Breastfeeding, Breastmilk Production and its Composition: A Gist.


In literal sense the word ‘breastfeeding’ means to feed the infant or the baby with the milk produced from the mother’s breast. Breastmilk is the best source of nutrition for an infant and it is infact the nature’s best baby food. According to World Health Organization breastfeeding is the normal way of providing young infants with nutrients they need for healthy growth and development.Exclusive breastfeeding is recommended upto 6 months of age with continued breastfeeding along with appropriate complementary foods upto 2 years of age and beyond.

Breastfeeding has well established benefits. According to the American Academy of Pediatrics (AAP), it is the preferred choice of feeding for all infants. Colostrum, the yellowish, sticky breastmilk produced at the end of the pregnancy is recommended by the WHO as the perfect food for the newborn and feeding should be initiated within the first hour after the birth.

How do breasts make milk?

Mammary glands in the breast produce breast milk. The regions in the gland where milk is produced is known as alveoli. These are small grape like sacs, surrounded by tiny muscles that squeeze them to push the milk produced into the ductules. Ductules are the small channels that carry the milk from alveoli to the main milk ducts.Milk ducts are the complex network of canals that carry the milk from alveoli and ductules straight to the young one. The size and number of milk ducts increase during pregnancy.


Fig: General view of breast anatomy

How does the process of breastmilk production take place?

The process of breastmilk production starts during pregnancy. When a woman conceives breasts undergo a number of transformation like for example they become tender, swollen, nipples and areolas get dark (the circle of skin surrounding the nipples).

Apart from the visible changes that take place as  mentioned above, a number of changes also take place inside the breast. Lactogenesis, the process of milk secretion from the mammary glands, can be divided into three main phases:

  1. Lactogenesis I
  2. Lactogenesis II
  3. Lactogenesis III

Lactogenesis I and II are hormonally driven. Phase I of lactogenesis starts halfway through the pregnancy and the production increases a manifold around 30-40 hours after the child birth, this embarks the second phase of Lactogenesis. During Lactogenesis I the developing placenta stimulates the release of hormones- progesterone and estrogen, which in turn stimulate the complex biological system for milk production. High levels of progesterone and estrogen during pregnancy inhibits the oozing out of the milk from ni[pples. At birth, the delivery of placenta results in sharp drop in progesterone levels and a simultaneous increase in prolactin hormone level that initiates the Lactogenesis II and oozing out of the milk.

After Lactogenesis II, the maintenance stage of the milk production commences which is marked as the Lactogenesis III. In this stage the milk synthesis is controlled at the breast and milk removal (emptying of the breasts) is the primary control mechanism for supply. Milk removal is driven by baby’s appetite and dependence on other sources of the food apart from mother’s milk.

Suckling of baby stimulates the brain to release more of prolactin hormone which is in turn stimulates the body to produce more milk. But gradually with time the prolactin response to the baby’s suckling reduces and this marks the return of menstural cycle of the mothers.

Breastmilk Composition

Breastmilk has been described as the nature’s best baby food. It is the source of all valuable and essential nutrients that are help an infant in its proper physical and mental growth and development. Breastmilk is a bioactive fluid and is dynamic in nature as its composition varies from colostrum to later stages of lactation and also it differs within feeds and mothers. These compositional differences are attributed to the maternal and environmental factors.

Breastmilk can be categorized into three main types:

  • Colostrum: It is the milk that oozes out from a mother’s breast just after the childbirth. It is a concentrated, creamy, high protein, low-fat substance.It is easily digestible and a rich source of immunoglobins, especially the secretory IgA, and disease fighting antibodies. It is more immunogenic rather nutritive.
  • Transitional Milk: It is the creamy milk that immediately follows colostrum. It is the mixture of colostrum and mature milk. It has high lipid content necessary for proper development of brain and is lactose rich that provides energy to the young one.
  • Mature Milk: It is produced from 20 days after childbirth and onwards. It is rich in fatty acid contents and the fat content increases as the feed progresses.

In general, the basic composition of breastmilk is as follows:

  • Free water
  • Proteins and vitamins
  • Essential fatty acids and long chain polyunsaturated fatty acids
  • Carbohydrates- lactose being the principle carb.
  • Immunoglobulins, IgA being the predominant one.

Besides the above-mentioned nutritional components, there are some non-nutritional components also found in breastmilk that are necessary for growth, development and providing the infant with disease resistance elements. These are:

  • Growth factors, eg. insulin-like growth factor, epidermal growth factor.
  • Essential enzymes like lysozyme.
  • Antimicrobial agents.

Relevance of breastfeeding

Breastfeeding is not only important for the baby but for the mothers also. Breastfeeding helps keep baby healthy, protect them from diseases, allergies, helps in easy digestion, babies have little or no problem of constipation, diarrhea, upset stomach. It is said that breastfed babies have higher IQ scores, lower risk for diabetes, obesity, respiratory and urinary tract infections and some childhood cancers.Breastfeeding helps mothers to get their uterus back to its pre-pregnant state faster, helps reducing their weight gained during pregnancy, reduces the risk of ovarian cancer and post-menopausal breast cancer and lowers their risk to develop Type 2 diabetes and osteoporosis.In fact, breastfeeding has proved to be an effective form of birth control. In Africa, breast feeding prevents an estimated average of four births per woman, and in Bangladesh it prevents an estimated average of 6.5 births per woman.(source: Natural Resource Defense Council). Above all the most important part of breastfeeding is that it strengthens the emotional ties between the mother and the her young one, thus, boosting her emotional quotient.

At the end, a piece of information: August 1-7 has been celebrated as the World Breastfedding Week (WBW)  in more than 120 countries including India. This event is being organised by WABA (World Alliance for Breastfeeding Action), WHO and UNICEF. For more information click on the link here:


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