Colostrum

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Colostrum (from Latin, of unknown origin) is the first form of milk produced by the mammary glands of humans and other mammals immediately following delivery of the newborn.^[1] Animal colostrum may be called beestings, the traditional word from Old English dialects.^[2] Most species will begin to generate colostrum just prior to giving birth. Colostrum contains antibodies to protect the newborn against disease and infection, and immune and growth factors and other bioactives that help to activate a newborn's immune system, jumpstart gut function, and seed a healthy gut microbiome in the first few days of life. The bioactives found in colostrum are beneficial for a newborn's health, growth and vitality.^[1] Colostrum strengthens a baby's immune system and is filled with white blood cells to protect it from infection.

At birth, the environment of the newborn mammal shifts from the sterile conditions of the mother's uterus, with a constant nutrient supply via the placenta, to the microbe-rich environment outside, with irregular oral intake of complex milk nutrients through the gastrointestinal tract.^[3] This transition puts high demands on the gastrointestinal tract of the neonate, as the gut plays an important part in both the digestive system and the immune system.^[4] Colostrum has evolved to care for highly sensitive mammalian neonates and contributes significantly to initial immunological defense as well as to the growth, development, and maturation of the neonate's gastrointestinal tract by providing key nutrients and bioactive factors. Bovine colostrum powder is rich in protein and low in sugar and fat.^[5][6] Bovine colostrum can also be used for nonorganic failure to thrive in children and acute non-steroidal anti-inflammatory drug-induced increase in intestinal permeability in males^[7] and can boost a neonate's immunity.^[8]

Colostrum also has a mild laxative effect, encouraging the passing of a baby's first stool, which is called meconium.^[9] 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^{[citation needed]} from the infant's body, and which is often responsible for jaundice.

Research on possible health benefits and medical applications of bovine colostrum is ongoing. As of January 2025, there is no accepted medical use of bovine colostrum to treat any condition.