What is A2 Milk?

Updated: May 7

You’ve likely heard the term A2 milk by now. If you’re a regular consumer of Jersey Girl Organics then you know that we produce incredible organic, Jersey A2 milk.

But just what is A2 milk. How does it differ from A1 milk, and does it really matter? Let’s explore this in more detail.

What is A2 Milk?

Around 3-4% of milk is made up of protein, and approximately 80% of that protein is made of casein, a slow-digesting dairy protein that is common as a health supplement. It’s especially popular in the health space as a nighttime protein shake as it’s slow releasing nature can help you feel fuller, for longer.

Of this casein, there are a number of different forms, but the two most common are:

  • A1 beta-casein

  • A2 beta-casein

At a molecular level, these two forms are almost identical. The main difference between the two forms comes down to a single amino acid - yet this difference leads to big changes.

A1 beta-casein, it has a histidine amino acid, and A2 beta-casein has a proline amino acid.

For most of us, this means nothing. But what this change in amino acids does is affect how the two proteins are broken down, and what happens to our bodies as we break it down.

Most milk you find in the supermarket contains both the A1 and A2 proteins. A2 milk exclusively contains the A2 protein and comes from breeds of cows that have been bred to produce this type of milk, such as our beloved Jersey herd.

So, when you hear the term A2 milk, now you know that it refers to the type of the proteins found in the milk.

What's the Difference Between Regular and A2 Milk?

In reality, the only difference between A1 and A2 is how our bodies break down the amino acids histidine and proline differently, and how this can have negative effects on our stomach and digestive system.

When we break down A1 protein, the histidine amino acid, our bodies create a peptide called BCM-7 as a result. This peptide has been shown to affect gut movements and inflammation in animals, but so far no study has conclusively found these results to be replicated in humans.

What’s the Benefit of Drinking A2 Milk?

The benefit, therefore, is that A2 milk can be easier to digest, particularly for people with existing digestive issues or mild lactose intolerance.

There are also a number of other reasons why you should consider switching over to A2 milk:


A1 protein has also been linked with an increased risk of type 1 diabetes, although most studies looking into this link are observational and cannot prove that A1 causes diabetes, only that there may be a link between A1 consumption and a higher risk of developing the disease.

Heart Disease

Another observational study found a link between heart disease and A1 milk consumption in animals, but again the human effects have been debated within the scientific community.

A second study took a group of adults at high risk of developing heart disease and found that there were no major differences between A1 and A2 consumption and the impact on health markers such as blood pressure, blood vessel function or inflammation.

Lactose Intolerance

One of the most important differences between A1 and A2 milk is the impact on gut and digestive health and how those with slight lactose intolerance can drink A2 milk and feel much better compared to A1 consumption.

Multiple studies have confirmed that there is growing evidence to suggest A1 beta-casein leads to digestive problems and discomfort in some people.

A randomized, double-blind, crossover study in China found that “replacing conventional milk with milk containing only A2 β-casein reduced gastrointestinal symptoms associated with milk intolerance in Chinese preschool children, with corresponding improvements in aspects of cognitive performance.”

We’ve also had plenty of feedback from customers to support this evidence, and they claim that Jersey Girl Organics milk is the only one they can tolerate.

Can You Drink A2 Milk if You're Lactose Intolerant?

Short answer: it depends.

Depending on the severity of your intolerance, A2 milk may be suitable for you. A lot of the above information and research points to A2 milk being easier to digest, but this doesn't mean it is entirely safe for consumption if you have severe intolerance.

Your best bet is to pop down and see us on the weekend at one of our market stalls (find your nearest one here) and try a sample. Wander around and visit the other stalls and see how you feel. If everything seems to be fine, come back and take a bottle home. If everything goes well for the week, you'll know that A2 milk is fine for you to drink.

The Bottom Line

The differences between A1 and A2 milk are still debated. There is still research to be done to lead to conclusive results of both the negative and positive effects of both types.

Our recommendation? If you struggle with digesting milk, give A2 a shot and see if it clears things up (if you’re looking for your nearest stockist, check out our interactive map).

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