Protein-Amino Acid Metabolism Disarrangements: The Hidden Enemy of Chronic Age-Related Conditions

Nutrients. 2018 Mar 22;10(4):391. doi: 10.3390/nu10040391.


Proteins are macro-molecules crucial for cell life, which are made up of amino acids (AAs). In healthy people, protein synthesis and degradation are well balanced. However, in the presence of hypercatabolic stimulation (i.e., inflammation), protein breakdown increases as the resulting AAs are consumed for metabolic proposes. Indeed, AAs are biochemical totipotent molecules which, when deaminated, can be transformed into energy, lipids, carbohydrates, and/or biochemical intermediates of fundamental cycles, such as the Krebs' cycle. The biochemical consequence of hyper-catabolism is protein disarrangement, clinically evident with signs such as sarcopenia, hypalbuminemia, anaemia, infection, and altered fluid compartmentation, etc. Hypercatabolic protein disarrangement (HPD) is often underestimated by clinicians, despite correlating with increased mortality, hospitalization, and morbidity quite independent of the primary disease. Simple, cheap, repeatable measurements can be used to identify HPD. Therefore, identification and treatment of proteins' metabolic impairment with appropriate measurements and therapy is a clinical strategy that could improve the prognosis of patients with acute/chronic hypercatabolic inflammatory disease. Here, we describe the metabolism of protein and AAs in hypercatabolic syndrome, illustrating the clinical impact of protein disarrangement. We also illustrate simple, cheap, repeatable, and worldwide available measurements to identify these conditions. Finally, we provide scientific evidence for HPD nutritional treatment.

Keywords: amino acids; catabolism; inflammation; muscle wasting; protein metabolism; sarcopenia.

Publication types

  • Review

MeSH terms

  • Age Factors
  • Aging / metabolism*
  • Amino Acids / administration & dosage
  • Amino Acids / metabolism*
  • Animals
  • Dietary Proteins / administration & dosage
  • Dietary Proteins / metabolism*
  • Dietary Supplements
  • Energy Metabolism*
  • Humans
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / physiopathology
  • Nutritional Status
  • Protein-Losing Enteropathies / diet therapy
  • Protein-Losing Enteropathies / metabolism*
  • Protein-Losing Enteropathies / physiopathology
  • Proteolysis
  • Sarcopenia / diet therapy
  • Sarcopenia / metabolism*
  • Sarcopenia / physiopathology


  • Amino Acids
  • Dietary Proteins