There’s a certain amount of a genetic variation in dairy cows, just the way there is with people. That’s why some of us are left-handed and some of us have red hair! And for Dairy cattle, one of those genetic variations leads to tiny differences in the proteins in their milk.
Beta-casein is the main protein in cow’s milk. And most of the dairy cattle here in the U.S. produce milk that contains two forms of beta casein…the A1 form and the A2 forms. But some cattle produce milk that contains only the A2 form of beta casein.
The milk looks and tastes exactly the same. It has the same nutritional profile—same amount of protein, calcium, same amount of lactose.
About 25% of the Western population experiences some degree of digestive discomfort after consuming cow’s milk…things like gas, bloating, or loose stools. We’re not talking about a milk allergy…that’s far less common and potentially more serious. These digestive symptoms are relatively harmless and temporary but they can be uncomfortable and inconvenient. And they are thought to be due to an inability to breakdown lactose, which is sugar in milk.
There are a few things you can do: You can avoid dairy products. You can take a lactase supplement when you eat dairy products, that’s an enzyme that helps break down the lactose so that it doesn’t cause problems. Or you can buy dairy products that have the lactose removed or reduced.
And there are now a handful of studies showing that for people with known lactose intolerance or who suspect they are lactose intolerant, drinking A2 milk, which only contains the A2 form of beta casein protein, may cause fewer digestive symptoms.
I think this is something that individuals will need to try for themselves to see whether or not it makes a difference for them. And if it doesn’t, there are other options for people who have trouble with dairy, such as the lactase supplements and lactose free milk.
It’s important to note that at this time there no other known benefits to consuming only the A2 protein and no other known risks of consuming the A1 form.