The Differences Between A1 and A2 Milk

There are so many different types of milk and we've got 2 more for you! What are A1 and A2 milk?
The Differences Between A1 and A2 Milk
Diego Pereira

Reviewed and approved by el médico Diego Pereira.

Last update: 26 January, 2023

These days there’s a wide variety of different types of milk to choose from in the shops. We find skimmed, semi-skimmed, vegetable, lactose-free, soy milk, and many others. It’s often difficult to choose between them, especially when you want to prioritize their benefits and properties. Today we’ll show you the differences between A1 and A2 milk.

Since dairy components such as milk are essential in a balanced diet, you should know the differences between A1 and A2 milk. Knowing this can help you reduce the problems associated with its intake, such as inflammation and gastrointestinal disorders. We’ll show you how they differ and which one you should buy.

Main differences between A1 and A2 milk

The differences between A1 and A2 milk are microscopic
Types of A1 and A2 milk differ in the composition of some of the proteins they contain.

The first thing you need to know about the differences between A1 and A2 milk is that it depends on the protein present in the milk.

As experts point out, this depends on the genetic makeup of individual cows. That is, a specific type of cow produces milk with the A1 protein (A1 beta-casein) and another type with A2 protein (A2 beta-casein).

Proteins differ from each other in structure due to an amino acid substitution at position 67. The A1 beta-casein protein contains a histidine residue at this position (also its variants, such as B and C).

For its part, the A2 beta-casein protein contains a proline residue at this position (also its variants, such as A3 and D). The change in the amino acid in the A1 protein causes the peptide BCM-7 (beta-casein morphine) to be produced during its decomposition.

Studies and research have found that this peptide (generated after ingesting A1 milk) reduces the frequency and amplitude of intestinal contractions in rats. Similarly, it is known to increase intestinal mucus secretion and there’s evidence that it suppresses lymphocyte proliferation.

All these consequences have led many to believe that many cases of lactose intolerance are in fact a reaction to the breakdown of this peptide.

There’s also evidence linking excessive consumption of A1 milk with the development of cardiovascular disease. Similarly, some authors have associated it with a higher prevalence of type 1 diabetes.

Despite all this, researchers are still debating about the real harmful effects and benefits of choosing one type of protein or another in humans. The debate isn’t closed, and keep in mind that not everyone reacts in the same way to them.

What’s the best milk for you?

Differences between A1 and A2 milk are small.
The choice of the type of milk depends a lot on the taste of each person and how its consumption affects them.

The above may have seemed very technical to you, so what you really want to know is which is the best milk for you. We have already mentioned that there’s no consensus among specialists, so you have the last word! Some people respond better to drinking A1 milk, while others are comfortable with A2.

In general, if you have gastrointestinal difficulties when drinking milk, you can opt for type A2. During its decomposition, the typical sequelae such as bloating, stomach upset or diarrhea won’t appear. From a nutritional value point of view, there are no major differences between A1 and A2 milk, so you aren’t compromising your diet in the process.

The A1 protein is found in the milk of the Ayrshire, British Shorthorn, Holstein, and Fresian breeds of cows – those from northern Europe. For its part, the A2 protein is found in the milk of the Charolais, Guernsey, Jersey and Limousin cow breeds. In general, those that come from the south of France and the Channel Islands.

To conclude, remember that the presence of both proteins in milk is completely natural. The A2 protein has been here for millennia, and it wasn’t until a recent, fortuitous mutation that many cows manifested the A1 protein.

Also keep in mind that The A2 Milk Company has a monopoly on milk with A2 protein, and is in charge of promoting its product through studies and advertising. So now you know a little more to be able to make your mind up, but remember that there are also vegetable options available on the market.

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