Alternate Names : Human Milk, Mother's Milk
A woman's body produces breast milk after the birth of an
infant due to changes in hormonal patterns. The birth triggers the release of
hormones that cause the body to produce breast milk.
During the first few days after birth, a woman's body
produces a fluid called colostrum. Colostrum is high
in protein, zinc, and other minerals. It contains less fat, carbohydrates,
and calories than breast milk. Between the third and sixth day after
birth, colostrum changes to a transitional form of breast milk. During
this time, the amount of protein and immune factors in the milk gradually
decrease, while fat, lactose, and calories in the milk increase.
By the tenth day after birth, the mother produces mature
breast milk. Colostrum and human milk are both rich in antibodies and have
anti-infective factors. These help protect the newborn infant from
viruses and bacteria that the infant was exposed to in the birth canal.
They also help to protect the infant's immature gut from infection.
Breast milk also promotes the growth of bacteria in the digestive
tract. This bacteria is helpful rather than harmful and assists with the
digestion of food. In addition, breast milk contains immune factors
that help an infant fight infection. These immune factors also help
prevent the infant from developing possible food allergies.
Most women have similar nutrients in their breast milk, but
this may vary slightly because of what a woman eats and
how her body produces the breast milk. If the mother does not eat a healthy diet,
she may produce less milk that contains smaller quantities of nutrients.
Women who are breastfeeding should eat 500 calories per day more
than her usual healthy range. This
helps her make sure she provides the infant with the
quality and quantity of milk needed. Milk content can also change
from one time of the day to another, and from the beginning of a
breast-feeding session to the end of a session. The nutrients in
breast milk also change from the early months of infancy to the later
months of infancy. These changes match the changing nutritional
needs of the growing infant.
The proteins in human breast milk are mostly whey
and casein. Cow's milk contains more casein, and
human breast milk contains more whey. Whey is more easily tolerated
by an infant's digestive system.
The fat in human breast milk is easily absorbed by an
infant's digestive system. An enzyme called lipoprotein lipase helps
an infant absorb the fat in breast milk. A mother's breast milk contains
essential fats. It also contains cholesterol.
needed by infants to make tissues in the nervous system. The amount
of fat in breast milk rises greatly at the end of a breastfeeding
session. This may be nature's way of making an infant feel full and
Breast milk contains large amounts of lactose,
which is a carbohydrate. Lactose is used in tissues of the brain and spinal
cord, and it provides the infant with energy. Bacteria in the infant's intestines
feed on lactose and produce B vitamins. Lactose may also help the infant
absorb essential nutrients such as calcium, phosphorus, and magnesium.
Human breast milk contains only a small amount of
iron, but the iron in breast milk is easily absorbed.
Fifty percent of the iron in human breast milk is absorbed
compared with only 4 to 10 percent of the iron in cow's milk or commercial
Breast milk contains all the vitamins an infant needs for good
health. The actual amount of each vitamin can vary, depending on a
woman's diet and genetic makeup.