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What Is A2 Milk?

author avatar Dr. Eric Berg 04/15/2024

Have you noticed an increasing number of milk products labeled as A2 milk in the dairy aisle? What is A2 milk, and should you consider incorporating it into your diet?

Discover why A2 milk may be an excellent option for individuals with lactose intolerance and learn why A1 milk consumption can cause stomach discomfort and may increase the risk of inflammatory health issues.   

Bottle of milk

What is A2 milk?

A2 milk contains high concentrations of A2 casein and little to no A1 casein. 

Cow’s milk consists of several proteins, including whey and casein. Beta-caseins are among the most predominant milk proteins, accounting for around 30 percent of the overall protein content of milk.  

A1 and A2 beta-caseins are the most common variants, and although they’re almost identical, they have a slight variation in their sequence of amino acids. 

The cow's genetic profile influences the beta-casein content of milk, with some cows producing A1 milk and others procuring A2 beta-casein-containing milk. 

Guernsey and Jersey cows have been found to produce milk containing predominantly A2 beta-casein proteins. In contrast, Holstein cows, the most common cattle species used in industrial dairy farming, produce milk with high concentrations of A1. 

Evidence shows that A2 milk consumption is associated with various health benefits and is less likely to cause gastrointestinal discomfort than traditional cow’s milk, which typically is high in A1 protein. 

Watch the video below to learn more about A2 milk. 

A1 vs. A2 milk

Although A1 and A2 casein are structurally very similar, their slightly different amino acid sequence can impact how the body responds to milk consumption. 

The digestion of A1 casein releases beta-casomorphin-7 (BCM-7), an inflammatory peptide associated with digestive discomfort, including abdominal pain, bloating, and diarrhea in sensitive individuals. 

In contrast, A2 casein breakdown doesn’t cause BCM-7 release, which may explain why A2 milk is generally better tolerated and associated with a lower risk of gastrointestinal problems. 

A study published in Nutrients found that individuals who are lactose intolerant experienced significantly fewer intestinal issues when consuming milk containing only A2 casein compared to drinking ordinary cows' milk high in A1 casein. 

In addition, food science research published in the Journal of Nutritional Biochemistry found that BCM-7 may be linked to changes in cognitive behavior and brain function due to its ability to cross the blood-brain barrier and influence neurological processes.

However, the impact of A1 milk consumption varies among individuals and depends on a person’s genetic predisposition, gut health, and overall immune system functioning.  

A1 and A2 milk

Benefits of A2 milk products

Increasingly, more evidence suggests that A2 milk reduces the risk of milk-related digestive discomfort and is associated with various other health benefits.

Here are three reasons why A2 milk may be the better choice. 

1. Digestive health 

Compared to milk with high concentrations of A1, drinking A2 milk won’t cause elevated levels of BCM-7, a peptide linked to intestinal inflammation, poor gut health, and impaired nutrient absorption.

“A2 milk and dairy products offer an excellent alternative to regular cow’s milk that’s typically high in A1 beta-casein and linked to protein sensitivities and inflammation,” explains Dr. Berg. 

The pro-inflammatory peptides in A1 milk can impair the intestinal mucosa, and choosing A2 milk can help lower the risk of intestinal permeability, also known as leaky gut.

A leaky gut allows pathogens and other potentially harmful substances to enter the body, which can trigger immune responses and perpetuate chronic inflammation. 

2. Lower risk of inflammation 

Evidence published in Advances in Nutrition compared the inflammatory effects of A1 with A2 milk and concluded, “A1 but not A2 consumption is associated with digestive discomfort and correlates with inflammatory markers in humans.”

Although there is limited evidence that A1 milk is directly linked to health risks, it may contribute to the body’s overall inflammatory load, potentially exacerbating inflammatory health issues such as heart disease, rheumatoid arthritis, or psoriasis. 

3. Skeletal health 

While there are many non-dairy calcium-rich foods, milk remains a significant calcium source for a large proportion of the population.

A2 milk is less likely to cause intestinal inflammation and malabsorption, and drinking A2 milk can promote the absorption of bone-building nutrients, including calcium and phosphorus.   

Woman holding a glass of milk

Who should choose A2 over A1?

A2 milk appears to be better digested, is linked to a lower risk of dairy-related gastrointestinal issues, and doesn’t raise pro-inflammatory peptide concentrations. 

A study published in The American Journal of Clinical Nutrition found that individuals with lactose intolerance or dairy sensitivities experienced significantly fewer digestive symptoms when consuming milk containing only A2 caseins.

In addition, people with chronic inflammatory conditions and infants and children with sensitive digestive tracts may benefit from choosing A2 over A1 milk. 

While avoiding A1 milk may help improve gastrointestinal symptoms, it’s crucial to consult a healthcare provider for a thorough evaluation of your health status if you experience persistent digestive problems. 

Ketogenic foods

A2 milk products on keto

There remains confusion surrounding dairy products and keto, and it’s often believed that whole cow's milk is keto-friendly due to its high-fat content.

However, all types of cow milk, including A2 milk, are high in lactose, a milk sugar that can quickly kick you out of ketosis. 

To keep blood sugar levels stable and maintain fat-burning, it’s best to avoid regular milk on a low-carb diet. 

However, low-carb A2 dairy products, including heavy cream, butter, and certain cheeses such as brie, blue cheese, and cream cheese, are on the keto food list and are excellent options for keto dieters sensitive to regular dairy products.   

Glass of milk

Key takeaways

What is A2 milk, and should you incorporate it into your diet? 

A2 milk contains little to no A1 beta-casein, which has been linked to dairy-related gastrointestinal issues, can trigger inflammation within the digestive tract, and may contribute to chronic inflammation. 

Choosing A2 milk products may be especially beneficial for individuals with lactose intolerance or dairy sensitivities, infants and children with sensitive digestive tracts, and those with inflammatory health conditions.   


1. What’s so special about A2 milk?

A2 milk contains only A2 beta-casein protein and little to no A1 beta-casein, which may benefit individuals sensitive to dairy products. 

Digesting A1 beta-casein causes the release of pro-inflammatory peptides, which can trigger intestinal inflammation, diarrhea, and abdominal discomfort in sensitive individuals.

2. What is the difference between A2 milk and A1 milk?

A1 milk contains A1 beta-casein, a protein linked to gastrointestinal issues and inflammation. In contrast, A2 milk contains only A2 beta-casein, which isn’t associated with adverse health effects. 

3. Is A2 milk genetically modified?

No, A2 milk isn’t genetically modified. The beta-casein content of milk is determined by the genetic makeup of the cow producing the milk. 

A2 milk is derived from cows that naturally produce milk containing A2 beta-casein, such as Guernsey and Jersey cows. In contrast, A1 milk comes from A1 beta-casein-producing cow species, such as Holstein cows, which are the most common cows used in the dairy industry.

4. Does A2 milk taste like regular milk?

While A2 milk generally has the same taste and texture as regular milk, it may have a slightly different flavor profile as it’s produced by different cow species, which can affect the taste.  

5. Can you have A2 milk on keto?

All cow’s milk, including A2 milk, contains lactase, a milk sugar that can impact blood sugar levels and explains why milk is generally not suitable for keto. 

However, certain low-carb dairy products made from A2 milk, such as butter, cream cheese, and heavy cream, are low in carbs and keto-friendly.  



  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9963893/ 

  2. https://pubmed.ncbi.nlm.nih.gov/27611101/

  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593102/

  4. https://pubmed.ncbi.nlm.nih.gov/31773165/ 

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