A nurse is reinforcing teaching about colostrum with a new mother who is breastfeeding. The mother asks. "Why is colostrum so important for baby?" Which of the following responses should the nurse make?

Rationale: A. "Colostrum provides vitamin K which is an essential nutrient for newborns." While vitamin K is essential for clotting, it is not found in sufficient amounts in colostrum. This is why newborns routinely receive a vitamin K injection shortly after birth, rather than relying on breast milk as a source. B. "Colostrum provides many important antibodies that the newborn lacks." Colostrum is rich in immunoglobulins, especially IgA, which help protect the newborn from pathogens by providing passive immunity. These antibodies line the infant's gastrointestinal tract and offer critical defense during early life. C. "Colostrum contains iron, which is important for a newborn's brain development." Although breast milk contains iron, colostrum is not a major source of it. Newborns are typically born with adequate iron stores to last several months, and the primary role of colostrum is immune protection, not iron supplementation. D. "Colostrum contains a natural diuretic that stimulates the newborn to void." While colostrum has a laxative effect that helps the newborn pass meconium, there is no known diuretic component. Its primary importance lies in delivering antibodies and coating the GI tract to reduce infection risk.