Digestive enzymes break down big food molecules into smaller, soluble components that can be absorbed through the walls of the digestive system into the blood stream.
Carbohydrase enzymes break carbohydrates down into simple sugars.
Protease enzymes break proteins down into amino acids.
Lipase enzymes break lipids down into fatty acids and glycerol.
Enzymes are also used to synthesise carbohydrates, proteins and lipids from their smaller components.