From Food to Function: Cross-Kingdom Transfer and Regulatory Potential of Dietary microRNAs Highlighted by Breast Milk

Dietary microRNAs (miRNAs) constitute a novel nexus among nutrition, gene regulation, and human health. Accumulating evidence indicates that miRNAs ingested with food can traverse the gastrointestinal barrier, enter systemic circulation, and modulate gene expression through gene-silencing mechanisms in critical metabolic pathways of mammals. These observations have driven growing interest in elucidating their bioavailability, molecular stability, and physiological relevance. In this review, we provide a systematic analysis of dietary miRNAs, with particular emphasis on plant-derived species and those present in breast milk, evaluating controversies and their potential implications for human health and disease. Breast milk is highlighted as a key vehicle for miRNA-mediated communication in early life, integrating maternal, environmental, and infant signals. Drawing on these insights, we identify major challenges in dietary miRNA research and propose strategies to address them, establishing a structured framework to guide future studies. Finally, we highlight the biotechnological potential of dietary miRNAs in promoting nutritional approaches to advance human health.