A2 milk is popular in the United States and has recently appeared on the Canadian market. It is marketed as being easier to digest. But what exactly is this product, and does it really provide additional benefits when compared to regular milk? Let’s shed some light on this question!
Cow’s milk contains lactose, which is a sugar, and two types of protein, whey and casein, the latter being 80% predominant in milks’ constitution. Cow’s milk contains several types of casein, including beta-casein. Finally, there are two variants of beta-casein, namely A1 and A2. In North America, most cows produce milk that contains an equal proportion of beta-casein A1 and A2. Elsewhere in the world, most cows produce milk that contains only beta-casein A2. The amounts of beta-casein A1 and A2 contained in milk are not associated with the cow’s diet, but rather with its genetic background. Beta-casein A1 is naturally found in the milk of cows carrying A1A1 or A1A2 genetic traits, while those with an A2A2 genotype produce milk containing only beta-casein A2. For example, the majority of Holstein cows have A1A1 or A1A2 genotypes, while the Jersey, Swiss Brown and Guernsey breeds have a higher frequency of the A2A2 genotype.
According to some theories, beta-casein A1 is more difficult to digest for some people because it may slow down the intestinal transit and could, therefore, lead to constipation. It may also cause inflammation and cause stomach upset and other digestive symptoms in people who are more sensitive. Although studies on the subject remain very limited at the moment, this may explain why some North Americans report better tolerating milk when traveling across the ocean.