Proteins and other nitrogen-based compounds are in a constant state of being degraded and re-synthesized in the body. Protein turnover is a concept that define the continual renewal or replacement of protein in the body. In brief, protein turnover is defined by the balance between protein synthesis and protein degradation. However, different types of proteins have very different turnover rates. Likewise, several times more protein is turned over daily (used) within the body than is ordinarily consumed (replaced). As a result of losses, a continuous supply of dietary amino acids is required to replace these losses, even after growth has ceased (see: Wikipedia).