Lactose is the principal carbohydrate of milk. Lactose, the 12-carbon sugar present in milk, is broken down in the intestine to glucose and galactose (6-carbon sugars), both of which can be used as sources of energy and exist in two anomeric forms of which the α-form predominates.
It is the only sugar not found in plants, it is found in milk; hence, it is called milk sugar. Lactose gives milk and other dairy products a slightly sweet taste.
Most human infants are born with digestive enzymes necessary to split lactose into its two monosaccharide parts, glucose and galactose, so as to absorb it.
Lactose is probably the most troublesome disaccharides as some people lack of the enzyme lactase which splits the molecule glucose and galactose. These people may experience nausea, bloating, abdominal pain or cramping, diarrhea or excessive gas after drinking milk or eating lactose-containing products.
Lactose also facilitates the absorption of calcium and promotes the growth of beneficial bacteria in the intestines.
Disaccharide sugar of lactose
