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A2 milk takes the stores by storm

June 19, 2018

A new type of cow’s milk is appearing in supermarkets across the globe that may be easier for some people to digest than traditional cow's milk: “A2 milk.”

A new type of cow’s milk is appearing in supermarkets across the globe: “A2 milk.” Supporters of A2 milk, including consumers who report they cannot drink cow’s milk without suffering digestive issues, indicate that A2 milk may be easier to digest than traditional cow’s milk.

What is A2, and how can it affect me?

Cow’s milk is a good source of protein, containing 8 grams of protein per 8-ounce glass. The primary proteins in milk are casein and whey, with casein accounting for about 80 percent of the total protein. There are different types of casein, with one of the three major casein proteins being beta-casein. A1 and A2 are two variants of beta-casein.

Depending on a cow’s genetic makeup, it can produce A1 beta-casein only, A1 and A2 beta-casein, or A2 beta-casein only. Commonly, unless otherwise labeled, both A1 and A2 are expressed in the traditional cow’s milk found on supermarket shelves. There are small variations between the two proteins — they’re nearly identical — and while there is no strong scientific research on the topic, there is anecdotal evidence to suggest milk containing only A2 beta-casein is easier for some people to digest.

When A1 protein is digested in the small intestine, it produces beta-casomorphin-7 (BCM-7), a peptide that has been linked to stomach discomfort and symptoms similar to those experienced by people with lactose intolerance. 

Experiencing stomach discomfort (symptoms such as gas, bloating and diarrhea) after consuming dairy products is often attributed to lactose intolerance. However, a few researchers now believe that it may be BCM-7, not lactose, that is producing these symptoms in some people.1-3

A2 milk

The a2 Milk Company was founded in 2000 in New Zealand, providing milk from cows that only produce the A2 protein. The a2 Milk Company tests the DNA of its cows using a strand of hair from the tail of each cow to ensure the animals produce milk that contains the A2 protein only. These cows are then segregated and milked separately. The milk is also tested after production to ensure it does not contain A1 protein. The company owns the patent to the method for identifying the A2 milk cows, meaning it’s the only brand that can sell milk with the A2 label.4

Should I choose A2 milk over traditional cow’s milk?

For consumers who do not experience any digestive issues with milk consumption, there is no evidence to suggest benefits in drinking A2 milk over traditional cow’s milk, which contains both the A1 and A2 proteins.

But, for consumers who report digestive discomfort when drinking traditional cow’s milk, it may be a suitable option to be able to enjoy milk and its health benefits without symptoms.

It is important to note that A2 milk still contains lactose and milk protein, so it is not an appropriate alternative for people with diagnosed lactose intolerance, galactosemia or a milk allergy.



  1. Nutrition Journal. 2016 Apr;15(35). Effects of milk containing only A2 beta casein versus milk containing both A1 and A2 beta casein proteins on gastrointestinal physiology, symptoms of discomfort, and cognitive behavior of people with self-reported intolerance to traditional cows' milk.  Jianqin, S., Leiming, X., Lu, X., Yelland, G. W., Ni, J., & Clarke, A. J.
  2. Eur J Nutr. 2014 Jun;53(4):1039-49. Comparative evaluation of cow β-casein variants (A1/A2) consumption on Th2-mediated inflammatory response in mouse gut. Ul Haq MR1Kapila RSharma RSaliganti VKapila S.
  3. Int J Food Sci Nutr. 2014 Sep;65(6):720-7. Dietary A1 β-casein affects gastrointestinal transit time, dipeptidyl peptidase-4 activity, and inflammatory status relative to A2 β-casein in Wistar rats. Barnett MP1McNabb WCRoy NCWoodford KBClarke AJ.


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