COMPOSITION OF BREAST MILK

Breast Milk Proteins

The composition of breast milk consists of protein, fat and lactose and other minerals and vitamins. The protein is present at lower level than the fat component in human milk.

Lactoferrin is an iron binding glycoprotein that exists in cow milk at the level of 0.2 mg per ml. Breast milk contains a higher concentration of lactoferrin at 0.1 to 0.2 g per 100 ml.

It shows antibacterial activity towards Escherichia coli thus warding of intestine, a potential predator. The bacteriostatic effect of lactoferrin may be explained by its ability to bind with iron and thereby preventing its availability to the iron requiring bacteria, there by preventing their growth.

Breast milk also contains a higher concentration of unsaturated Vitamin B12 binding protein, which competes with bacteria requiring Vitamin B12 for their growth.

A variety of enzymes including lactoperoxidase, xanthin oxidase and lysozyme also play important role in conferring immunity to the breast fed infants. Lysozyme in breast milk exerts its bactericidal effect by lysing the cell wall of the gram positive bacteria.

Lactoperoxidase – thiocyanate – hydrogen peroxide system (otherwise known as LP system) is another important system exhibiting antibacterial activity. Intestinal microflora of infant fed with breast milk consists almost bifidus bacteria. Glycoproteins and oligosaccharides present in appreciable quantities in breast milk or human milk promotes the growth of bifidus bacteria and thus confers immunity to the newborn against various diseases. It is an important constituent of breast milk.