For centuries breast milk has been the only food for newborn infants and is the most natural way of providing infants with nutritional requirements for the first four to six months of life. Somewhere along the line women, doctors and society at large were persuaded to believe that tinned milk was as good as breast milk and came to acquire the status of all that is good for the infant and resulted in a decline in breastfeeding even among the poorer sections of society. In order to protect and promote breastfeeding, August 1 to August 7 is celebrated as World Breastfeeding Week every year.
Breast milk is complete food for an infant and no other milk or food can substitute it. It is convenient and costs nothing thereby contributing to food security and family self-sufficiency. As it does not require any preparation like tinned milk it can be readily fed to an infant on demand. Breastfeeding benefits both to the baby and mother.
The process of lactation is controlled by various hormones, the principle one being prolactin – which is secreted by the anterior pituitary gland and stimulates the breast to secrete milk. It is important to remember that the more the baby sucks the more milk will be produced by the breasts.
As the baby nurses the posterior pituitary gland produces the hormone oxytocin that makes the milk flow. If a mother thinks lovingly of her baby or hears her baby cry, this prolactin reflex is affected and she may feel a tingling sensation in her breasts and some milk may leak out, it then that she is ready to feed her baby.
For the first few days after delivery, the breasts secrete small amounts of a viscous lemony yellow fluid called colostrum that has a greater proportion of antibody rich proteins, but has lower fat and lactose content and hence lower energy content as compared to mature milk. Colostrum primarily has an anti-infective role and in a sense it is like an oral vaccine that protects an infant from infections. It also has a laxative effect that helps clear out the meconium and prepare the gut to digest and absorb mature milk. The irony is that although colostrum is anti-infective, many times infants are not breastfed for one or two days after birth and are given sweetened water instead. This custom should be avoided.
After the third or fourth day, the quantity of breast milk secreted starts to increase and the colour of the milk changes from lemony yellow to whitish grey and is known as mature milk. Mature milk is of two types. At the beginning of the feed the milk looks grey and watery. This is called foremilk and has a higher water, protein, lactose, vitamin and mineral content, but lower fat and hence energy content. Towards the end of the feed, the milk looks whiter and is called hindmilk. It is rich in fat and provides about half the energy of a breast feed and leaves a baby satisfied. It is essential to ensure that the baby consumes both the foremilk and hindmilk so that their need for energy and other nutrients are meet.
Fats are the major source of calories in breast milk and include essential fatty acids, long chain PUFAs, phospholipids and prostaglandin precursors that are essential for normal brain development.
Human milk is sweeter as it contains a higher content of lactose than any animal milk. Lactose along with fat contributes to the energy content of breast milk. It promotes the absorption of calcium and magnesium and also has an important role in the development of the central nervous system.
Breast milk contains a higher proportion of whey protein as compared to casein (the major protein in cow’s milk) and is easily digestible. It also contains a unique amino acid called taurine, which is essential for the development of an infant’s nervous system.
Maternal nutrient intake and nutritional status affects the vitamin content of breast milk. It contains the correct proportion of calcium and phosphorus, but has lower sodium content. The iron content of breast milk is low, but the iron is better absorbed as compared to iron from cow’s milk.
Breast milk contains adequate amounts of water to meet the baby’s need, even in hot and dry climates. Additional water or sugary drinks are not needed to quench a baby’s thirst.
To be continued…
(The writer is a consultant nutritionist with 17 years of experience, practising at Panaji and can be contacted on email@example.com)