The Science of Resistant Starch (RS) Starch is a complex carbohydrate made of glucose units. During digestion, enzymes—mainly amylase from saliva and the pancreas—break starch into smaller sugars, ultimately glucose, which is absorbed from the small intestine into the bloodstream. However, not all starch is digested this way. The fraction that escapes digestion in the small intestine is known as resistant starch (RS) . As the name suggests, resistant starch “resists” enzymati