Occurrence, biological properties and potential effects on human health of β-casomorphin 7: Current knowledge and concerns

Crit Rev Food Sci Nutr. 2020;60(21):3705-3723. doi: 10.1080/10408398.2019.1707157. Epub 2020 Feb 7.


The genetic variant A1 of bovine β-casein (β-Cn) presents a His residue at a position 67 of the mature protein. This feature makes the Ile66-His67 bond more vulnerable to enzymatic cleavage, determining the release of the peptide β-Cn f(60-66), named β-casomorphin 7 (BCM7). BCM7 is an opioid-agonist for μ receptors, and it has been hypothesized to be involved in the development of different non-transmissible diseases in humans. In the last decade, studies have provided additional results on the potential health impact of β-Cn A1 and BCM7. These studies, here reviewed, highlighted a relation between the consumption of β-Cn A1 (and its derivative BCM7) and the increase of inflammatory response as well as discomfort at the gastrointestinal level. Conversely, the role of BCM7 and the effects of ingestion of β-Cn A1 on the onset or worsening of other non-transmissible diseases as caused or favored by still need proof of evidence. Overall, the reviewed literature demonstrates that the "β-Cn A1/BCM7 issue" remains an intriguing but not exhaustively explained topic in human nutrition. On this basis, policies in favor of breeding for β-Cn variants not releasing BCM7 and consumption of "A1-like" milk appear not yet sound for a healthier and safer nutrition.

Keywords: casomorphin; human health; milk; non-transmissible diseases; opioid peptide; β-casein.

MeSH terms

  • Animals
  • Caseins
  • Cattle
  • Endorphins*
  • Humans
  • Milk
  • Peptide Fragments


  • Caseins
  • Endorphins
  • Peptide Fragments
  • beta-casomorphin 7