Dairy: A1 vs A2 Milk

A1 vs A2 milk. What’s the difference? Americans consume 655 pounds on average of dairy per year. That is a lot of dairy. So what kind of milk should we be consuming?

One of the first things we need to do is to determine whether or not the dairy we are consuming is from A1 or A2 beta-casein cows.

Why is A1 milk everywhere?

Beta-Casein makes up about 30% of the protein in cow’s milk but that 30% can make a huge difference in how cow’s milk affects a person. Historically, most cows contained only A2-beta casein in the milk.

However, in grocery stores today, 99% of cow dairy will be from cows that produce A1-beta casein milk. 

The reason most cow dairy is of the A1 variety now is because farmers found that the A1 genetic mutation found in cow breeds like Holstein, British Shorthorn, Ayrshire, Friesian produced a lot more milk at a significantly lower cost. Once again money won out, in spite of the potential health downside of A1 milk.

Conversely, milk that is high in A2 beta-casein can be found in breeds like Guernsey, Jersey, Charolais and Limousin. 

However, just because you have a jersey cow though doesn’t mean it will be 100% A2.

A1 vs A2 milk

A study published in 2016 in the Nutrition Journal demonstrated that A1-beta casein was associated with increased gastrointestinal inflammation, constipation, and decreased cognitive processing speed and accuracy compared to those receiving A2 beta casein milk.

A1 milk also down regulates glutathione expression which is the exact opposite of health accumulation. In my recent video on NAC (N-acetyl cysteine) I talked about its ability to raise glutathione levels and the benefits of supporting our master antioxidant glutathione.

In contrast to A1 cow dairy, 100% A2 cow dairy milk actually demonstrated an increase in glutathione concentrations by two fold.

The A2 protein structure is much more comparable to human breast milk, as well as the milk from goats, sheep, and buffalo. That in itself tells us it is likely to be less problematic given that goat, sheep, and buffalo milk are all considered low-allergy foods.

A1 Beta-Casein and BCM-7 peptide

Our understanding right now related to the problem with A1 beta-casein is related to the peptide BCM-7. Basically, BCM-7 is a metabolite created during the digestion of A1 beta-casein. 

BCM-7 seems to have an irritating effect on humans.

It has been linked to type 1 diabetes, heart disease, autism, and general digestive inflammation. 

The younger a child is introduced to A1 dairy and the greater their intake of A1 dairy is, the greater their risk for type 1 diabetes, this is the non-lifestyle induced type, where the immune system attacks the pancreas, decreasing and potentially eliminating its ability to produce insulin. 

There are a whole host of genetic and environmental factors associated with type 1 diabetes but given that causal relationship with A1 beta- casein, I think it is well worth reducing or eliminating A1 dairy on a regular basis.

BCM-7 and Glutathione

BCM-7, has also been reported to down regulate glutathione expression in human gut epithelial and neuronal cell lines by limiting cysteine uptake.  

Of course we have talked about the benefits of N-acetyl cysteine many times for its ability to raise glutathione levels.  So it is not to our benefit to consume something that will slow down our ability to create our master antioxidant glutathione.

Cow Dairy and Lactose Intolerance

I have found that many patients who could not consume cow dairy due to side effects and thought lactose was the problem, could consume goat milk and goat whey without issue. 

This suggests lactose was not the issue as lactose is found in goat milk as well, however goat milk is an A2 milk.  Perhaps it was the BCM-7 and not a lactose issue.  Just a thought. 

Some food experts suggest that A1 milk could be a causative agent for actually creating lactose intolerance via its inflammatory impact on the digestive tract.

I recommend the following:

  • Goat milk.
  • If you have your own cow you are milking for the family, go to great lengths to find a 100% A2 dairy cow.
  • Find a friend or Co-op that has a 100% A2 dairy cow and get your dairy products through them.

Have you experienced any difference between A1 and A2 milk? I’d love to hear about it in the comments below.

2 thoughts on “Dairy: A1 vs A2 Milk

  1. Angie

    I just came across your article when looking up BCM7 explanation for a family member. Great article! I had no idea about the glutathione connection. I had genetic testing done a couple years ago and the specialty Dr told me I had some sort of dysfunction in my glutathione pathways (not sure if I am explaining that correctly) and/or low glutathione levels based on extensive other types of tests run. I have a lot of genetic health issues, histamine difficulties, potential mast cell activation syndrome and cfs, but I feel so much more well if I take NAC, molecular hydrogen, and nebulize glutathione if I have a virus. It literally can be felt about 30 mins after. I wonder if this is one reason why A1 milk is a huge reject by my body bc it depletes me even further. Also A2 milk has amino acid proline that was replaced by the mutation in A1 by histadine, which converts to histamine in the body. Another blow to my system for A1!
    My whole family “can’t have milk”, though some seem more tolerant of it as they age or can use it occasionally. “The milk cold” when we were young….constant bouts of tonsillitis, same day draining throat after eating an item with dairy in it. My dad and I get terrible digestive upset now from it…..until I discovered I can have goat milk, and sheep milk, and buffalo milk, and was even tested as an adult for dairy allergy for 8 different cow milk types and no allergy….but cow butter on veggies at a banquet, one tbsp of cow milk even if organic, non homogenized, cream top, low temp pasteurized, small family farm (like Kalona brand), and even long fermented as kefir…terrible gas and stomach pains and then unhappy gurgling bowels for days, fluffy, looser stool. My dad and mom both went to Europe and neither had problems with the milk over there which happens to be predominantly a2. About two years ago I stumbled on someone saying goat, sheep, buffalo are all a2 dairy….and so I found that Alexandre Family Farm sold organic a2 milk thru nation wide co op Azure Standard. I tried it, so scared. NO REACTION. I tried cream. Such bliss!!!! No problems, not a twinge. It’s such a blessing!! We recently got our own family milk cow…yes she’s a2a2 (meaning her cow mother AND the bull father were both a2 genetics)…and we are just enjoying all the amazing quality and delights of fresh a2 milk! It doesn’t matter if pasteurized or not, the enzymes in the milk aren’t the difference (some suggest enzymes in raw milk may help digestion and I don’t dispute that, but in terms of my reaction it doesn’t seem to be affected by what enzymes are present or not). I am glad I can’t have A1 milk bc it forces us to make a healthier dairy choice.

    I saw no one commented so I couldn’t help but give you details of what I experienced.

  2. Lesley Mcsharry

    I had lifelong allergic rhinitis (sniffle-us) until I went onto soy. It is not an allergy but a sensitivity. One niece had the same problem and went onto soy. One day she was bought a milkshake from a friends Mum and woke up so conjested she was bleeding from the ear! Most studies i have seen are over a broad population and say A1 doesnt make a statistically significant difference to mucous production but they need to test the subset who fell th.ey have a problem on a double blind trial to see the condition is real The beta casein morpho 7 gets into the blood stream like the gliadin fragment in coeliac disease in certain individuals.. The one amino acid difference makes a weak bond. . I can tolerate A2 without a problem..


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