A2 milk is a type of cow’s milk that only contains the A2 type of beta-casein protein. Supporters of A2 milk claim that it is easier to digest and absorb than other types of milk.
This article provides an overview of A2 milk, its possible health benefits and risks, and current research surrounding the product.
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A2 milk is cow’s milk that contains only the A2 type of beta-casein protein, instead of the more common mix of A1 and A2 beta-casein found in regular milk.
In other words, A2 milk is just like regular cow’s milk in terms of nutrients, but it has a slightly different type of casein protein that may make it easier to digest for some people.
Historically, cows produced milk that contained only the A2 form of beta-casein. Today, most of the milk available from the local grocery store contains mostly A1 proteins.
A1 and A2 proteins affect the body differently.
When A1 protein is digested in the small intestine, it produces a peptide called beta-casomorphin-7 (BCM-7). The intestines absorb BCM-7, and it then passes into the blood. Doctors have linked BCM-7 to stomach discomfort and symptoms similar to those experienced by people with lactose intolerance.
The structure of A2 protein is more comparable to human breast milk, as well as milk from goats, sheep, and buffalo.
In 2000, a scientist in New Zealand founded the a2 Milk Company. This company provides milk from cows that only produce the A2 protein.
The a2 Milk Company test the DNA of their cows by using a hair sample, to ensure the animals only produce milk that contains A2 protein. The company test the milk after production, as well, to ensure it does not contain A1 protein.
Research in animals shows health benefits of A2 milk, but human studies are less clear. The strongest evidence so far is that A2 milk may cause fewer digestive problems than regular milk.
Symptoms of stomach discomfort, such as gas, bloating, and diarrhea that occur after consuming dairy products, are typically attributed to lactose intolerance. However, some researchers believe that it is BCM-7, not lactose, that affects digestion and produces symptoms similar to lactose intolerance, in some people.
A recent review emphasizes that A2 milk is easier to digest than conventional A1 milk, especially for individuals who experience lactose intolerance–like symptoms. This is attributed to a lower release of β-casomorphin-7 (BCM-7) during digestion, a peptide linked to inflammation and discomfort in sensitive people.
The review states that the popularity of A2 milk partly stems from reports connecting A1 casein, the protein variant in regular milk, to conditions such as type 1 diabetes, heart disease, and autism. However, these are primarily observational associations and do not establish a direct cause-and-effect relationship.
Recent studies have not highlighted any risks for consuming A2 milk. However, A2 milk still contains lactose and milk protein, so it is not appropriate for people with lactose intolerance, galactosemia, or a milk allergy.
Furthermore, some people choose not to consume dairy and to follow a vegan diet, the Paleo diet, or to try to reduce acne and other conditions by eliminating dairy.
There are many non-dairy milk alternatives available for purchase in health food stores or online. Each variety differs in its nutritional profile, protein content, and taste.
A note on A2 milk studies
It is important for people considering A2 milk to know that the a2 Milk Company and the dairy industry have funded most of the studies on A2 milk.
A2 milk is a type of cow’s milk that contains only the A2 variant of the beta-casein protein, unlike regular milk which usually contains both A1 and A2 proteins. The difference comes down to a single amino acid, but it changes how the milk is digested.
When A1 milk is broken down in the gut, it can release a peptide called beta-casomorphin-7 (BCM-7). This compound has been linked to digestive discomfort and, in some studies, to broader health concerns. A2 milk, by contrast, produces little or no BCM-7.