Iron Deficiency and Iron Deficiency Anemia: A Comprehensive Overview of Established and Emerging Concepts.

Iron deficiency (ID) is the most prevalent micronutrient deficiency globally, affecting approximately one in four individuals, with a particularly high burden among children, women of reproductive age, and populations in low- and middle-income countries. It contributes significantly to the global burden of disease, with consequences ranging from impaired cognitive and motor development in children to increased risks during pregnancy, including low birth weight, preterm delivery, and maternal mortality, as well as reduced physical performance and quality of life in adults. ID often precedes iron deficiency anemia (IDA), though clinical and functional impairments-such as cognitive deficits, immune dysfunction, and fatigue-can occur even in the absence of anemia. Despite its widespread nature, challenges remain in precisely defining, diagnosing, and treating ID effectively. Advances in diagnostic tools allow for earlier detection, while novel therapeutic strategies, including updated oral dosing regimens and modern intravenous iron formulations, offer improved efficacy and tolerability. These approaches are particularly valuable in minimizing gastrointestinal side effects and enhancing patient adherence. This review is based on a comprehensive literature search conducted primarily through PubMed and Scopus, emphasizing studies published within the past 10-15 years. It is thematically structured to explore the epidemiology, health consequences, diagnostic complexities, and therapeutic developments related to ID. It highlights the multifactorial nature of ID and underscores the urgent need for early identification, targeted interventions, and updated clinical guidelines to reduce the long-term health and societal impacts of this preventable and treatable condition.