Nitrogen: A gaseous, nonmetallic element. Nitrogen is a
component of all proteins. Nitrogen is essential to the synthesis
of proteins the body must have, particularly nitrogen - containing
compounds or amino acids derived directly or indirectly from plant
food. The process of protein metabolism accounts for nitrogen
balance. When protein catabolism exceeds protein anabolism, a
negative nitrogen balance exists in the body. When protein
anabolism exceeds protein catabolism, a positive nitrogen balance
exists in the body.