The Role of Gut Microbiota in Food Allergies and the Potential Role of Probiotics for Their Treatment

The number of food allergies (FAs) is growing, particularly in industrialized countries, resulting in discomfort and a reduction in the quality of life of those who suffer from these allergies. Despite numerous epidemiological studies on FAs worldwide, the different approaches used constitute a limitation for an accurate prevalence of these disorders. The onset of FAs is multifactorial, since it depends on lifestyle, habitat, diet, and particularly on the diversity of gut microbiota. In fact, they occur in conditions of gut dysbiosis, an increase of the inflammatory state, an alteration of gut permeability, and an impairment of the resident immune cells, thus leading to a disruption and/or lack of tolerance towards food allergens. It is important to emphasize that the reduction of some bacteria leads to a decrease in their metabolite production, which, in turn, is crucial for the correct performance of immune responses and to ensure tolerance against allergens. Therefore, various strategies such as pre- and probiotic administration must be employed to avoid or prevent the onset of FAs.