Mouth and Stomach

• Digestion of complex carbohydrates begins with the release of amylase in saliva.
  
  Sugars come in many forms. Sucrose, better known as table sugar, has two sugar molecules, making it a disaccharide. Throughout the digestion process, enzymes break carbohydrates down into simpler sugars. Complex starches with several sugar molecules begin to pull apart from amylase enzyme in the mouth's saliva.
  
  Sucrose, and other disaccharides, pass through the stomach without their molecules breaking apart. Their molecules stay intact until they pass into the small intestine.
  
  

Small Intestines

• A simpler glucose molecule created from the more complex sucrose.
  
  The upper portion of the small intestine receives enzymes from the pancreas and the liver which act to tear the sucrose molecules apart. From the pancreas, another type of amylase breaks complex sugar molecules down into simpler disaccharides (sucrose, maltose and lactose). Enzymes from the liver designed specifically to turn each of these into a single molecule sugar (glucose) release further down in the small intestine. These enzymes include: sucrase, maltase and lactase. The name of the enzyme corresponding to the sugar it breaks down. Once the complex sucrose breaks down into glucose, the walls of the small intestine absorb it.
  
  

Liver

• The liver stores glucose made from sucrose until needed by the body.
  
  Sucrose broken down into glucose in the small intestine enters the blood stream through the intestinal walls. From there, it passes to the liver which holds the simple sugar until needed by the body. Should an excess of sugar consumption occur, the simple sugars get converted into fat for long term storage.