Environmental epigenetics: new horizons in redefining biological and health outcomes

• Environmental factors strongly influence biological systems through epigenetic processes. • Epigenetic mechanisms provide plasticity and resilience but can also mediate disease risk when dysregulated. • Reversibility of epigenetic marks opens opportunities for targeted interventions and precision medicine. • Advances such as single-cell epigenomics and machine learning are essential to decode complex epigenetic signatures. • Ethical and policy considerations are critical as epigenetic screening and interventions expand. • Transgenerational epigenetic inheritance links ancestral trauma and social history to present-day health disparities. Environmental factors can have profound influences on biological systems, particularly through their effects on epigenetic processes. Epigenetics provides a powerful framework for understanding the regulation of gene expression through the interplay between genetic predispositions, inherited epigenetic marks, and lifelong environmental influences. This review proposes that even subtle epigenetic changes may initiate cascading effects on gene regulation and biological systems, ultimately contributing to significant phenotypic outcomes, including the modification of developmental trajectories, disease susceptibility, and adaptive responses. The reversible and adaptable nature of epigenetic modifications enables organisms to respond dynamically to a wide range of stimuli throughout their lifespan. Conversely, maladaptive epigenetic regulation can be associated with pathologies, including cancer, diabetes, neurodegenerative disorders, and adverse mental health outcomes. Thus, epigenetic markers represent a promising target for risk prediction, prevention and therapeutic intervention. In this narrative review, we discuss the wide-ranging implications of epigenetic theories underlying gene-environment interactions. Furthermore, we examine the evolving expectations of the scientific community and the public regarding epigenetic theories, which may shape future research directions and drive therapeutic innovation in health and disease. Epigenetic concepts are poised to bridge the gap between genetic predispositions and environmental influences, offering novel insights into complex biological processes and their outcomes.