BREASTFEEDING AND CHILD HEALTH: INFLUENCE ON ORAL MICROBIOTA, IMMUNOLOGICAL MARKERS, AND SALIVARY PARAMETERS ASSOCIATED WITH ORAL HEALTH

Abstract

Breastfeeding continuously exposes the infant's oral cavity to microorganisms, oligosaccharides, antimicrobial proteins, immunoglobulins, and other bioactive components potentially capable of modulating the microbial ecology and immunity of the oral mucosa. This integrative review aimed to critically analyze the evidence on the association between breastfeeding, oral microbiota, immunological markers, and salivary parameters related to infant oral health. The question was constructed using an adapted PEO/PICO strategy. Primary studies indexed in PubMed/MEDLINE and relevant literature retrieved from SciELO were identified and individually verified. The synthesis shows that the feeding pattern is associated with the composition of the oral microbiome, especially in the first months of life: several studies observed lower initial diversity and differences in the abundance of Streptococcus, Veillonella, Prevotella, Lactobacillus, Bifidobacterium, and other taxa between breastfed and formula-fed infants. Recent studies also demonstrate associations between breastfeeding characteristics, human milk oligosaccharides, lactoferrin and other milk components, and specific aspects of the oral microbiome, although some of these effects are small and do not establish causality. Evidence on salivary immunity is less numerous: classic studies suggest faster maturation of secretory IgA in breastfed infants, while a recent study found higher oral IL-17 in the formula-fed group. Biochemical interactions between human milk and neonatal saliva constitute an additional plausible mechanism of innate defense. However, heterogeneity in the definition of exposure, age, sampling technique, sequencing, control of confounders, and introduction of complementary foods limits comparisons and causal inferences. It is concluded that breastfeeding is associated with measurable differences in microbial ecology and in certain components of infant oral immunity, particularly in early life, but the long-term clinical relevance of these differences for caries and other oral outcomes remains insufficiently established.