Colostrum is the breast milk secreted shortly before and for a few days after childbirth. It is sometimes referred to as first milk or pre-milk.
Newborns have very immature digestive systems, and colostrum delivers its nutrients in a very concentrated low-volume form. It has a mild laxative effect, encouraging the passing of the baby’s first stool, which is called meconium. This clears excess bilirubin, a waste-product of dead red blood cells, which is produced in large quantities at birth due to blood volume reduction from the infant’s body and helps prevent jaundice. Colostrum is known to contain immune cells (as lymphocytes) and many antibodies such as IgA, IgG, and IgM. These are some of the components of the adaptive immune system. In preterm infants some IgA may be absorbed through the intestinal epithelium and enter the blood stream though there is very little uptake in full term babies. This is due to the early “closure” of the intestinal epithelium to large molecule uptake in humans unlike the case in cattle which continue to uptake immunoglobulin from milk shortly after birth. Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin, lysozyme, lactoperoxidase, complement, and proline-rich polypeptides (PRP).
Colostrum is very rich in proteins, vitamin A, and sodium chloride, but contains lower amounts of carbohydrates, lipids, and potassium than mature milk. The most pertinent bioactive components in colostrum are growth factors and antimicrobial factors. The antibodies in colostrum provide passive immunity, while growth factors stimulate the development of the gut. They are passed to the neonate and provide the first protection against pathogens.
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Colostrum. (2016, September 21). In Wikipedia, The Free Encyclopedia. Retrieved 19:42, September 21, 2016, from https://en.wikipedia.org/w/index.php?title=Colostrum&oldid=740551263