A2 milk is cow’s milk that contains only the beta-casein protein called A2. This is the only difference from traditional cow’s milk, which contains both A1 and A2 beta-casein proteins and can be difficult to digest. When A1 beta-casein is broken down in the gastrointestinal tract, it produces a peptide that can cause inflammatory reactions in the intestines, similar to the symptoms of lactose intolerance.
The drink was first introduced by a New Zealand company called The A2 Milk Company. Since 2000, the founders of the company have been interested in working with cattle that carry only the A2A2 gene (the only cows that can produce A2 milk). Today, farmers around the world breed their own cattle with the A2A2 gene and sell their milk as a product that is preferable for the intestines.
Even though the protein composition of A2 milk is different from regular cow’s milk, it still contains lactose. Companies and brands that sell A2 milk clearly state that their product is not suitable for people diagnosed with protein allergy or lactose intolerance. At the same time, the amount of total protein in such milk is no less than in traditional milk ~3.5 g per 100 ml.
Source: healthnews