What is A2 milk?
A1 & A2 milk contain different types of a protein called beta-casein.
Regular milk contains both A1 & A2 beta-casein BUT A2 milk contains only A2 beta-casein.
A2 milk is cow’s milk that contains only the A2 variant of beta-casein protein. Research has found that A2 milk prevents some symptoms of dairy intolerance & eases others, even though it contains the same amount of lactose as regular milk.
All cow’s milk contains six proteins: two whey proteins & four casein proteins (the equivalent to about two teaspoons per litre of milk).
Caseins is the dominant protein family in cow’s milk. Caseins make up 80% of the milk protein. There are several types of casein in the milk including alpha, beta & kappa caseins.
All proteins are made up of long chains of amino acids & beta casein has a chain of 209. During digestion in the stomach or gut, enzymes break down the amino acids by interacting with them at specific locations on the protein chain. Position 67 in beta casein’s chain is in one such location & this is where the change occurs.
(Diagram courtesy of Details in Devil In The Milk by Keith Woodford)
The only difference between A1 & A2 beta-casein is the amino acid in position 67 where the weakness in A1 beta-casein splits seven proteins from the chain (BCM7)
The splitting of the beta-casein in A1 milk & not in A2 milk is the reason that A2 is believed to be the healthiest
The milk tastes no different. The cows look no different. BUT the milk may be healthier for you.