Britannica Sources used in this answer

How does protein starvation cause the body to break down its own proteins?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

atrophy One example of atrophy is the progressive loss of bone that occurs in osteoporosis (normal bone shown on left; osteoporotic bone shown on right).

Under conditions of protein starvation, the body undergoes a process of generalized atrophy to sustain essential life functions. When dietary intake is insufficient to meet metabolic needs, the body breaks down its own structural proteins into their constituent amino acids.1

These amino acids are then utilized to provide energy and to help maintain the integrity and function of the most vital organs, such as the brain, heart, and kidneys. This catabolic process is a survival mechanism that prioritizes the preservation of these essential systems over other tissues, such as fat stores, the liver, and lymphoid tissues, which diminish more rapidly during periods of starvation.1

While the specific intracellular mechanisms for this protein turnover are not fully understood, it involves the action of intracellular enzymes that catalyze the splitting of peptide bonds to release the amino acids from the protein structure.2