Here's why:

* Amino Acids: Proteins are made up of long chains of smaller units called amino acids.

* Nitrogen is a key component of amino acids: Nitrogen is found within the amino group (-NH2) of each amino acid.

* Protein synthesis: When you eat proteins, your body breaks them down into amino acids. These amino acids are then used to build new proteins, which are essential for growth, repair, and various bodily functions.

Let me know if you have any other questions!