Lactoferrin, a Natural Protein with Multiple Functions in Health and Disease

Lactoferrin is a multifunctional glycoprotein showing multiple biological properties (antimicrobial, antiviral, antioxidant, antigenotoxic, prebiotic, probiotic) that play an essential role in maintaining host physiological homeostatic condition by exerting immunomodulatory and anti-inflammatory activities. Thanks to these biological properties, lactoferrin has widely been studied as a therapeutic agent in gastroenteric diseases, neonatal sepsis and necrotizing enterocolitis, lung diseases, and COVID-19, showing very heterogeneous results based on the disease considered and the population studied. Since lactoferrin is one of the main components of neutrophils’ secondary granules, it has also been investigated as a potential disease-monitoring biomarker, especially for diseases in which inflammation is a key component. This narrative review offers updated and comprehensive insights into the available literature on lactoferrin biology, biological properties, and clinical utility.