Tuesday, March 21st, 2023 20:46:21

The Better Milk: A1 or A2

Updated: May 5, 2017 2:08 pm

Cow milk is considered nature’s ideal food, providing a vital source of nutrients comprising carbohydrates, high quality proteins and selected micronutrients. More than 95% of the cow milk proteins include caseins and whey proteins. Among the caseins, beta casein is the second most abundant protein and has excellent nutritional balance of amino acids. Different mutations in bovine beta casein gene have led to 12 genetic variants and out of these A1 and A2 are the most common. At present, there are lot of talks about the health effects of A1 and A2 milk, which may depend on the breed of cow it came from. Currently, A2 milk is being marketed as a healthier choice than A1 milk. It is argued   to have several health benefits, and to be easier to digest for people who are lactose intolerant. Let’s have an objective look at the science behind A1 and A2 milk.

 Explaining A1 and A2

Casein is the largest group of proteins in milk, making up about 80% of the total protein content. There are several types of casein in milk, and beta-casein is the second most common. Beta-casein exists in at least 13 different forms. The two most common forms of beta-casein are:

  • A1 beta-casein:Milk from breeds of cows that originated in northern Europe and USA is generally high in A1 beta-casein. A1 milk comes from breeds like the Holstein, Friesian, Ayrshire and British Shorthorn.
  • A2 beta-casein:Milk that is high in A2 beta-casein is mainly found in breeds that originated in India and some other Asian countries. Studies indicate that A1 beta-casein may be harmful, and that A2 beta-casein is a safer choice. This is the reason for the “A1 vs A2” debate.

Conclusion: A1 and A2 milk contain different types of a protein called beta-casein. Studies indicate that A2 milk is  healthier of the two.


Beta-casomorphin-7 (BCM-7) is the reason why A1 milk is believed to be less healthy than A2 milk.

BCM-7 is an opioid peptide that is released during the digestion of A1 beta-casein .

Researches have suggested that BCM-7 is  harmful. BCM-7 may affect the digestive system.

Below is a review of the scientific evidence linking A1 milk and BCM-7 with type 1 diabetes, heart disease, infant death and digestive problems.

Conclusion: Western countries’ cow milk contains A1 beta-casein, which is partly broken down to beta-casomorphin-7 (BCM-7) in the stomach. BCM-7 has been linked with several adverse health effects.

Heart Disease

Two observational studies have linked the consumption of A1 milk with an increased risk of heart disease. This is supported by one experiment in rabbits. It showed that consuming A1 beta-casein promoted fat buildup in injured blood vessels. This buildup was much lower when the rabbits consumed A2 beta-casein.

Fat accumulation may potentially clog blood vessels and cause heart disease. Another study found no significant differences in the effects of A1 and A2 casein on blood cholesterol (17).

Conclusion: There is strong evidence that A1 milk increases the risk of heart disease.


Type 1 Diabetes

Type 1 diabetes is typically diagnosed in children, and is characterized by a lack of insulin in the body. Several studies indicate that drinking A1 milk during childhood may increase the risk of type 1 diabetes.

Conclusion: Several observational studies have found a link between A1 milk consumption during childhood and increased risk of type 1 diabetes. A2 milk causes no such problem.


Autism is a mental condition characterized by poor social interaction and repetitive behavior. In theory, peptides like BCM-7 might play a role in the development of autism. One study of infants found higher levels of BCM-7 in those who were fed on western countries’ cow’s milk, compared to those who were breastfed. However, levels of BCM-7 dropped quickly in some of the infants, when they were fed on A2 milk.

Another study indicated that drinking A1 cow’s milk may worsen behavioral symptoms in autistic children.

Conclusion: Some studies suggest A1 milk may cause autism.

Sudden Infant Death Syndrome

Sudden infant death syndrome (SIDS) is the most common cause of death in infants less than one year of age. SIDS is defined as the unexpected death of an infant, without an apparent cause. Some researchers have speculated that BCM-7 may be involved in some cases of SIDS.

One study found high levels of BCM-7 in the blood of infants who temporarily stopped breathing during sleep. This condition, known as sleep apnea, is linked to an increased risk of SIDS. These results indicate that some children may be sensitive to the A1 beta-casein found in Western countries’ cow’s milk.

Conclusion: Researches prove that A1 milk may increase the risk of sudden death in infants.

Digestive Health

Lactose intolerance is defined as the inability to fully digest the sugar (lactose) found in milk. This is a common cause of bloating, gas and diarrhea.

The amount of lactose found in A1 and A2 milk is the same. However, some studies suggest that A2 milk causes less bloating than A1 milk. Additionally, studies in rodents indicate that A1 beta-casein may significantly increase inflammation in the digestive system.

Conclusion: There is growing evidence that A1 beta-casein may affect digestive function, whereas A2 causes no such adverse effect.


 By Uday India Bureau

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