What Is The Digestion System?

Need to Know
Issue No. 6: Food, Nutrition, and Access in Our Communities
Words - Diana McDonnell
Illustration - Alexandra Folino

Digestion is the way our bodies break down nutrients from food and drink. The entire digestive system is run and regulated by nerves and hormones. 

How Does Digestion Work?

  • The process of digestion begins in the mouth. Strong teeth are necessary to adequately chew and break down food in the mouth, and poor oral health is associated with an increased risk of infections, complications from heart disease, and uncontrolled blood sugar.

  • Food then moves from the mouth down through the esophagus to the stomach. Gastroesophageal reflux disease (GERD) is a disorder that causes acidic stomach juices, food, or liquids to travel backwards into the esophagus from the stomach. Acid reflux is common, and can be treated with over-the-counter drugs. 

  • In the stomach and small intestines, food mixes with digestive juices and bacteria to break down and aid the absorption of water and nutrients. After a large meal or one high in fat content, the gallbladder releases bile to assist in additional breakdown. Any waste products move towards the large intestine.

  • Stools form in the large intestine and are released by the rectum during a bowel movement. Irritable bowel syndrome (IBS) is a common disorder of the large intestine that can involve abdominal pain, constipation, and diarrhea. It is more common in women than men, and can severely impact one’s quality of life. Many treatment options exist.

What is Colon Cancer?

Cancer in the large intestine, or colon, often forms from small lesions or clumps of cells called polyps. Colon cancer screening is important because these lesions can often be removed before they turn into cancer. Generally it is recommended to start screening at age 50, but if you have a family history then you should start ten years earlier than the age the relative was diagnosed. The most accurate and effective screening is the colonoscopy, an exam where a tube is inserted in the rectum.