Changes in gut microbiota diversity and composition during feeding transitions in infants: A scoping review

Infants experience significant changes in gut microbiota during the first year of life as they transition from exclusive milk consumption to solid foods. The purpose of this study is to explore how dietary changes in infancy influence gut microbiota composition and diversity. A scoping review was conducted using databases including PubMed, Web of Science, Ovid Medline, Science Direct, and ProQuest. English-language studies published between 2003 and 2023 were included if they focused on mothers and caregivers with children aged 0 to 23 months involved in Infant and Young Child Feeding practices. A total of 561 studies were identified, with 15 articles included for data extraction. Significant differences in gut microbiota diversity related to feeding practices were observed. Infants who were exclusively breastfeding (EBF) exhibited lower phylogenetic diversity (5.8 ± 1.3, P < 0.05) compared to non-EBF infants (6.4 ± 1.8, P < 0.05). The EBF infants showed significantly (P < 0.05) higher levels of beneficial bacteria, such as Bifidobacterium, while non-EBF infants had elevated levels of potentially pathogenic genera, including Bacteroides and Clostridium. Additionally, earlier introduction of complementary foods was associated with increased alpha diversity (mean difference = 0.40, 95% CI: 0.25, 0.55), and dietary factors such as total energy intake, carbohydrate, and fiber significantly correlated with gut microbial diversity (P < 0.05). These results imply that the type of feeding, timing of introduction, and type of food intake during complementary feeding have a significant impact on the infant's gut microbiota diversity and composition. Future research could explore the long-term implications of these early dietary exposures on metabolic function and immune system health.