The Impact of Children’s Dietary Habits on the Oral Microbiome: A Systematic Review

Background/Objectives: The oral microbiome plays a central role in maintaining oral health from early life, with childhood representing a critical period for its establishment and long-term stability. While many environmental factors influence this dynamic microbial ecosystem, diet is distinct in being both universal and highly modifiable. This systematic review aims to evaluate and synthesize current evidence regarding the impact and mechanisms of distinct dietary habits, food matrices, and nutritional components on the composition, diversity, and ecological resilience of the pediatric oral microbiome. Methods: A literature review aligned with PRISMA guidelines was conducted via digital searches on PubMed, ScienceDirect, and Cochrane databases (January 2015–December 2025). Search strategies combined MeSH terms and keywords targeting “Microbiota”, “Mouth”, “Child”, “Diet”, and “Oral health”. Results: From 1068 records identified, 16 relevant articles met the inclusion criteria. Dietary habits may influence taxonomic and functional profiles. Frequent consumption of sugar-sweetened beverages, sucrose-rich sodas, and sweet treats induces notable dysbiosis and enriches acidogenic/aciduric taxa. Conversely, protective food matrices, including probiotic-fortified dairy products, polyol-based sugar-free chewing gums (xylitol and maltitol), bovine milk, and bioactive-rich agents like green tea, actively suppress cariogenic pathways (specifically Streptococcus mutans) and support commensal, health-associated genera without disrupting overall microbial structures. Conclusions: Diet represents an important modifiable factor shaping the pediatric oral microbiome, capable of either driving dysbiosis or reinforcing symbiosis. Cultivating a microbiome-informed dietary approach early in childhood supports a resilient microbial architecture, offering a non-invasive, public health framework for long-term oral and systemic disease prevention.