What causes lactose intolerance?

It's becoming a more common topic of discussion. According to BUPA.co.uk, “around one in every 10 older children and adults are thought to have lactose intolerance”. It might be thought of as a disease by some, but in fact it’s quite the opposite. Lactose intolerance is due to a natural process, which sees people’s bodies produce less of an enzyme called lactase as they age.

Lactose is a natural sugar found in all mammalian milks, including cow's, sheep's, mare's, and even human breast milk. It's made up of galactose and glucose, two types of simple s...