What is lactose?

Lactose is the natural sugar found in milk and dairy products.

Lactose is made up of two simpler sugars, glucose and galactose, joined together. On average, plain milk naturally has about 5g of lactose per 100ml.

Lactose provides a source of energy for the body. To break lactose down, your body uses an enzyme called lactase, which is produced in the small intestine. Lactase splits lactose into glucose and galactose so your body can absorb them and use them for energy.

The amount of lactose varies between dairy products. Milk generally contains the most lactose, while yoghurt often has less because the live cultures used to make yoghurt break down some of the lactose during fermentation. Hard cheeses like parmesan and cheddar also contain a very small amount of lactose because most of it is removed during the cheesemaking process.