Breast milk provides the developing neonate with valuable maternal IgA (73), immunomodulatory and anti-infective molecules such as lactoferrin (74), beneficial modulation of TLR-4 signaling (75), and specific healthy microbes such as Lactobacillus (see section on “Understanding the pathophysiology of NEC and the rationale for prophylactic use of probiotics”), packaged alongside the resources that these microbes need to succeed (see section on “Advances in prebiotics, synbiotics, and postbiotics”). Here, TLR4 is linked to necrotizing enterocolitis.