EFFECTS OF RADIATION EXPOSURE ON THE HUMAN MICROBIOTA: UNDERLYING BIOLOGICAL MECHANISMS AND HEALTH CONSEQUENCES

Abstract

Radiation is a physical factor that, under certain conditions, can cause 
significant biological damage at the cellular and molecular levels. While low-level 
background radiation is a constant part of our environment and generally poses 
minimal risk, exposure to elevated levels—whether occupational, accidental, or 
therapeutic—can disrupt physiological systems and impair host–microbiome 
interactions. Recent studies have highlighted that radiation not only affects human cells 
directly, but also influences the composition, diversity, and functionality of the human 
microbiome, particularly in the gut. The microbiome plays an essential role in 
regulating immune responses, metabolic pathways, and maintaining epithelial barrier 
integrity. Ionizing radiation, through the generation of reactive oxygen species, DNA 
damage, and altered immune signaling, can lead to microbiota dysbiosis, reduced 
microbial diversity, and increased susceptibility to infection and inflammation. 
Moreover, changes in microbial populations under radiation stress may affect host 
resilience, recovery, and long-term health outcomes, including increased risk for 
malignancies and immune dysfunction. This paper explores the mechanisms by which 
ionizing and non-ionizing radiation affect microbial ecosystems within the human 
body and underscores the importance of preserving microbial balance in 
radiobiological research and medical applications. Understanding these interactions 
opens the door for microbiome-targeted interventions and bioprotective strategies in 
radioprotection.