Enzymes can be divided into three groups. Enzymes are catalysts, an integral part of the digestive process. They initiate or speed up a reaction. These enzymes come from two sources, those found in the food itself, and those produced in the body. When food is ingested, enzymes are released in the mouth (ptyalin) that aid in breaking open carbohydrate cell walls. As the food progresses through the digestive tract, other enzymes are released. The ultimate breakdown of food occurs in the small intestine assisted by the release of pancreatic enzymes. When raw food is ingested, enzymes present within the food are released, thereby assisting the body’s digestive processes in breaking down the food into its simplest components for utilization within the body. However, if food is cooked or processed, these “food” enzymes are inactivated, and therefore the burden of digestion is left to the body’s own enzymes, mostly those produced by the pancreas. And often, incompletely digested food is passed into the colon taking vital nutrients with it, sometimes causing intestinal upset.