Kid's Health

You probably know you need to eat protein, but what is it? Many foods contain protein (say: pro-teen), but the best sources are beef, poultry, fish, eggs, dairy products, nuts, seeds, and legumes like black beans and lentils.

Protein builds, maintains, and replaces the tissues in your body. (Not the tissues you blow your nose in! We mean the stuff your body's made up of.) Your muscles, your organs, and your immune system are made up mostly of protein.

Your body uses the protein you eat to make lots of specialized protein molecules that have specific jobs. For instance, your body uses protein to make hemoglobin (say: hee-muh-glow-bin), the part of red blood cells that carries oxygen to every part of your body.

Other proteins are used to build cardiac muscle. What's that? Your heart! In fact, whether you're running or just hanging out, protein is doing important work like moving your legs, moving your lungs, and protecting you from disease.

All About Amino Acids

When you eat foods that contain protein, the digestive juices in your stomach and intestine go to work. They break down the protein in food into basic units, called amino acids (say uh-mee-no a-sids). The amino acids then can be reused to make the proteins your body needs to maintain muscles, bones, blood, and body organs.

Proteins are sometimes described as long necklaces with differently shaped beads. Each bead is a small amino acid. These amino acids can join together to make thousands of different proteins. Scientists have found many different amino acids in protein, but 22 of them are very important to human health.

Of those 22 amino acids, your body can make 13 of them without you ever thinking about it. Your body can't make the other nine amino acids, but you can get them by eating protein-rich foods. They are called essential amino acids because it's essential that you get them from the foods you eat.