Is it possible to devellop a milk intolerance later in life?

Milk intolerance : Milk intolerance can develop at any age, and is most often due to a deficiency of lactase, the enzyme the body uses to digest milk sugar, or lactose. Babies make the enzyme well, but in many parts of the world, adults don't. Without the enzyme, the sugar remains inside the gut and can't be absorbed, and causes fluid to remain there too, leading to diarrhea.