Woodford, KB2008-05-162008-040168-8227350OQ (isidoc)https://hdl.handle.net/10182/484The role of milk and milk proteins in relation to human health remains controversial. However, there is a large body of evidence, reviewed in this paper, specifically linking A1 beta-casein to a range of illnesses. A1 beta–casein is produced only by cattle of European origin. The proportion of European cattle producing A1 beta-casein varies by breed and country. High levels are found in many parts of northern Europe and also other parts of the world where particular breeds of European origin predominate. Cattle that produce A2 and not A1 beta-casein are known as A2 cattle. A2 beta-casein was the original variant. A1 beta-casein releases bovine beta-casomorphin7 (BCM7) on digestion. The amount and stability of BCM7 that is cleaved from A1 beta-casein is linked to the presence and levels of various enzymes, in particular dipeptidyl peptidase 4. BCM7 is a strong opioid. There are seven strands to the evidence linking A1 beta-casein and BCM7 to Type 1 diabetes. These include particularly strong correlations amongst developed countries between A1 beta-casein intake and Type 1 diabetes incidence (r²=0.84, p<0.00001). Supporting evidence comes from biochemistry (structure of A1 beta-casein and cleavage of BCM7), pharmacology (opioid characteristics and binding affinities of BCM7), animal trials (NOD mice and BB rats), immunology (people with Type 1 diabetes have enhanced levels of antibodies to beta-casein and in particular A1 beta-casein), and human studies (high milk intake in children linked to high incidence of diabetes). A plausible auto immune mechanism relates to the homology between an amino acid sequence in both BCM7 and the GLUT2 glucose transporting molecule produced within the pancreas. Countries with high levels of Type 1 diabetes are the same countries that have high levels of heart disease (r²=.74, p<0.001). This strongly suggests linked factors of causation. A1 beta casein intake also correlates strongly with heart disease (r² up to 0.86, p<0.001). Supporting evidence includes an animal trial with rabbits, and LDL oxidation by BCM7. BCM7 has also been linked to symptoms of autism and schizophrenia (animal and human trials) and BCM7 has been widely reported in urine of autistic people. Intestinal and stomach permeability appears to be a common feature of all conditions where A1 beta-casein has been implicated. This permeability occurs in all babies and can occur for a range of health reasons in children and adults. The debate about A1 and A2 beta-casein has largely been occurring in New Zealand and Australia. NZ has been typing all breeding bulls for A1/A2 status for approximately 10 years, and the national herd is drifting towards A2. However this is mainly because of a serendipitous association between A2 cattle and particular characteristics that are sought within the NZ breeding system (high protein production efficiency rather than milk production per cow). The national herd could convert to A2 over about a 10 year period. No other countries are routinely typing their bulls for A1/A2 status. Although the scientific and medical evidence is published in peer reviewed journals it has not been widely reviewed as an integrated body of evidence. This paucity is linked to the breadth of encompassed disciplines. Further, much of the early research was undertaken from within the mainstream dairy industry, particularly in NZ. This industry has subsequently chosen to regard the A1 versus A2 issue as a threat rather than an opportunity, and has mounted a sophisticated public relations and political campaign that A1 versus A2 is a non issue.pp.S3-S3enA1 beta-caseinA2 beta-caseinhealthdiseasediabetesmilkConference Contribution - publishedMarsden::321200 Public Health and Health Services10.1016/S0168-8227(08)70650-8ANZSRC::3202 Clinical sciencesANZSRC::4206 Public healthANZSRC::5203 Clinical and health psychology