Lactose in the main carbohydrate in breast milk. Oligosaccharides (there are 131 in breast milk and only 10 in cow's milk), galactose and fructose are also at hand. Oligosaccharides help the growth of lactobacillus bifidus, which boosts intestinal movement and deters the growth of pathogens and also help to block antigen attachment to the gastrointestinal tract.
Lactose is made in the mammary gland. It strengthens the absorption of calcium and metabolizes into galactose and glucose, which supply energy for growth. Lactose is powerful in managing the volume of milk. It is also altered by diet.

