What is A2 Milk?
If you’ve been in stores recently, you’ve probably seen products that promote A2 milk. You’ve likely wondered, “what is A2 milk?”. Learn more about A2 milk, A2 milk benefits, and what sets it apart from other milk.
A2 Refers to a Form of Casein Found in Milk
In order to understand A2 milk, it’s helpful to know a little bit about the protein composition of milk. There are two main groups of proteins in milk; casein and whey. Casein is made up of a number of isoforms which include: alphas1-casein, beta-casein, alphas2-casein and kappa-casein.
The beta-casein isoform can be further broken down into two groups, based on a genetic variant; A1 beta casein and A2 beta casein.[1]
A2 Milk in Cow Milk
Historically, it’s believed that cows only produced A2 beta casein milk commonly known as A2 milk. However, a genetic mutation that research suggests occurred about 8,000 years ago, resulted in cows producing two types of beta caseins in their milk; the unmutated A2 beta variant and the mutated A1 beta variant also known as A1 milk. Subsequently, the A1 mutation spread widely throughout herds in the western world and now, the majority of cow milk currently available in the United States is A1 beta casein dominant.
A1 Milk May Contribute to Tummy Troubles
A number of recently published studies have shown that A1 milk, commonly found in cow’s milk, can cause health issues such as constipation, discomfort, loose stool and bowel inflammation in some individuals and perhaps even in some babies.[2,3,4]
A1 milk may contribute to these common tummy troubles because as A1 milk is broken down in the digestive system, it releases a short beta casomorphin peptide known as BCM-7.[5] BCM-7 has been shown to interact with opiate receptors in the gut to slow gastrointestinal transit.[6] Longer transit times may allow for increased fermentation of short-chain carbohydrates in the gut, causing gas, bloating and discomfort.
A2 Milk Benefits
In comparison, research shows that consuming A2 milk does not cause the release of BCM-7 and subsequently, has not been associated with symptoms of abdominal pain, stool frequency changes or constipation.[7,8]
A2 Milk in Goat Milk
Goat milk is predominantly A2 beta casein dominant. Goat milk, naturally contains little to no A1 beta casein.[9,10]For families who wish to enjoy dairy, choosing a milk that is gentle and easy to digest is really important. Kabrita Goat Milk Toddler Formula is based on goat milk and is gentle on tiny tummies.
Kabrita Goat Milk Toddler Formula may be an option for little ones during feeding transitions, such as weaning and supplementing, or those with minor issues associated with cow milk sensitivity*.
*Not suitable for children with confirmed cow milk protein allergy
[1] Pensabene, L., Salvatore, S., D'Auria, E., Parisi, F., Concolino, D., Borrelli, O., Thapar, N., Staiano, A., Vandenplas, Y., & Saps, M. (2018). Cow's Milk Protein Allergy in Infancy: A Risk Factor for Functional Gastrointestinal Disorders in Children?. Nutrients, 10(11), 1716. https://doi.org/10.3390/nu10111716
[2] Pensabene, L., Salvatore, S., D'Auria, E., Parisi, F., Concolino, D., Borrelli, O., Thapar, N., Staiano, A., Vandenplas, Y., & Saps, M. (2018). Cow's Milk Protein Allergy in Infancy: A Risk Factor for Functional Gastrointestinal Disorders in Children?. Nutrients, 10(11), 1716. https://doi.org/10.3390/nu10111716
[3] Kamiński, S., Cieslińska, A., & Kostyra, E. (2007). Polymorphism of bovine beta-casein and its potential effect on human health. Journal of applied genetics, 48(3), 189–198. https://doi.org/10.1007/BF03195213
[4] Defilippi, C., Gomez, E., Charlin, V., & Silva, C. (1995). Inhibition of small intestinal motility by casein: a role of beta casomorphins?. Nutrition (Burbank, Los Angeles County, Calif.), 11(6), 751–754.
[5] Defilippi, C., Gomez, E., Charlin, V., & Silva, C. (1995). Inhibition of small intestinal motility by casein: a role of beta casomorphins?. Nutrition (Burbank, Los Angeles County, Calif.), 11(6), 751–754.
[6] Brooke-Taylor, S., Dwyer, K., Woodford, K., & Kost, N. (2017). Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. Advances in nutrition (Bethesda, Md.), 8(5), 739–748. https://doi.org/10.3945/an.116.013953
[7] Kamiński, S., Cieslińska, A., & Kostyra, E. (2007). Polymorphism of bovine beta-casein and its potential effect on human health. Journal of applied genetics, 48(3), 189–198. https://doi.org/10.1007/BF03195213
[8] Brooke-Taylor, S., Dwyer, K., Woodford, K., & Kost, N. (2017). Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. Advances in nutrition (Bethesda, Md.), 8(5), 739–748. https://doi.org/10.3945/an.116.013953
[9] Jung, T. H., Hwang, H. J., Yun, S. S., Lee, W. J., Kim, J. W., Ahn, J. Y., Jeon, W. M., & Han, K. S. (2017). Hypoallergenic and Physicochemical Properties of the A2 β-Casein Fraction of Goat Milk. Korean journal for food science of animal resources, 37(6), 940–947. https://doi.org/10.5851/kosfa.2017.37.6.940
[10] Pattanayak S. (2013). Human health impact of bovine Beta-casomorphin-7 of milk — a question for milk products or our breeding policy ? Explor.Anim.Med.Res. 3(2): 93-94.