Physiological Basis of Immune Function Among Geriatric Population and Nutrition: A Narrative Review

The gradual decline of immune function associated with ageing is termed immunosenescence. This review explores the geriatric physiological change in immune system dynamics. Innate immunity changes due to ageing include reduced chemotaxis, phagocytosis, impaired neutrophil extracellular trap formation, and shifts in macrophage and dendritic cell functions. Adaptive immunity changes are marked by thymic involution, reduced naïve T and B cell output, and accumulated memory and senescent lymphocytes, diminishing immune diversity and efficacy. These immunological factors contributed to low-grade inflammation (inflammation), increased susceptibility to infections, and reduced vaccine responses. Other conditions like gut dysbiosis and persistent infections like Cytomegalovirus also cause immune exhaustion, resulting in an increased risk of respiratory and urinary tract infections and chronic metabolic and neurodegenerative diseases. Understanding these complex interactions in ageing and related nutritional deficiencies induced by immune system impairment is vital for addressing age-related health challenges in the elderly population.