Your body, mainly the gut, breaks down all the food you eat into small pieces, like a blender processing everything. With milk, cheese, and yogurt, it’s the same.

But there is a special helper that breaks down lactose (a type of sugar found in milk) into tiny pieces. This helper is an enzyme called lactase.

It works like a pair of scissors that cuts a paper foil into little bits. Some people don’t have this help, or it doesn’t work well. Then, they develop lactose intolerance. They can feel sick, with a bellyache, nausea, and diarrhea.

To feel better when eating their favorite milk products, they can take medicine with extra helpers (lactase) or choose lactose-free food.