It is becoming increasingly difficult for food, agriculture and public health professionals to ignore the issue of A2 versus A1 milk. A1 milk has now been implicated in relation to Type I diabetes, heart disease, autism and schizophrenia.
The difference between A2 and A1 milk is only one amino acid out of 209 in the betacasein protein that is found in bovine milk. However, this one amino acid (histidene instead of proline at position 67) has major implications during digestion and leads to the formation of bovine beta-casomorphin7.
It is this peptide that appears to cause problems for a proportion of the population. Beta casein comes in two different forms, A1 and A2. The A2 gene determines whether the A1 or A2 protein is produced in a cow’s milk.Because an animal inherits one copy of the beta casein gene from each of its parents, its milk can contain just the A1 protein, just the A2 protein, or a mixture.
An A1A1 animal will always give the A1 gene to its progeny, an A2A2 animal will always give the A2 gene to its progeny, and an A1A2 animal can pass on either. Pure Indian breed of cow gives A2 milk that is why breed rectification must be given special importance.