The Relationship between the Infant Gut Microbiota and Allergy. The Role of and Prebiotic Oligosaccharides in the Activation of Anti-Allergic Mechanisms in Early Life.

The increase in allergy prevalence observed in recent decades may be a consequence of early intestinal dysbiosis. The intestinal microbiota is formed in the first 1000 days of life, when it is particularly sensitive to various factors, such as the composition of the mother's microbiota, type of delivery, infant's diet, number of siblings, contact with animals, and antibiotic therapy. Breastfeeding and vaginal birth favorably affect the formation of an infant's intestinal microbiota and protect against allergy development. The intestinal microbiota of these infants is characterized by an early dominance of , which may have a significant impact on the development of immune tolerance. is a species commonly isolated from the intestines of healthy breastfed infants and from human milk. This review outlines the most important environmental factors affecting microbiota formation and the importance of species (with a particular emphasis on ) in microbiota modulation towards anti-allergic processes. In addition, we present the concept, which assumes that infant formulas containing specific probiotic strains and prebiotic oligosaccharides may be useful in allergy management in non-breastfed infants.