Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance

Nutrients. 2019 May 15;11(5):1079. doi: 10.3390/nu11051079.


The results of twenty years of research indicate that the inclusion of collagen peptides in the diet can lead to various improvements in health. According to the current protein quality evaluation method PDCAAS (Protein Digestibility-corrected Amino Acid Score), collagen protein lacks one indispensable amino acid (tryptophan) and is therefore categorized as an incomplete protein source. Collagen protein displays a low indispensable amino acid profile, yet as a functional food, collagen is a source of physiologically active peptides and conditionally indispensable amino acids that have the potential to optimize health and address physiological needs posed by aging and exercise. The objective of this study was to determine the maximum level of dietary collagen peptides that can be incorporated in the Western pattern diet while maintaining its indispensable amino acid balance. Iterative PDCAAS calculations showed that a level as high as 36% of collagen peptides can be used as protein substitution in the daily diet while ensuring indispensable amino acid requirements are met. This study suggests that the effective amounts of functional collagen peptides (2.5 to 15 g per day) observed in the literature are below the maximum level of collagen that may be incorporated in the standard American diet.

Keywords: PDCAAS; collagen peptides; functional foods; protein; protein quality.

MeSH terms

  • Amino Acids
  • Collagen / chemistry*
  • Diet*
  • Dietary Proteins / administration & dosage*
  • Dietary Proteins / analysis
  • Food Analysis
  • Humans
  • Peptides / administration & dosage*
  • Peptides / chemistry
  • United States


  • Amino Acids
  • Dietary Proteins
  • Peptides
  • Collagen