Which protein found in breast milk inhibits the growth of iron-dependent bacteria?

Lactoferrin is a glycoprotein that is abundantly found in breast milk and has unique properties that contribute to the health of the neonate. One of its primary roles is to bind iron, thus creating a condition in which iron-dependent bacteria, such as certain pathogenic strains, have reduced access to this essential nutrient, thereby inhibiting their growth. This mechanism not only helps maintain a balanced microbial flora in the infant’s gut but also provides an important defense against infections.

Casein and whey are proteins that support the nutritional needs of the newborn, but they do not have the specific antibacterial properties attributed to lactoferrin. While immunoglobulin A (IgA) plays a crucial role in the immune response and helps protect the intestines from infections, it does not specifically inhibit the growth of iron-dependent bacteria. Therefore, lactoferrin stands out for its unique ability to restrict bacterial growth via iron chelation.