What is A1 Versus A2 Milk?

Faith Schlabach

Faith Schlabach › Faith Schlabach and her husband, who grew up Amish, live on a farm between two mountains ...


On our dairy farm, the biggest concern is producing delicious, raw and unhomogenized milk. The second concern is to incorporate the best grazing genetics available and offer free choice grazing to our stock. The third concern is to work toward A2/A2 genetics and move away from A1/A1. What are A1 and A2 genetics you ask? A1 is a mutated beta-casein protein found in milk.

I first learned about the A1 genetic mutation in a 2009 Acres USA article and began a search for more information, which was very hard to come by. I finally discovered Keith Woodford’s book Devil in the Milk, which has become my main source of information. It was a bestseller in New Zealand where it was first published. The book sheds light on the possible link between the A1 genetic mutation and a range of serious health issues, including heart disease, type 1 diabetes, autism, and other aggravating neurological disorders.

It is believed that the mutated gene started in the Holstein cow breed hundreds of years ago, but has been passed to many other breeds because the Holstein cow has been used to “improve” the production of almost all breeds. Interestingly, the Guernsey breed only has 2-3% of their cows testing positive for the A1 mutation.

The health problems are believed to be caused by a tiny protein fragment formed when we digest A1 beta-casein, a mutated protein in the milk. Milk that does not contain this mutated protein is called A2 milk. Today, the majority of the cows in the USA carry the A1 gene. The beta-casein proteins found in cow’s milk are made of a string of 209 amino acids all linked together. The difference between A1 and A2 amazingly is just one of those amino acids. With A1 milk, number 67 is a histidine instead of a proline! The proline binds very tightly to the amino acids on either side of it where the histidine does not. The histidine breaks off forming a peptide of a string of 7 amino acids called beta-casomorphin-7. Casomorphins have opioid (narcotic) properties and are not digested well by some people. This apparently can possibly lead to health issues in certain individuals.

As I have researched this issue, there is still much that is not known. For example, does this mutation affect everyone or just certain people? Does it affect everyone a little bit and accumulate over the years or does it just accumulate for some? At this point, from what I have read, there are many strong links and clues, but more research has to be done to ascertain the full depth of the problem. This mutation was discovered a few decades ago but was kept under cover, so to speak, until only recently.

The A1 gene can be bred out of a herd in about 10-15 years simply by choosing what are called A2/A2 sires. This means that neither the dam or sire carry the A1 gene. Unfortunately, until the consumer is educated and begins to request A2 milk, the motive will not be there for the selective breeding in most dairies. Interestingly, New Zealand labels A2 milk in their grocery stores. There is some criticism of the A2 Corporation, a private New Zealand company, for controlling the volume on the A1/A2 genetic issue. They have even been accused of capitalizing on it. However, I have to agree with the prospective that there are very large dairy organizations and companies that would like to keep this information from the public so they do not have to go through the work of switching over their herds. In other words, it’s all about efficiency, profit, and momentum, not necessarily what is best for the people. At least the A2 Corporation is making a profit and raising the bar for conventional dairies on this issue (therefore accomplishing a little good).

In our family’s case, we can drink any milk without the adverse severe allergy reactions as long as it is raw (as I explained in an earlier article). We feel amazingly better and have halted cavities. I used to think I digested A1 milk as well as the A2 milk, but I have been rethinking this recently. In just the past couple of weeks we switched from milking our A1/A2 Blossom (who is my favorite cow) to our A2/A2 Emma Lou. I have noticed two things:


I find that very interesting. I’m going to keep taking notes and looking for changes, but I think I’m sold that there is some residual effect for me when I drink A1 milk. Certainly, any raw milk is MUCH better than processed milk, but I think not as good as it can get with A2 milk. My thought is since we don’t know the full scoop on the issue, let’s err on the side of safety. To my husband and me, it is clear that we need to be breeding this mutated gene out of our cows.

At this time, there are plenty of A2/A2 sires available especially in full-sized breeds; therefore, we see no reason not to breed only A2. If you breed an A1/A1 dam to an A2/A2 sire, you will throw an A1/A2 as they get one from each side. If you breed an A1/A2 dam to an A2/A2 sire, you have a 50% chance of throwing A2/A2.

What can you do? You can ask your source for local milk if they are breeding for A2/A2 milk. If they do not understand it, you can refer them to me or this article. Real Milk.com is one resource to find a local herd share program. Your local farmers market or CSA, which can be found at LocalHarvest.org would be another. Please do not contact them to ask if you can buy milk unless it is legal in your state. You can sometimes find farms that let you buy a share of the herd and pay the farmer to care for your cow. In exchange, you get to enjoy all the benefits of co-owning a cow such as milk (obviously) and manure for your garden. You could also consider purchasing your own milk goat (they do not carry the A1 gene), buy a cow with A2 genetics, or buy a cow with the plan to breed A2 genetics and select future heifers.

Have you heard about A1/A2 genetic mutation in milk before?

Photo Credit: Rothwell Photography