Lactose

Lactose, or milk sugar, is found primarily in milk and most dairy products, but also in convenience food and medicine.

Lactose is processed by the enzyme lactase, which is released from the small intestine wall, and divided into the constituent sugars glucose and galactose, which can then be absorbed into the blood.

People who suffer from a congenital lactase deficiency have an inability to break down the milk sugar, which is called lactose intolerance. In some cases patients have to avoid lactose and gluten.