Digestion is "the process by which food is converted into substances that can be absorbed and assimilated by the body." This is the definition of digestion given by the American Heritage Dictionary. Digestion happens in the alimentary canal, through the mechanical and enzymatic process of breaking down substances. In the end the substances such as fatty acids, simple sugars, amino acids are used by our cells for proper health.

Thus, healthy digestion begins in the mouth. Chewing is an integral part of the digestion process. The mechanical breakdown and enzymatic action happen in the mouth and are supported by chewing.

The function of the teeth is to tear the food into smaller bits and start the process of mechanical breakdown. The tongue muscles move the food as it is ground and crushed by the teeth into a soft mush. Chewing creates a large surface area and assures proper digestive action by enzymes produced in the stomach and intestine.

Improper chewing leaves large chunks of food going down the esophagus into the stomach and beyond. Since the stomach acid, pancreatic and intestinal enzymes work best on smaller particles, they cannot function properly if they have to work on larger chunks. The result is undigested foods, which breeds pathogenic bacteria and yeast, causing fermentation and rot. If it is allowed to continue, it can damage the intestinal lining causing irritation and inflammation.

While chewing the food, the teeth and tongue mix it with saliva. The saliva is the lubricant that helps to soften the food making it easy to go down the throat. However, if chewing is not done properly there is less saliva in the mouth, which leaves the food dry and makes swallowing difficult, as it irritates the delicate lining of the esophagus.

The first step in a chain of action which assures proper breakdown and assimilation of carbohydrates is the sugar and starch digestion by amylase, a starch digesting enzyme. This enzyme is contained in saliva, which is in short supply if chewing is not adequate.

Proper chewing, on the other hand, assures that carbohydrate rich foods are started on the path to digestion otherwise pathogenic yeast will act upon these foods when they enter the stomach and intestine. Yeast fermentation causes irritation as a side effect of gas, bloating and indigestion. Impaired carbohydrate digestion causes deficiency of simple sugars that our cells need for energy.

Saliva also contains lysozyme, an enzyme found in human tears and stomach secretions. Sir Alexander Fleming of pencillin fame discovered lysozyme in 1922. Lysozyme supports our healthy immune system by destroying the cell walls of bacterial organisms that may be found in the foods we eat. Chewing allows lysozyme to mix with the food in the mouth and act as a front line of defense against harmful bacteria.

To cut a long story short, human beings need to chew food properly for a healthy digestion. And, a healthy digestive system leads to the proper breakdown of carbohydrates and a healthy immune system.