Lactose, the milk sugar is present in most fresh dairy products. Lactose is also found in cheese, curd and yoghurt though the percentage of lactose might be lower than that in milk or fresh dairy products. Although milk and dairy products are the only natural source of lactose, it may be used as an additive in prepared foods like bread, baked goods, processed cereals, margarine, candies, biscuits.

Prescription drugs like antibiotics, oral contraceptives may also contain low amounts of lactose but only people with very low tolerance to lactose might get affected by these products.

Lactose is broken down into simple sugars, glucose and galactose by an enzyme called LACTASE that is produced by cells that line the small intestine. These simple sugars can be absorbed by our body and converted to energy. In case of people who do not make significant amounts of lactase enzyme the undigested lactose will move on to the colon where it is acted upon by the resident bacteria and can cause symptoms like bloating, diarrhea, flatulence or abdominal pain.

All infants can digest lactose present in mother’s milk (except in congenital alactasia). Post-weaning, depending on one’s genetic make-up the ability to digest lactose either persists through adulthood - LACTASE PERSISTENCE (LP) or substantially decreases - LACTASE NON-PERSISTENCE (LNP). This is an inherited character.

Clinical tests like Hydrogen Breath Test, Glucose Tolerance Test, Stool Acidity Test and Intestinal Biopsy are carried out to diagnose Lactose Malabsorption.

GENETIC TEST: This test determines the lactase persistence (LP) and the lactase non-persistence (LNP) status of an individual by determining the variant present in the genome.