Gut colonising microbiota in early life as a crucial step in the acquisition of tolerance to food antigen in the first months of life

Abstract

Perinatal bacterial colonisation of the newborn's intestine is an essential key stage in the development of local immunity. The quality of its initiation on a still immature digestive mucosa and submucosa will eventually enable the acquisition of an immune balance between defence mechanisms and tolerance to antigenic epitopes of all kinds, firstly locally and then in the whole body. Failure to acquire this immune balance, favoured by complex epigenetic reactions linked to inadequate environmental modifications, can have a lasting impact on the development of subsequent general immunity. Exclusive and prolonged breastfeeding as stated by the World Health Organization (WHO) remains the only way of ensuring not only the quality of the colonising microbiota in the first few months of the infant's life, but also the quality of the development of this immune balance. This is linked to the completeness of human milk, rich in perfectly bioavailable constituents and complex, multiple immunomodulatory factors, which together enable it to be described as a functional food par excellence.