Background: allergic diseases and, in particular food allergy (FA), have been identified as one of the major diseases in the world. The first 1000 days of life can be a “window of opportunity” or a “window of susceptibility” during which several factors can predispose children to FA development. Changes in gut microbiota composition, from pregnancy to infancy, could have a pivotal role in this regard: some bacterial genus such as Lactobacillus or Bifidobacterium seem to be protective from FA development, on the contrary Clostridium and Staphylococcus appear to be unprotective.
Methods: we conducted a research through the most recent literature (2013-2023), using Pubmed and Scopus as databases. We included English original papers, clinical trials, metanalysis and reviews. Case reports, series and letters have been excluded.
Results: during pregnancy, maternal diet can play a fundamental role in influencing gut microbiota composition of newborns. After birth, human milk can promote the development of protective microbial species by human milk oligosaccharides (HMOs), that play a prebiotic role. Also complementary feeding can modify gut microbiota composition.
Conclusions: the first two years of life are a critical period where several factors, in genetic predisposed children, can increase the risk of FA development.