Food Digestion Facts

Human digestion is a complex process, which turns the foods we eat into energy and nutrients that our bodies can use. Many internal organs work together to process our food, giving our bodies the fuel we need to survive.

The Mouth

• Digestion begins in the mouth, where the physical action of chewing breaks food down into smaller pieces. Saliva, secreted by salivary glands, uses special enzymes to extract starches and further dissolve food.

The Esophagus

• Once swallowed, food moves into the esophagus and down to the stomach. This happens through a process called peristalsis, whereby muscle contractions move food along as if on a conveyor belt. According to the National Digestive Diseases Information Clearing House, swallowing is the last part of the digestion process over which a person has conscious control. The body automatically manages everything that follows.

The Stomach

• The stomach uses muscle contractions to mix and break up food, while gastric acid secreted by the stomach lining breaks down proteins in the food. A special mucous coating ensures that gastric acid does not dissolve the stomach itself.

The Intestines

• From the stomach, food moves into the small intestine, where chemicals from the gallbladder and pancreas further break down carbohydrates, proteins and fats. The intestinal lining absorbs nutrients, which the bloodstream then carries to other parts of the body.

Waste

• Any undigested substances left over from the small intestine, such as fiber from food or leftover digestion cells, then move into the large intestine, to be expelled from the body as waste.