Updated by: Arabinda Naik
Production of milk in the mammary gland is called lactation. At the puberty in female mammary glands begin to develop under the influence of oestrogen and progesterone. Secretion and storage of milk begins after birth within 24 hours under the influence of hormone prolactin (PRL) secreted by anterior pituitary gland. The ejection of milk is stimulated by the hormone oxytocin released from posterior lobe of pituitary gland. The first milk which comes from the mammary glands for 2 to 3 days is called colostrum. This is yellowish fluid that contains rich protein lactalbumin and lactoprotein but low in fat. Colostrum contains antibodies IgA that provide passive immunity to the newborn infant. Colostrum is considered your baby’s first immunization because it contains large quantity of an antibody called immunoglobulin A. as breast milk changes from colostrum to mature milk, the concentration of immune factors and antibodies decreases, but the volume of breast milk increases.
Human milk consists of water and organic and inorganic substances such as fat droplets, casein, lactose, mineral salts (sodium, calcium, potassium, phosphorous) and vitamins. Milk is poor in iron content. Vitamin C is present in an extremely low quantity in milk.