What is A2, and why is it a good thing? Let's break it down: milk is a good source of protein. Of that protein, 30% is beta-casein, which has two variants: A1 and A2. The A1 protein has been linked to stomach discomfort and symptoms similar to lactose intolerance. The A2 protein, however, is more comparable to human breast milk (as well as goat, sheep, and buffalo milk), making it potentially easier to digest and more bioavailable. A2 milk is now available in stores even trad