the capacity of the immune system to detect and neutralize pathogens, foreign substances, and aberrant cells
immune function operates through innate barriers (skin, mucosa, inflammation) and adaptive responses (antibodies, T-cells, immunological memory)
nutrition, sleep, stress, and microbiome composition modulate immune performance
many plants support immune function, including garlic, echinacea, elderberry, and astragalus, through antimicrobial and immunomodulatory secondary metabolites