· US National Library of Medicine, National Institutes of Health
Comparative evaluation of cow β-casein variants (A1/A2) consumption on Th2-mediated inflammatory response in mouse gut. June 2014
Animal Biochemistry Division, National Dairy Research Institute, Karnal, 132001, Haryana, India, firstname.lastname@example.org.
Study Conclusion: It is reasonable to conclude that consumption of A1 "like" variants of β-casein induced inflammatory response in gut by activating Th2 pathway as compared to A2A2 variants. The present study thus supports the purported deleterious impacts of consumption of A1 "like" variants of β-casein and suggests possible aggravation of inflammatory response for etiology of various health disorders.
· Comparative effects of A1 versus A2 beta-casein on gastrointestinal measures: a blinded randomised cross-over pilot study. September 2014
1School of Public Health, Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia.
2Agricultural Management Group, Lincoln University, Christchurch, New Zealand.
3A2 Dairy Products Australia Pty Ltd., Melbourne, Victoria, Australia.
Study Conclusion: These preliminary results suggest differences in gastrointestinal responses in some adult humans consuming milk containing beta-casein of either the A1 or the A2 beta-casein type, but require confirmation in a larger study of participants with perceived intolerance to ordinary A1 beta-casein-containing milk.
· Polymorphism of bovine beta-casein and its potential effect on human health. 2007
Department of Animal Genetics, University of Warmia and Mazury, M. Oczapowskiego 5, 10-718 Olsztyn, Poland. email@example.com
Review:Proteins in bovine milk are a common source of bioactive peptides. The peptides are released by the digestion of caseins and whey proteins. In vitro the bioactive peptide beta-casomorphin 7 (BCM-7) is yielded by the successive gastrointestinal proteolytic digestion of bovine beta-casein variants A1 and B, but this was not seen in variant A2. In hydrolysed milk with variant A1 of beta-casein, BCM-7 level is 4-fold higher than in A2 milk. Variants A1 and A2 of beta-casein are common among many dairy cattle breeds. A1 is the most frequent in Holstein-Friesian (0.310-0.660), Ayrshire (0.432-0.720) and Red (0.710) cattle. In contrast, a high frequency of A2 is observed in Guernsey (0.880-0.970) and Jersey (0.490-0.721) cattle. BCM-7 may play a role in the aetiology of human diseases. Epidemiological evidence from New Zealand claims that consumption of beta-casein A1 is associated with higher national mortality rates from ischaemic heart disease. It seems that the populations that consume milk containing high levels of beta-casein A2 have a lower incidence of cardiovascular disease and type 1 diabetes. BCM-7 has also been suggested as a possible cause of sudden infant death syndrome. In addition, neurological disorders, such as autism and schizophrenia, seem to be associated with milk consumption and a higher level of BCM-7. Therefore, careful attention should be paid to that protein polymorphism, and deeper research is needed to verify the range and nature of its interactions with the human gastrointestinal tract and whole organism.