How do humans digest food?
What is digestion?
There are three parts to digestion:
- Breaking food down into smaller and smaller pieces
- Absorbing the things our bodies need
- Getting rid of the waste our bodies can’t use
How do we digest food?
For humans, cooking food is a way of making it easier to digest. Imagine trying to eat hard, raw rice or potatoes!
Teeth break food into smaller pieces and grind it up. Water in saliva helps turn food into a soft paste that is easier to swallow. Saliva also contains chemicals called enzymes. These break the food down into smaller molecules.
When we swallow, food travels down the throat through the oesophagus to the stomach.
The stomach churns food around. More enzymes and acids break the food down even more. The acid can kill microorganisms that might make you ill. After about four hours in the stomach,food moves into the small intestine.
The walls of the small intestine are able to absorb the proteins, carbohydrates, fats and vitamins we need. These pass into your bloodstream and are carried around the body to where they are needed.
Next is the large intestine which mostly absorbs water. This leaves waste called faeces that your body can’t absorb.
This is stored in the rectum until you are ready to push it out of your anus when you go to the toilet.