming the third leading cause of mortality in the world, indicates the site BBC News.
