Some thousands of years ago a genetically different strain of milk appeared, now known as 'A1' milk. The original 'A2' milk is generally produced by cattle in Africa, Asia, France and Guernsey. Goat and camel milk is also 'A2'. Cattle in other countries generally produce mainly 'A1' milk. There is only one genetic difference between A1 and A2 milk, being the amino acid at position 67 in the chain of 209 amino acids that make up beta-casein protein in milk. In the case of A1 beta-casein the amino acid at position 67 is histidine, whereas with A2 beta-casein it is the amino acid proline... However this small difference results in the milk having quite a different chemical - and perhaps physiological - effect. This is because the proline forms a strong bond with the amino acids in positions 66 and 68. In A1 milk, the histidine linkage with its neighbours is more “easily broken by digestive enzymes... The breakdown of these links through digestion creates a protein fragment known as BCM7 (beta-casomorphin-7) which acts as an opiate."[2]




OPIATE