Lactoferrin is a protein which can be found in milk and other bodily fluids (e.g. tears, saliva). Its concentration in human colostrum is the highest, followed by human milk and cow milk. Its ability of binding to large quantities of iron provides protection against pathogens by making iron unavailable for pathogen growth.
Lactoferrin modulates the adaptive immune system and it can activiate the host immune response in various ways. Because of its immunological properties, as well as its antibacterial and antiviral activitiesIts, lactoferrin is sometimes taken as a supplement.