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Author(s): Nancy Moreno, PhD, and Barbara Tharp, MS.

The Science of Digestion

In this activity, students learned about the following properties of food.

  • Food must be broken down, both physically and chemically, into smaller units before it can be used by the cells within an organism. In humans, digestion begins in the mouth, where pieces of food are mechanically broken, by chewing, into smaller pieces. In addition, saliva mixes with the food and begins to break it down. After food is swallowed, other components of the digestive system—stomach, small intestine, large intestine, liver and  pancreas—continue the process of making food available for use by cells in the body.
  • Digestion is the process of breaking food down.
  • Special chemicals in the body break food molecules into smaller units. Molecules such as saliva in our mouth, enzymes in our stomach, bile released from the liver, and pancreatic fluid from the pancreas, help break down the fats, proteins and carbohydrates from food into smaller molecules.
  • Proteins—found in all meats, dairy products and vegetables (especially peas and beans)—are important for muscle and cell growth and repair. Proteins and their building blocks (amino acids) are vital to every cell in the body. Because humans are not able to make their own amino acids, they must consume at least a small amount of protein (equivalent to about 4 ounces of chicken white meat) each day. During digestion, proteins are broken down into the different amino acids of which they are made. The body then builds new proteins from these amino acids. You might say that amino acids are recycled! 

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932